WO2011116647A1

WO2011116647A1 - Switching method, device, product and application thereof

Info

Publication number: WO2011116647A1
Application number: PCT/CN2011/071185
Authority: WO
Inventors: Holmer Jan; Kleen Dennis; Lowenborg Claes-Coran
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2010-03-23
Filing date: 2011-02-23
Publication date: 2011-09-29
Also published as: CN102598176B; CN102598176A

Abstract

A rotary contact switching device and product and method of switching the rotary switch are provided. The device comprises a stator part (501) comprising lead contact members (502,504,506), and a rotor part (508) comprising electrically conducting bridging contact members (509,510) having a first part and a second part. Wherein at least one electrically conducting shielding member (511) is arranged between the bridging contact members (509,510), and the shielding member (511) makes electrical contact with at least one stator ground contact member (503,505,507) of the stator part (501), when the rotor part is set in the stator part (501) in one of its angular switching positions. The contact switching device is a multi-pole contact switching device providing good isolation between poles, and providing radio frequency signal power transfer at a small loss.

Description

SWITCHING METHOD, DEVICE, PRODUCT AND APPLICATION THEREOF

Technical field

The technical field of radio frequency power crossover transfer provides relevant art of technology for this specification of an invention. This may also be the case for a technical field 5 of radio frequency switches and rotary switches.

Background

Radio frequency, RF, signals provide a means of transferring information signals across large distances. Briefly, the greater the radio frequency transmission power, the greater

communication distance may be bridged. When constructing apparatuses for transmitting radio0 frequency signals, they may be equipped for a particular maximum transmission power level to fit with e.g. an operator's deployment plans. To provide for wider bandwidths, carrier frequency tends to be increasing. When operating frequency increases, difficulties and challenges due to nature of RF signals increase.

To make apparatuses or deployment thereof more flexible, feeding of transmit power may be5 made selectable for feeding transmit power to one or more outputs, such as cable connections or feed cables. By combining transmit power from a plurality of power amplifiers, PAs, to a single output, a great maximum output transmit power may be achieved for a same transmit equipment capable of distributing the transmit power from the plurality of PAs to a plurality of outputs, each providing a smaller maximum output transmit power, where sufficient or desired. Such0 transmit power combining is, e.g., applicable to radio base stations in mobile communications systems, radio broadcasting or virtually any radio frequency signal feeding.

Switches are commonly used in electronics for establishing electrical connections. Figure 1 illustrates schematically block elements for some example switches. A first switch (1 10) illustrates a typical on-off switch. A first input (1 11) is connected to or disconnected from an5 output (112). In this specification, this is referred to as a Single Pole Single Throw, SPST, switch. There is a single switch contact (113) and a single conducting position. A second switch (120) illustrates a pair of SPST switches (110) with synchronized operations, indicated by a dotted line, so that either both switches are conducting (on), connecting input terminal ( 121) to output terminal (124) and input terminal (122) to output terminal (123), or both switches are off, with the output terminals (123, 124) remaining open as illustrated in the figure. Such a switch is referred to as DPST (Double Pole Single Throw) switch. A further switch arrangement (130) also illustrates a switch of two synchronized poles. In contrast to the DPST switch (120), this switch (130) has two contacting positions both of which are synchronized, as indicated by the dotted line, either the respective contacts connects input terminals (131, 132) to an upper output terminal-pair (134, 136) or a lower output terminal-pair (133, 135). Consequently, such a switch is referred to as double pole (two contact elements) double throw (two contacting positions), DPDT. Finally, a switch similar to the on-off or SPST switch (1 10), but with an additional output terminal for switching a single input (1 1) between output terminals (142, 143) is illustrated. In analogy, this switch (140) is referred to as an SPDT (Single Pole, Double Throw) switch.

US Patent Application US2009061846 describes a circuit switching circuit transferring RF transmit power of input RF circuits to output RF circuits, illustrated by the input RF circuits being radio base station apparatuses and the output RF circuits comprising measuring instruments. RF transfer switches on routes between input and output RF circuits are switched to connect each of N input RF circuits to each of N output RF circuits having a relay control circuit switching RF relay transfer switches in a predetermined time period.

Normally, relay switches are depending on a DC (Direct Current) current for closing or breaking, and also for staying in one of the two switching positions (connected, disconnected). A connection signal pulls one or more contact surfaces of a relay switch into engagement by means of one or more solenoids.

Semiconductor switches usually rely on two states, on-state and off-state, of a PIN diode comprising p-type doped, intrinsic and n-type doped regions. Briefly, a PIN diode is a current controlled semiconductor device that operates as a variable resistor at RF. US Patent US5109205 provides a millimeter wave microstrip shunt-mounted PIN diode switch having its DC ground separate from RF ground by utilizing a fan structure (radial stub). The radial stub provides RF ground at a radius of approximately one-quarter wavelength. A DC bias is coupled at that location, thereby reducing need of blocking capacitors. Two PIN diodes switch a single RF input port to either of two RF output ports according to SPDT. International Patent Application WO200903071 discloses a switch having at least two switch levels, each comprising a plurality of contact surfaces disposed on a contact carrier, of which at least two contact surfaces can be electrically connected to each other via a contact piece that is moved by a drive shaft. Each of the plurality of contact surfaces of one switch level contacts external lines via a spring force clamp, said lines being fed at an insulated end into a corresponding line guide, wherein the spring force clamps receiving the insulated line end are each electrically coupled to the corresponding contact surface via a contact tab.

US Patent US3940584 discloses a switch particularly adapted to be used as a coaxial cable switch for cable televisions systems because of its isolation of the signal inputs. The switch comprises an electrically insulating body, first, second and third terminals located on the body in spaced relation ship, a movably mounted contact, which is movable along a predetermined path to form alternative conductive paths between the first terminal and either of the second or third terminals, and a partition means between said terminals and located adjacent the path of the contact to form a barrier to radiated signals from whichever of the second and the third terminals that is not in contact with the movable contact. Additionally, terminating means for the unused terminal and/or shielding means to further isolate the unused terminal from the used terminal can be provided.

Dutch patent NL22967 discloses a rotary switch with spring contact pins parallel to the axis of the rotary switch. The spring contact pins are attached to a leaf spring that is movable around the axis of the rotary switch.

Japanese Patent Application JPl 1283455 provides a contact mechanism comprising a conducting resin placed inside a case whose outer contour part is made by an insulating member and the resin is shielded. The conducting resin is claimed to provide a leaking-free shielding as it is made integral with the casing, thereby reducing leakage and loss of high frequency signals. Another well known means of interconnecting various inputs to particular outputs is by transfer crossover cables.

Summary

Preferred embodiments of the invention have demonstrated nominal operating frequencies up to 3 GHz and average power transfer capacity of up to 1 0 W. At these transfer power levels also small losses may cause substantial heating of devices and equipment. Heating reduces equipment lifetime and may require additional cooling in addition to being inefficient.

To achieve high transmit power at high frequencies is demanding.

Cited prior art technology provides switches with which it is difficult or impossible to achieve satisfactory radio frequency power transfer capability at such high frequencies and power levels. Also, prior art switches are not sufficiently power efficient or satisfactory small.

Prior art of technology as cited does not disclose or suggest a switching contact suitable, e.g., for power transfer facilitating combining of transmit power from a plurality of power amplifiers in the relevant frequency range at relevant transfer power levels. Consequently, it is an object of an embodiment of the invention to transfer radio frequency signal power from a first port to a second port of a switch with a small loss.

A further object of example embodiments of the invention is to provide multi-pole switching reducing required PCB area when mounting.

An object of a preferred embodiment of the invention is to provide multi-pole switching capable of good isolation between poles.

Also, it is an object of an example embodiment of the invention to provide for switching that is capable of facilitating electronic monitoring of switching position.

Another object of an example embodiment of the invention is to provide power transfer switching suitable for surface mounting devices, SMDs. Also, an object of embodiments of the invention is to provide power transfer switching facilitating termination of an output port while not connected to any power amplifier.

Additionally, it is an object of an embodiment of the invention to provide for switching capable of switching when mounted under an EMC (Electromagnetic Compatibility) seal or climate safe cover without breaking or destroying the EMC seal or climate environment. Finally, it is an object of an embodiment of the invention to provide multi-pole switching capable of being remotely controlled. The invention provides method, use and equipment of radio irequency signal multi-pole contact switching and power transfer as described in detail below.

Brief description of the drawings

Figure 1 illustrates schematically block elements for some example switches, as known in the art.

Figure 2 illustrates an example circuit providing "low" transmit power levels to output terminals from input terminals according to principles of prior art technology.

Figure 3 illustrates an example circuit providing "high" transmit power level to output terminal from input terminal across a power combiner according to principles of prior art of technology.

Figure 4 illustrates a block diagram of a switching circuit, schematically an extension of DPDT, corresponding to an embodiment of the invention.

Figure 5 depicts an exploded view of a rotary contact switching device according to an embodiment of the invention. Figure 6 illustrates a slanted view of an example stator part inclusive of lead contact members and ground contact members in accordance with the invention.

Figure 7 illustrates a top view of an example stator part inclusive of lead contact members and ground contact members in accordance with the invention.

Figure 8 illustrates in detail an example contact rotor part in accordance with the invention from a first view angle.

Figure 9 illustrates in detail the example contact rotor part of figure 8 from a second view angle.

Figure 10 illustrates a cross-section view of an example assembled SMD (Surface Mount Device) contact switching device mounted on a PCB (Printed Circuit Board) under an example EMC (Electromagnetic Compatibility) cover according to an embodiment of the invention. Figure 11 illustrates schematically an example rotary contact switching device in accordance with the invention.

Figure 12 illustrates an example circuit having double pole contact switching devices in accordance with the invention for a first switching setting. Figure 13 illustrates an example circuit having double pole contact switching devices in accordance with the invention for a second switching setting.

Detailed description

In radio telecommunication applications, routing of RF signals usually employs relay type electromechanical switches or semiconductor-based RF switches, e.g. transistor-switches or diode-switches. Often relay switches are SPDT switches, connecting a single input terminal to either of two output terminals.

Figure 2 illustrates an example circuit providing "low" transmit power levels to output terminals (203, 204) from input terminals (201, 202). In this switching stage, an illustrated power combiner (208) is not engaged. Two of the ports of the power combiner are connected to the input terminals (201, 202) across SPDT switches (205, 206), one of the ports is connected to an output terminal (204) across an SPDT switch (207) and one of the ports is connected to ground over a terminating resistor (209), e.g. 50 Ω. One of the outputs (203) is switched on or off across the SPDT switch (206) connecting directly to the input terminal (202). The circuit may be switched to provide "high" power output from one of the output terminals (204) and no output from another output terminal (203) as illustrated after switching in figure 3. In figure 3, SPDT switches (305, 306, 307) corresponding to the switches (205, 206, 207) in figure 2 have been switched in position for transmit power from inputs (301, 302) to be combined in illustrated power combiner (308) and output from one of output terminals (304). One of the output terminals (303) has been disconnected by switching the associated SPDT switch (306). As in figure 2, one port of the power combiner (308) is connected to ground via a terminating resistor (309), e.g. 50 Ω. The switches (205-207, 305-307) of figures 2 and 3 are switched in a synchronized manner to achieve the desired result. Relay switches form one type of switches of prior art technology for switching as in figures 2 and 3. From figures 2 and 3, it may be observed that there are three SPDT switches involved. In case one of the switches is malfunctioning, the desired property of controlling transmit power may be lost. The great number of switches involved also infers that circuit board wiring becomes extensive. This is particularly a problem for large transmission power levels of radio frequency signals where losses of, and coupling between, long wires or strip lines may be significant. An advantage of relay switches is that they may be remotely controlled, when desired. However, the control of relay switches (whether remote or not) requires wiring for the close/break current and associated additional surface area of a printed circuit board, PCB, when mounted on such.

Unless bi-stable action relays are used, the electrical control signal adds to power consumption of the final product, also during steady-state operations when no switching occurs. Also, relay contacts are costly due to among other things relatively complicated manufacturing and critical design. Not always quality of relay switches correspond to their high price leading to extensive costs for replacement of malfunctioning switches, and also results in reduced reliability of overall product. The greater the number of switches involved to achieve the desired functionality, the greater is also the risk of at least one malfunctioning switch, and consequently the risk of a malfunctioning circuit according to figures 2 or 3.

As already mentioned, a particular problem associated with RF signals is losses. For power amplifier, PA, circuitry, a substantial part of losses is identified to originate from conductors in output circuits of the PA. Even if relay switches are known to have relatively small losses, good isolation between terminals and be applicable also for large transfer power levels, the control circuitry for the relays occupies a considerable area/volume of the resulting product and requires a control signal current that may, at least sometimes, be significant as regards power consumption. With increasing operating frequencies, to fulfill the RF requirements in microwave frequency range, the relay contact structure tend become expensive. The greater the transfer power levels, the greater is the PCB area required for the relay switches. The greater the PCB area required the greater are inevitably the lengths of adjoining PCB conductor lengths. Associated with the greater conductor lengths, the power losses become greater.

A particular advantage of relay switches is that when mounted within an electromagnetic shield or dust/waterproof seal, they may still be switched without breaking the seal. There may also be particular climate environment protection cover, e.g. protecting from direct sun or for cooling that would be time-consuming to dismount and remount only to set a switch circuit in a desired mode of operation, even if not changed frequently. Particularly, such dismounting and remounting may be associated with reduced performance unless the seal and environmental protection is carefully preserved. This advantage effectively holds also for diode and transistor switches, collectively referred to as semiconductor switches.

Also, semiconductor switches provide some difficulties. For semiconductor switches, it is very difficult to simultaneously achieve low loss, high isolation and high power transfer capability. In order to transfer greater power levels, required PCB area is large and also power consumption required for electrical control of semiconductor switches may be great. In high power RF applications, also reliability of semiconductor switches may be an issue causing both great costs and poor functionality of devices relying upon such switches.

Most useful prior art manually operated switches require dismounting of an electromagnetic cover in a climate safe environment free from e.g. rain and dust that would otherwise impact on equipment reliability or performance.

As noticed, the block diagrams in figures 2 or 3 rely upon switching according to SPDT, contributing to extensive wiring. It is identified for an embodiment of the invention that amount of PCB wiring/strip lines is substantially reduced by relying upon switching according to what may be understood as an extension of DPDT. A block diagram of a corresponding switching schematically comprises one DPDT (401-410) plus one DPST (41 1-420) schematically illustrated in figure 4. The DPDT part (401^110) connects respective input terminals (401, 402) to either of two intermediary output terminals (405, 406), (407, 408), included for reasons of understanding and full correspondence to DPDT (130) according to figure 1. The intermediary output terminals (405^108) are interconnected to output terminals (403, 404). Thereby the input - output relation between input and output ports (401, 402, 403, 404) of the first part of the switching circuit diagram corresponds to the corresponding part of the embodiment. The DPST part (411-420) of figure 4, effectively corresponds to figure 1 (120), since imaginary terminals (416, 417) are merely off-states. No additional interconnections are required to arrive at output terminals (413, 414) from imaginary output terminals (415, 418). In contrast to the SPDT (120) and DPDT (130) of figure 1 , the switch contacts (409, 410, 419, 420) of the extension of figure 4 are all synchronized in operations according to the embodiment.

Figure 5 depicts an exploded view of a rotary contact switching device according to an embodiment of the invention. In figure 5, a stator part (501) is provided with lead contact members (502, 504, 506) and one or more ground contact members (503, 505, 507). The ground level connected to depend on application but is normally at least RF ground. This does not exclude an operational mode where it is also DC (direct current) ground level in addition to RF ground level. For a typical application, the lead contact members (502, 504, 506) are connected to leads of RF signal level for RF power transfer, unless disconnected as described in further detail below. The rotary contact assembly of the embodiment comprises a contact rotor part (508) with attached contact bridging members (509, 510) and an intermediary shielding member ( 11). Preferably the stator part (501) comprises a ring shaped cross-section area (518). The resulting hole (519) of the preferred ring shaped cross-section area (518) provides room for the shielding member (511) to extend and contribute to further isolate electrically the lead contact member during operations as described according to a preferred mode in more detail below. A spring member (512) makes the contact rotor part (508) flexibly movable in relation to a top rotor part (513). The top rotor part preferably comprises a gasket (514) for sealing e.g. when mounted protected by a cover. Preferably, the seal protects both mechanically (e.g. water, dust) and electrically (RF sealing). In a preferred embodiment, the gasket is made of electrically conducting rubber in the shape of a ring with a circle profile, while not excluding a rectangular profile, or flange profile. The top rotor part is preferably provided with a recess (515) to facilitate rotation by e.g. a screwdriver or coin. Preferably, the recess is a slot recess, not excluding recesses for other drive heads; e.g. cross, hexagonal or torx recess; or a bolt head, in place of a recess. During operations, the recess (515) is preferably filled or covered to prevent it from being filled with dust. In a preferred embodiment, a slot recess is provided with a lever

(516) that fits into the slot and is movably fastened to the head of the top rotor part by a pin (517). An advantage of a slot recess, and associated lever, is that it will also clearly indicate mode of operation, associated with rotor angular position in relation to stator. The stator part (501) and contact rotor part (508) are preferably made of plastic being both mechanically rigid and heat resistant to stand surface mounting technology, SMT, soldering process. Plastic materials with small dielectric losses in the relevant frequency range are particularly suitable and are known in the art. All contacting members (502-507, 509-511) are preferably made of metal, e.g. brass or copper beryllium alloy. Contacting surfaces are advantageously hard gold plated. Surfaces intended for soldering preferably have other covering making soldering easier, e.g. covering by a composition based on tin. This is particularly preferred for SMDs. When making contact switching devices in accordance with the invention, radio frequency properties of the stator part and preferably integrated lead (502, 504, 506) contact members are preferably considered due to radio frequency impact on elements acting as microstrip line elements when integrated in the dielectric of the body. The microstrip line element character of the lead contact members determines preferred dimensioning of the particular members, dimensioning of microstrip line elements being known as such in the art. The microstrip line element property of the contact members (502-507) is associated with they preferably being integrated in the molding of the stator part (501) according to specifications and the dielectric properties of the stator part (501). In the preferred embodiment, also impact of PCB ground plane on the microstrip line elements dimensioning is considered. The ground contact members (503, 505, 507) are arranged to engage with the shielding member (51 1) in the interior of the stator part (501). Such engagement may be achieved along (the interior of) either boundary surface of the stator part such as the cylindrical wall or the (partial) cylinder end boundary.

The contact rotor part (508) inclusive of shielding member (511) and contact bridging members (509, 510) is fit into the stator part (501). When assembled, the top rotor part (513) engages the contact rotor part (508) under pressure from the spring member (512) and snap-lock hook members (520, 521). The snap-locking may of course be replaced by other similar fastening without departing from the invention, though snap-locking is preferred for the embodiment as illustrated in figure 5 due to ease and speed of assembling in manufacturing of contacts. When the various parts (501, 509, 510, 511, 508, 512, 513, 514, 516, 517) have been snapped together to form one contact switching unit, the spring member (512) will provide an initial force that distributes via the contact rotor part (508) to the contact points, forming parts, of the bridging contact members (509, 510) and the stator part (501). Preferably, the pressure provided by the spring member ( 12) provides a pressure not greater than the top rotor may move in axial direction while stopped by the snap-lock hook members (520, 521) and the ring-shaped cross- section area (518).

Respective figures 6 and 7 illustrate a slanted view and a top view of the example stator part (601, 701) and lead contact members (602, 604, 606, 702, 704, 706, 708), ground contact members (603, 605, 607, 703, 705, 707, 709) and ring-shaped cross-section area (618, 718) and associated hole (619, 719) of figure 5 (501-507, 518, 519) and more clearly illustrate the microstrip line elements forming interior stator lead contact members (612; 712-715) and interior stator ground contact members (610, 611), preferably appearing in diametrically opposed pairs (712, 714) (713, 715), engaging with (part of) the shielding member (511) in the interior of the stator part (501, 601, 701) of the embodiment. The ring-shaped cross-section area ( 18, 618, 718) preferably comprises bulges/convexities or particular protrusions (622, 623, 722-725) on the side facing the contact rotor part (508). When mounted on a PCB, the ground contact members (503, 505, 507, 603, 605, 607, 703, 705, 707, 709) connected to a ground plane of the PCB, will provide the ground level between the bridging contact members of the rotary contact and substantially contribute to isolation between poles. As observable from an example contact switching device assembled in accordance with figure 5, the extension of the shielding member ( 11) in direction along an imaginary plane, comprising the diagonal of the cylinder, in the center of the cylindrical shape of the stator part (501, 601, 701) will effectively separate electrically all lead contact members of different poles of the rotary switch, thereby contributing to good or excellent isolation properties during operations. For reference, please also see figure 10 below.

Comparing the ring-shaped cross-section area (518, 618, 718) and associated hole (519, 619, 719) of figures 5, 6 and 7, figures 6 and 7 also more clearly illustrate the space provided by the hole (519, 619, 719) for shielding member (511) to extend into the three-dimensional extension of the cross-section area, thereby improving isolation between pair-wise microstrip line elements (712, 714), (713, 715) during operations.

When mounting contacts according to the invention on a PCB, the ground contact members (503, 505, 507, 603, 605, 607, 703, 705, 707, 709) preferably connect RF-wise to a surface copper ground plane on the PCB. The RF-wise surface copper ground plane may connect to such a DC- wise ground level through low impedance capacitors. Thereby a DC current may pass to/from one ground contact member (503, 603, 703, 705) from/to a (diametrically opposed) counterpart (507, 607, 707, 709) through the shielding member (511) when positioned to engage or make contact with ground contact members (503, 507, 603, 607, 703, 705, 707, 709). In a preferred mode, this property is made use of to provide an electrical position indicator. Such position indication and monitoring of position of switches may be crucial to, e.g., avoid damages of electronic equipment when operations require synchronized operations of switches that are not otherwise, e.g. by particular mechanical mechanism, synchronized. Mechanical synchronization of switching of poles within each contact switching device as such relaxes the requirements of such signaling. Also, particular setting of switches may be required for various settings of a radio frequency transmitter. Having such an electrical indicator, current switch setting(s) may also be monitored remotely, without ocular inspection on site of the switch setting(s). Due to the fact that essentially same ground contact and shielding members are used for the electrical indicator, requirements on additional PCB area for such electrical position indication is kept at a minimum, which is important in order to maintain RF performance. Consequently, even if (diametrically opposed) ground contact members in pairs are not necessary to provide a ground level of the shielding member (51 1) such an arrangement solves various identified problems of operations.

Figures 8 and 9 illustrate in more detail an example contact rotor part (508) in accordance with the invention from two different view angles as if the contact rotor were made of transparent or semi-transparent material (for the purpose of illustration), or with reference to a fixed view -point, a rotor revolved 90 degrees between figures 8 and 9. The example rotor comprises a slot recess (801 , 901) for retaining the shielding member (51 1). The shielding member (511) is preferably held firmly in the contact rotor part (508) by press fit into the slot recess (801, 901) of the contact rotor part (508). The contact rotor also comprises two recesses (802, 803, 902) for retaining the contact bridging members (509, 510). In each recess for retaining the contact bridging members, there is preferably a ridge (804, 805, 904) at the bottom. In similarity with a balance, the ridge (804, 805, 904) will make the ends of the contact bridging members (509, 510) flexibly adjustable in axial direction (see figure 5) orthogonal to the elongation of the recess/bridging members (509, 510). Thereby, contact pressure of the contact points of a contact bridging member (509, 510) is evenly distributed over the contact pair of each bridging member (509, 510). Close to the perimeter of the contact rotor, there are preferably recesses or indents (806, 807, 808, 809, 906, 907, 908, 909) distributed evenly along an imaginary circle on a same radius from the center of the contact rotor in proximity to a corresponding microstrip line element/stator lead contact member (612; 712-715). They correspond in position to bulges/convexities or particular protrusions (622, 623, 722-725) in the interior of the ring-shaped cross-section area (518, 618, 718) of the stator (501). The bulges/convexities/protrusions provide the function of lifting the rotor and, particularly, the bridging contact members (509, 510), during switching revolution of the contact rotor, and maintain the lifting action until the contact rotor has been revolved another 90 degrees (for a stator with four microstrip line elements) when the circularly next bulges/convexities/protrusions will fit into the indents and the contact rotor, and particularly the bridging contact members (509, 510), will make contact with microstrip line elements/stator lead contact members (612; 712-715) in the ring-shaped cross-section area (518, 618, 718). The lifting action upon revolving relaxes contact pressure during the switching and reduces wearing of contact surfaces of bridging contact members (509, 510) and microstrip line elements/stator lead contact members (612; 712-715) or other corresponding static contact members of the stator. Also, during the switching, mechanical forces on other parts of the contact switch will be reduced due to mechanical contact area being reduced to the tip areas of the bulges/convexities rather than the full of the ring shaped cross section area and make the switching operation easier for the operator, provided the plastic material of the rotor being sufficiently hard. The matching indents (806, 807, 808, 809, 906, 907, 908, 909) and bulges/convexities/protrusions (622. 623, 722-725) will also maintain switching position during operations due to the pressure from the spring member ( 12), thereby contributing to reliable contacting and power transfer.

Figure 10 illustrates a cross-section view of an example assembled SMD (Surface Mount Device) contact switching device (1001) mounted on a PCB (1002) under an example EMC

(Electromagnetic Compatibility) cover (1003) comprising a penetrating hole providing manual switching access of the contact switching device (1001) according to an embodiment of the invention. The figure illustrates an example sealing with a sealing surface provided in a plane parallel to both PCB (1002) and EMC cover (1003). However the exact sealing arrangement may be formed according to various alternatives depending on mounting tolerances and size requirements as should be known in the art as such without departing from the scope of the invention. For the example in the figure, a seal ring (1004) preferably provides dust, water and electromagnetic sealing between the example EMC cover (1003) and the contact switching device (1001). The seal preferably rests in a recession of the top rotor part (513). The resting of the contact switching device towards the EMC cover provides high vibration resistance of the contact switch assembly, and also to the mounting on the board, also without other means for fixing the switch to the board than soldering. To provide electromagnetic shielding, the top rotor part is preferably made of, or is plated with, electrically conductive material and the seal made electrically conducting. In the figure, it is also illustrated how a lever (516, 1013) optionally extends into a recession of the cover surface when the switch is positioned in one of its operating positions and the lever is put down into the slot recess (515) of the top rotor part (513, 1005), thereby contributing to maintaining a set angular switching position of the various rotor parts or members (1005, 1006, 1007) of the contact switch. As may be noted from the example embodiment of figure 10, a same spring member (1008) provides a force not only to the bridging contact members, but also to the sealing gasket (1004). Of course, this does not exclude other embodiments using different members for providing contact pressure and sealing pressure, or a single spring member providing contact pressure without providing sealing pressure. When mounted, the axial load on the snap-lock hooks (1009, 1010) is relieved by a small pressure provided by the EMC cover in an example embodiment as illustrated, and the pressure on bridging contact members and sealing ring is effectively controlled by the distance between PCB (1002) and EMC cover (1003), and the flexibility of the sealing ring (1004) and spring member (1008). The snap-lock hooks are preferably provided sufficiently long to allow some variation in tolerances as regards the distance between PCB and EMC cover. To provide for this flexibility, the width of a recess (515, 1011) in the cylindrical surface of the top rotor part (513, 1005) with which the snap-lock hooks engage is made sufficiently wide to allow for such axial translation. The figure also illustrates the proximity of a shielding member (1007) to a ground plane (1012), contributing to isolation between poles. Due to the electromagnetic nature of RF signals, distances or size of electromagnetic "holes" where RF signals may dissipate/propagate impact on electromagnetic performance, such as RF isolation. The shielding member (511, 1007) is preferably arranged in an embodied contact switching device as assembled to provide a small distance, e.g. 0.1 mm, between the shielding member (511, 1007) and a base reference plane (1012) of the contact. Thereby, when mounted on a PCB, good or excellent isolation between lead contact members (502, 504, 506) and contact bridging members (509, 510), effectively separating microstrip line elements (712, 714), (713, 715)/lead contact members (702, 706), (704, 708) of different poles electrically while the shielding member (51 1 , 1007) also being mechanically/physically separated from the PCB (1002) and a base reference plane (1012).

As an alternative, or complement, to exercise the rotary switch by ingress of the top rotor part, the rotary switch and associated mounting is preferably arranged for operations by accessing the shielding member ( 11, 1007) through the hole ( 19) in the cross-section boundary of the stator part (501) at the end of the contact switching device facing the PCB, when mounted. Of course, this requires a corresponding hole in a PCB on which it is mounted. By operating the shielding member, optionally by providing a light pressure while turning, operations from this end provides a relaxing pressure on the bridging contact elements and releases the contact rotor part (508) or its indents (806, 807, 808, 809, 906, 907, 908, 909) of the switch more easily form the /bulges/convexities/protrusions (622, 623, 722-725) in the stator part (501) and reduces mechanical stress when revolving/switching. For an embodiment of the invention having this feature in alternative, the top rotor part is preferably replaced by an inexpensive top of e.g. plastic being stable enough to provide the contact pressure during operations, while keeping the EMC cover completely closed on the side facing the top rotor part of the contact switch device for perfect sealing. A fixed dedicated gripping tool, matching the dimensions of the shielding member (511, 1007) is preferred for such exercising rotary operations through the stator part (501).

Figure 11 illustrates schematically an example rotary contact switching device similar to the embodied contact as depicted in figure 5. In contrast to the embodiment of figure 5, the embodiment of figure 11 comprises a cap (1101) without any drive recess replacing the top rotor part (513) of figure 5. Typically, the cap (1 101) provides a lid made of plastic, covering at least partially the rotor part of the contact. According to one example realization, the cap is perforated or has a penetrating hole (1102) as illustrated, thereby providing e.g. additional cooling of the interior of the contact as compared to a top rotor part without holes. In one preferred embodiment, it is also capable of allowing reuse of contact rotor part of other embodiments, optionally facilitating switching by the contact rotor part (1104) extending through the hole. Intermediary of the cap, providing a top rotor part replacement (1 101), and the contact rotor part (1104), a spring member (1 103) provides flexibility of the contact rotor part (1104) and provides contact pressure. Similar to figure 5, a shielding member (1105) separates the poles where each pole comprises a bridging contact member (1106, 1107). An exterior border frame (1108) of the cap/top rotor part (1101) provides a means of connecting the cap/top rotor part (1101) to the contact rotor part (1104), by means of snap-lock hook members (1 109, 1110) provided on the stator part (1111), exercising a counter-force to the force provided by the spring member translating to a contact pressure when assembled. Also, drive means (1113) access of the shielding member (1105) through a hole corresponding to the hole (519, 619 and 719 ) of figures 5, 6 and 7 in the stator part (501, 601, 701, 1 1 11) is schematically illustrated in figure 11. There are preferably example realizations where the drive or rotor part is manually operated to provide small cost, while excellent performance, for base stations mounted conveniently for manual operations by an operator, and example realizations where the drive is electrically operated by a motor part (1112) facilitating remote switching control. While, e.g. semiconductor switches and many relay switches need be controlled electrically, making electrical wiring for the control mandatory, this is not the case for an electrical switch as embodied similar to the drawings in figure 11. By having separate wiring (1114, 11 1 ) for motor control, not involving wiring for the control on a PCB, radio performance could be maintained as if the contact switch were manually operated, also for electrically/remotely operated devices. Of course, this does not exclude the embodied invention alternatively having corresponding wiring on a PCB on which the contact switch is mounted. In addition to the PCB wire path lengths advantage, a motor controlled switch as compared to, e.g., many relays is that there is no requirement of control current during power transfer operations after the switching position/operating position of the contact has been set in case of motor control. For motor controlled revolving of the rotor part, the position indication by means of shielding member (511 , 1105), ground contact members (503, 505, 507, 603, 605, 607, 609) and/or interior stator ground contact members (610, 611) is preferably included with the control processing for indicating when desired position has been reach and when to stop revolving the rotor part during motor/remote switching. Such processing may be included with or added to the indication monitoring processing, mentioned above, in hardware by dedicated circuitry or software by adaptation of a program product of processing of a microprocessor for the motor/remote switching control in addition to the position indication monitoring.

Figures 12 and 13 illustrate an example circuit having double pole switch contacts (1205, 1206; 1305, 1306) in accordance with the invention for switch settings corresponding to two different modes of operation. Figure 12 illustrates what may be described as a low transmit power configuration while figure 12 would then correspond to a high transmit power configuration. The importance of good isolation between ports has been stressed above. Typical requirements of isolation between a first RF signal path from input (1201) to output (1204) and a second RF signal path from input (1202) to output (1203) in low transmission power configuration is 70 dB. For high transmit power configuration, typical requirements of isolation is 30 dB between a path from first input (1301) to first output (1304) and a path from second input (1302) to second output (1303). Example embodiments in accordance with the invention meet these high requirements and furthermore provide an insertion loss that is sufficiently small for demanding applications as regards reliability, power efficiency and power transfer capability.

An advantage of the example circuit in figures 12 and 13 as compared to, e.g., the circuit in figures 2 and 3 relying upon three single pole switches is a considerably relaxed requirement on size of PCB area. It also provides greater freedom of circuit layout on a PCB further facilitating shortening of microstrip path lengths on the board leading to/from switch input/output. The reduced microstrip path lengths contribute to reduction of insertion loss for the switch circuit configurations in accordance with figures 12 and 13 as compared to the one in figures 2 and 3. Both small loss in each switch and the way the switches (1205, 1206, 1305, 1306) are interconnected in the configurations of figures 12 and 13 contribute to both good isolation and power transfer capability of the switch arrangement. As noticed when comparing figures 2 and 12, or figures 3 and 13, the circuit in figures 12 and 13 provides an additional termination resistor (1210, 1310). The option of the additional termination resistor provided by the contact configuration thereby facilitates termination of a TX (transmission) duplex filter. The position of shielding member ( 11) is schematically indicated (1211, 1311) in the figures contributing to the isolation between bridging contact members (509, 510) also schematically indicated (1212, 1213, 1312, 1313), and described in detail above. The various ports (corresponding to lead contact members of figures 6 and 7) of the switches (1205, 1305) are connected to stator contact members (1214, 1314) schematically indicated in the figures and corresponding to microstrip line elements/stator lead contact members (612; 712-715) in figures 6 and 7.

In this description, certain acronyms and concepts widely adopted within the technical field have been applied in order to facilitate understanding. The invention is not limited to units or devices due to being provided particular names or labels. It applies to all methods and devices operating correspondingly. This also holds in relation to the various systems that the acronyms might be associated with.

While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of combining the various embodiments, or features thereof, as well as of further modifications. This specification is intended to cover any variations, uses, adaptations or implementations of the invention; not excluding software enabled units and devices, processing in different sequential order where non-critical, or mutually non-exclusive combinations of features or embodiments; within the scope of subsequent claims following, in general, the principles of the invention as would be obvious to a person skilled in the art to which the invention pertains.

Double pole switches or four port switches provide examples of radio frequency transfer switching. Features described in detail above as generally applicable in nature applies to all multi-pole switching devices, methods, uses or products within the scope of the invention as specified in subsequent claims.

Claims

1. A method of switching a rotary switch having a first and a second operating angular switching position, the method characterized by providing an angular force on a rotor part of the rotary switch, thereby exercising the rotor part in both axial and angular direction in relation to a stator part, whereby a respective first part of a first bridging contact member, a second part of the first bridging contact member, a first part of a second bridging contact member, and a second part of the second bridging contact member, with the shielding member in position between the first bridging contact member and the second bridging contact member, is disengaged from a first stator lead contact member of the first operating angular switching position; and rotating the rotor part in relation to the stator part, whereby the respective first part of the first bridging contact member, second part of the first bridging contact member, first part of the second bridging contact member, and second part of the second bridging member is engaged with a second stator lead contact member of the second operating angular switching position and wherein at least one of a first part of the shielding member and a second part of the shielding member is in electrical contact with a stator ground contact member in both first and second operating angular switching positions.

2. The method according to claim 1 , comprising connecting the first part of the shielding member to a first stator ground contact member in the first operating angular switching position; connecting the first part of the shielding member to a second ground stator contact member in the second operating angular switching position; and connecting the second part of the shielding member to a stator ground contact member in the first and second operating angular switching positions.

3. The method according to claim 2, comprising at least one of identifying the first operating angular switching position, and identifying the second operating angular switching position; wherein the first or second operating angular switching position is identified by at least one of connecting the first stator ground contact member to a current source at a DC voltage level, and measuring first current value through the first stator ground contact member; and connecting the second stator ground contact member to a current source at a DC voltage level, and measuring second current value through the second stator ground contact member.

4. The method according to claim 1 , comprising rotating the rotor part in relation to the stator part by accessing the rotor part through a hole in the stator part in axial direction of the rotor part.

5. The method according to claim 1 , comprising remotely controlling the rotating of the rotor part in relation to the stator part electrically.

6. The method according to claim 1 , comprising in the first operating angular switching position, the first part of the first bridging member being connected to a signal input terminal and the second part of the first bridging member being connected to a signal output terminal, the first part of the second bridging member being connected to a power combiner and the second part of the second bridging member being to a power combiner or a terminating resistor.

7. The method according to claim 1 , comprising in the second operating angular switching position, the first part of the first bridging member being connected to a signal input terminal and the second part of the first bridging member being connected to a power combiner, the first part of the second bridging member being connected to a signal output terminal and the second part of the second bridging member being connected to a power combiner or a terminating resistor.

8. The method according to claim 6 or 7, comprising transferring twice as much power through the second bridging contact member as through the first bridging contact member; or transferring no power through the second bridging contact member while transferring power through the first bridging contact member.

9. A rotary contact switching device characterized by a stator part comprising stator lead contact members and one or more stator ground contact members; and a rotor part comprising electrically conducting bridging contact members having a first part and a second part, and at least one electrically conducting shielding member; wherein the at least one electrically conducting shielding member is arranged between bridging contact members; and wherein the bridging contact members are each arranged to make electrical contact with two stator lead contact members, and the at least one electrically conducting shielding member makes electrical contact with at least one stator ground contact member of the stator part, when the rotor part is set in the stator part in one of its angular switching positions; where the contact switching device is a multi-pole contact switching device.

10. The rotary multi-pole contact switching device according to claim 9 comprising a first part of the at least one electrically conducting shielding member making electrical contact with a first stator ground contact member in the first operating angular switching position; the first part of the electrically conducting shielding member making electrical contact with a second stator ground contact member in the second operating angular switching position; and a second part of the electrically conducting shielding member making electrical contact with a stator ground contact member in the first and second operating angular switching positions.

11. The rotary multi-pole contact switching device according to claim 9 wherein the stator part comprises a surface-penetrating hole positioned in a surface in a plane intersecting an imaginary axis around which the rotor part revolves and which axis is orthogonal to the intersecting plane; and the rotor part comprises drive or socket means accessible through the hole.

12. The rotary multi-pole contact switching device according to claim 9 wherein the bridging contact members are arranged in recesses in an electrically isolating body of the rotor part, wherein the recesses each comprises a convexity centered in a resulting area at the depth of the recess.

13. The rotary multi-pole contact switching device according to claim 9 wherein the rotor part comprises a top rotor part being flexibly connected to a contact rotor part and the stator part; a spring member between the contact rotor part and the top rotor part, wherein the spring member exercises a contact pressure between the first part of a first bridging contact member and a first stator lead contact member and between the second part of a first bridging contact member the second part of the bridging contact member.

14. The rotary multi-pole contact switching device according to claim 13 wherein the top rotor part is electrically conducting at least on a side facing opposite to the contact rotor part.

15. The rotary multi-pole contact switching device according to claim 13 comprising a motor part.

16. The rotary multi-pole contact switching device according to claim 13, wherein the motor part is connected to the shielding member of the contact rotor part.

17. The rotary multi-pole contact switching device according to claim 9 wherein stator part comprises convexities on a surface extended in direction perpendicular to the imaginary axis of revolving of the rotor part and that the rotor part has corresponding indents in a surface extended in direction perpendicular to the imaginary axis of revolving of the rotor part and facing the surface of the stator part extended in direction perpendicular to the imaginary axis of revolving the top rotor part.

18. The rotary multi-pole contact switching device according to any of claims 9-17, wherein the contact switch is a radio frequency power transfer switch of Surface Mount Technology.

19. Use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner characterized in that the power transfer switch is a rotary multi-pole contact switching device in any of claims 9-18; a first stator lead contact member of the power transfer switch is connected to a circuit input; a second stator lead contact member of the power transfer switch is connected to a power combiner input; a third stator lead contact member of the power transfer switch is connected to a circuit output; and a fourth stator lead contact member of the power transfer switch is connected to an output of the power combiner or a terminating resistor.

20. The use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner according to claim 19, wherein the power transfer switch is mounted on a PCB and wherein the PCB is provided with a hole under the stator part of the power transfer switch corresponding to a hole in the stator part of the power transfer switch on a side facing the PCB when mounted.

21. The use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner according to claim 20, wherein the power transfer switch is arranged for electric motor control.

22. The use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner according to claim 19 wherein, in a first mode of operation, the first stator lead contact member is connected to the third stator lead contact member across a first bridging contact member comprising a first part in electrical contact with the first stator lead contact member and a second part in electrical contact with the second stator lead contact member; and the second stator lead contact member is connected to the fourth stator lead contact member across a second bridging contact member comprising a first part in electrical contact with the second stator lead contact member and a second part in electrical contact with the fourth stator lead contact member.

23. The use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner according to claim 19 wherein, in a second mode of operation, the first stator lead contact member is connected to the second stator lead contact member across a first bridging contact member comprising a first part in electrical contact with the second stator lead contact member and a second part in electrical contact with the first stator lead contact member; and the third stator lead contact member is connected to the fourth stator lead contact member across a second bridging contact member comprising a first part in electrical contact with the fourth stator lead contact member and a second part in electrical contact with the third stator lead contact member.

24. The use of a power transfer switch in a radio frequency transmitter unit circuit comprising a power combiner according to any of claims 1 -23 wherein a first input of the power combiner is connected to a second stator lead contact member of a first power transfer switch; a second input of the power combiner is connected to a second stator lead contact member of a second power transfer switch; a first output of the power combiner is connected to a fourth stator lead contact member of the first power transfer switch; a terminating resistor is connected to a fourth stator lead contact member of the second power transfer switch and a second output of the power combiner is connected to a terminating resistor.

25. System product of switching radio frequency power comprising an EMC enclosure characterized by at least one rotary multi-pole contact switching device in any of claims 9-18; the rotor part of the at least one rotary multi-pole contact switching device comprising a top rotor part which is electrically conducting at least on a side facing opposite to the contact rotor part of the rotary multi-pole contact switching device; the top rotor part comprising a recess on the side facing opposite to the contact rotor part of the rotary multi-pole contact switching device; the EMC enclosure comprising a penetrating hole positioned corresponding to the location of the at least one rotary multi-pole contact switching device housed under the EMC enclosure; and an electrically conducting dust and water resistant seal; wherem the inner surface of the EMC enclosure and the at least one rotary multi-pole contact are in mechanical and electrical contact with the conducting surface of the top rotor part by means of the electrically conducting dust and water resistant seal.

26. The system product of switching radio frequency power comprising an EMC enclosure according to claim 25, wherein the recess of the top rotor part is a circle-shaped recess.

27. The system product of switching radio frequency power comprising an EMC enclosure according to claim 25, wherein the inner side of the EMC enclosure exercises an axial force on the seal and the top rotor part of the rotary multi-pole contact switching device in direction towards the stator part.

28. The system product of switching radio frequency power comprising an EMC enclosure according to claim 25, wherein the recess of the top rotor part is an elongated recess along a diameter of the top rotor part surface facing in direction opposite to the contact rotor part of the rotary multi-pole contact switching device, the system product comprising a lever attached to the top rotor part of the at least one rotary multi-pole contact switching device, wherem the lever is arranged to fit in the recess of the top rotor part of the at least one rotary multi-pole contact switching device.

29. The system product of switching radio frequency power comprising an EMC enclosure according to claim 25, comprising at least one recess in exterior of the EMC enclosure in proximity of the penetrating hole of the EMC enclosure and extending radially from the center of the penetrating hole.

30. The system product of switching radio frequency power comprising an EMC enclosure according to any of claims 25-29, wherein the system product is a radio frequency transmission system product of two operating modes of different transmission power levels.