JP2602121B2 - Filter and radio using the same - Google Patents

Description

The present invention relates generally to radio frequency (RF) signal filters, and more particularly to dual radio transceivers.
rs) for a single block filter for antenna duplexing and antenna switched diversity.

2. Prior Art A prior art single block ceramic filter for antenna switching is shown and described in U.S. Pat. No. 4,742,562. However, such prior art single block ceramic filters do not accommodate antenna switched diversity.

In the past, antenna switched diversity was 800 MHz
It has been used to minimize the effects of signal fading in mobile radio communications systems, which is a problem that is exacerbated in cellular telephone systems with higher operating frequencies. According to the prior art antenna switching diversity mechanism, the receiver is switched from the first antenna to the second antenna in response to detecting the deterioration of the received signal. This is done in prior art cellular telephones by using one transmit filter and two separate receive filters and by switching the input of the cellular telephone handset between the two receive filters, or
This has been done using one transmit filter and one receive filter and switching the input of the receive filter between the two antennas.

However, in both of the previous examples, two separate filters are required.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a single block filter capable of performing both antenna switching and antenna switching diversity in a dual radio transceiver.

It is another object of the present invention to provide a single block filter having electrodes extending at least partially to corresponding resonators for coupling a transmitter and receiver of a wireless transceiver to first and second antennas. Is to provide.

It is yet another object of the present invention to provide a unique coupling electrode that extends at least partially into a corresponding resonator of a single block filter and has a flat portion for coupling a signal thereto.

FIG. 1 is a perspective view of a single block filter 10 embodying the present invention for providing both antenna transmit / receive switching and antenna switched diversity.
A dual radio transceiver (transceiver) 100 including two antennas 142 and 144 coupled to two is shown.
Dual radio transceiver 100 also includes a receiver 130 coupled to speaker 131, a transmitter 132 coupled to microphone 133, a diversity control circuit 101 coupled to antenna 144, and a receiver 130, transmitter 132 and diversity control. Circuit 10
1 includes a microcomputer 134 coupled to and for controlling their operation. Block 130 of transceiver 100,
131, 132, 133 and 134 may be components of any commercially available dual radio transceiver. In the preferred embodiment, transceiver 110 is
0DY, East Argonquin Road 1313, "DY" issued and available by Motorola C & E parts
NATAC Cellular Mobile Phone "is a transceiver shown and described in Motorow Line Instruction Manual 68P81070E40.

In accordance with the present invention, a single block filter 102 is coupled to antennas 142 and 144 to provide antenna duplexing and antenna switched diversity. antenna
142 is coupled to transmitter 132 by filter 102, and antennas 142 and 144 are switchably coupled by filter 102 to receiver 130 by diversity control circuit 101 in response to diversity control signal 137. A microcomputer 134 is coupled to the receiver 130 and monitors the received signal strength indicator (RSSI) signal 135. If the RSSI signal 135 drops in level indicating that the signal being received on one of the antennas 142 or 144 has been degraded by fading or other interference, then the microcomputer 134 will The binary state of diversity control signal 137 is changed to switch 130 to another one of antennas 142 or 144.

Diversity control circuit 101 connects receiver 130 to antenna 142
Diversity control signal 1 to switch between and 144
It includes pin diodes 152 and 162 which are switched in response to 37. When the antenna 144 is selected, the pin diode 152 is switched off and the pin diode 162 is switched on and the pad of the filter 102 is
Couple 118 to RF signal ground. Or antenna 1
If 42 is selected, pin diode 162 is switched off and pin diode 152 is switched on, coupling pad 117 of filter 102 to RF signal ground. Pin diodes 152 and 162 are switched on and off in response to the binary state of diversity control signal 137, ie, the binary 0 state or the binary 1 state.

If diversity control signal 137 has a binary one state, the output of inverter 136 has a binary zero state (low voltage) and the output of inverter 138 has a binary one state.
(High voltage). The binary 1 state of the output of inverter 138 turns on transistor 156.
When the transistor 156 is on (conducting current), the transistor 155 is turned on and applies a bias current to the pin diode 152 via the resistor 151.
Pin diode 152 is switched on (low impedance state) by this bias current, and couples pad 117 and antenna 144 to RF signal ground via capacitor 150. Pad 117 is preferably coupled to capacitor 150 and antenna 144 by a coaxial cable or transmission line. The capacitance 150 and the pin diode 152 are also preferably located as close as practical to the termination A1 of such a coaxial cable. At the same time, the binary 0 state of the output of inverter 136 turns off transistors 166 and 165 and keeps pin diode 162 off (high impedance state). Inductor 163 and capacitor 164 are coupled in parallel with pin diode 162 to resonate the parasitics of pin diode 162 and achieve better open and short circuit conditions.

Conversely, if diversity control signal 137 has a binary 0 state, the output of inverter 136 has a binary 1 state (high voltage) and the output of inverter 138 is 2
It has a binary 0 state (low voltage). The binary 1 state of the output of inverter 136 turns on transistor 166. When the transistor 166 is in the on state (current conducting state), the transistor 165 turns on and applies the bias current to the pin diode 162 via the resistor 161. Pin diode 162 is switched on (low impedance state) by this bias current and couples pad 118 through capacitor 160 to RF signal ground.
Pad 118 is preferably coupled to capacitance 160 by a coaxial cable or, alternatively, a transmission line. It is also preferred that the capacitance 160 and the pin diode 162 be located as close as practical to the termination G of such a coaxial cable. At the same time, the binary 0 state of the output of inverter 138 is
Is turned off, and the pin diode 152 is kept in the off state (high impedance state). Inductor 153 and capacitance 1
Numeral 54 is coupled in parallel with the pin diode 152 to resonate the parasitic components of the pin diode 152 to achieve better open and short circuit conditions.

The filter 102 in FIG. 1 preferably has a high dielectric constant,
This is a dielectric block filter made of low-loss ceramic. The filter 102 may alternatively be partially contained within a housing, such as the housing 280 shown in FIG. 2, such a housing constituting a modularized filter element mounted by soldering or other means. be able to. Filter 102 includes a transmission line resonator formed by elongated holes or holes 103-113 extending from its top surface to its bottom surface. Hall 103-113
Has a substantially rectangular cross section with rounded corners and parallel elongated sides. The bottom and sides of the filter 102 and the inner surfaces of the holes 103-113 are substantially coated over their entire surface with a conductive material. The top surface of filter 102 is covered by a strip of conductive material near its periphery substantially surrounding holes 103-113. Also on the top face is a pad for each hole 103-113, a pad 120 coupled to the transmitter 132 by a coaxial cable (at termination T), by a coaxial cable (at termination R).
Pad 116 coupled to receiver 130, Pad 1 coupled to antenna 142 by coaxial sable (at termination A2)
19. Antenna by coaxial cable (at terminal A1)
Disposed are pad 117 coupled to 144 and capacitance 150, and pad 118 coupled to capacitance 160 (at termination G) by a coaxial cable. The pads for each of the holes 103-113 and the pads 116-120 are similarly constructed of a conductive material covering the top surface of the filter 102.
The pads for the holes 103-113 can be variously shaped to capacitively interconnect with each other and to couple to the surrounding conductive material on the sides of the filter 102. Each of the holes 103-113 essentially functions as a shortened transmission line resonator. In a preferred embodiment, the conductive material covering the face of the filter 102 is plated thereon.

Pad 117 is coupled to RF signal ground and pad 118
If is not grounded, the filter 102
And functions as a duplexer for coupling the transmitter 132 to the antenna 142. Conversely, when pad 118 is coupled to RF signal ground, receiver 130 is coupled to antenna 144 via pad 117, and grounded pad 118 isolates the receiver from antenna 142 and transmits. 132 is antenna 14
Combined into two. The amount of isolation provided by grounding pad 118 increases or decreases the capacitive coupling between pad 118 and the pad for hole 108, thereby increasing the distance between pad 118 and the pad for hole 108. Of the pads 108 and 118, or by any other suitable means. The amount of coupling provided by pad 117 can vary with respect to the pad for hole 107 as well. In other embodiments, pad 118 can be directly coupled to hole 108, or can be part of a pad for hole 108.

Referring now to FIG. 4, there is shown a flow chart of the process used by microcomputer 134 of FIG. 1 to select between antennas 142 and 144.
Upon entering the Start (START) block 402, processing proceeds to block 404 where the guard time flag is checked. If the guard time flag has a binary 1 state, the YES branch is taken to block 408. Block 408
In, a check is made to determine whether the 4 millisecond timer (4MS) has elapsed. If not, a NO branch returns (RETURN) block 420
And return to other tasks. If the 4 ms timer has timed out, a YES branch is taken from block 408 to block 409, where the guard time flag is reset to the binary 0 state. Thereafter, program control proceeds to block 410 as described below.

Returning to block 404, if the guard time flag is 2
If so, the NO branch is taken to block 406, where a check is made to determine if the 10 millisecond timer (10MS) has timed out. If not, the NO branch is taken to return block 420 and returns to another task. If the 10MS timer has timed out, a YES branch is taken from block 406 to block 410,
There, RSSI samples are taken. Block 410 is also reached after the 4MS timer times out from blocks 408 and 409. Microcomputer 134 receives RSSI signal 1
Includes an analog-to-digital converter to take 35 digitized samples. Next, at block 412, a check is made to determine if the RSSI sample is 6 dB below the average RSSI. Average RSSI of last 15
Running average taken by microcomputer 134 over RSSI samples. If RSS
If the I sample is not 6 dB below the average RSSI, a NO branch is taken from block 412 to block 414, where the average RSSI is updated with the current RSSI sample, and a 10MS timer is set for another 10 millisecond time interval. To be restarted. Thereafter, program control returns to block 42
Return to other tasks at 0.

Returning to block 412, if the RSSI sample is the average RSSI
If so, the YES branch is taken to block 416 where the binary state of diversity control signal 137 is
And 144 to switch between. next,
At block 418, the guard time flag is set to the binary 1 state, and the 4MS timer is restarted for a 4 millisecond time interval. The guard time flag is set to sample the RSSI signal 135 four milliseconds after switching between antennas 142 and 144. As a result, the RSSI signal 135 will be re-sampled after 4 milliseconds rather than 10 milliseconds. The sampling period is reduced to ensure that the switched antenna 142 or 144 is receiving the appropriate RF signal. If both antennas 142 and 144 are receiving a poor RF signal, receiver 130 will be switched from one antenna to the other every four milliseconds. Thereafter, program control returns to another task at return block 420.

Referring to FIG. 2, another filter embodying the present invention
202 is shown. Instead of using pads to couple signals there, the filter 202 comprises coupling electrodes 216, 217, 2
18,219 and 220, which at least partially extend into corresponding holes 203,207,208,209 and 213, respectively. The electrodes 216 to 220 are each a dielectric plug 226
Positioned and held in holes 203, 207, 208, 209 and 213 by ~ 230. Plugs 226-230 can be comprised of any suitable dielectric or insulator, such as, for example, ceramic or plastic.
Plugs 226-230 can be retained in holes 203, 207, 208, 209 and 213 by press fit, adhesive, or other suitable means. Plugs 226-230 also have holes 203, 207, 208,
It can also be loosely fitted within 209 and 213 and held therein by a housing 280, in which case the housing 280 extends over the plugs 226-230 and into which the electrodes 216-220 can project. With holes.
Once the housing 280 is mounted by soldering or other suitable means, the filter 202 can be a printed circuit board (not shown) as a modular filter element.
Can be mounted on.

Referring to FIG. 3, a unique coupling electrode 216 is shown, which extends at least partially into a corresponding hole 203 of the filter 202 and has flat portions 316, 317 for coupling signals thereto. have. Electrode 216
Is inserted into a plug 326, which includes a head 226 and a rectangular holding portion 318 for receiving flats 316, 317 of the electrode 216. Electrode 216 can have a varying shape and size to alter the amount of coupling into the resonator provided by hole 203. For example, electrode 216 can have a rectangle 317 or triangle 316. In another embodiment, the electrodes 216 are simply pins. Coupling electrodes 217, 218, 219 and 220 and corresponding plugs 227, 228, 229 and 230 can also be implemented as shown in FIG.

Referring to FIG. 5, there is shown a top view of yet another single block filter 500 embodying the present invention, which has two antenna pads 524 and 526. The embodiment of FIG. 5 makes better use of the separation characteristics of the filter 500. Pad 524 has holes 508 and
Pad 526 is also a strip of conductive material located between holes 509 and 510. Pad 524 is pad 526
Extends from the opposite side of the filter 500. Pad 524
And the width, length and positioning of 526 can be varied to change the coupling to the corresponding holes 508,509 and 509.510, respectively. Pad 526 is antenna terminal A2
Are coupled to resonators 509 and 510. Switch 522 responds to diversity control signal 137 to switch pad 524 to either antenna terminal A1 or antenna terminal A2. Switch 522 can be implemented by one or more traditional reed relays, or by pin diodes and transmission line circuits. Hole 5 of filter 500
The pads for 03-513 capacitively interconnect with each other and have varying shapes to couple to the surrounding conductive material on the sides of the block.

Referring to FIG. 6, there is shown a top view of yet another single block filter 600 embodying the present invention, the filter having two antenna pads 624 and 626. The embodiment in FIG. 6 effectively utilizes the separation characteristics of the filter 600. Pad 624 is a strip of conductive material located between holes 608 and 609, and pad 626 is also a strip of conductive material located between holes 609 and 610. Pad 624 extends from the same side of filter 600 as pad 626.
The width, length and positioning of pads 624 and 626 can be varied to change the coupling to corresponding holes 608,609 and 609,610, respectively. Pad 626 couples antenna terminal A2 to resonators 609 and 610. Switch 62
2 switches pad 624 to either antenna terminal A1 or antenna terminal A2 in response to diversity control signal 137. Switch 622 can be implemented by one or more traditional reed relays or by pin diodes and transmission line circuits. filter
The pads for the 600 holes 603-613 have shapes that vary capacitively to couple to each other and to the surrounding conductive material on the sides of the block.

SUMMARY OF THE INVENTION In summary, a unique single block filter has been described that can provide both antenna duplexing and antenna switched diversity in a dual radio transceiver. This unique single block filter can include a coupling electrode and a housing to provide a modular filter element. Further, the single-block filter may include a unique coupling electrode that extends at least partially into its corresponding resonator and has a flat portion for coupling signals thereto. The novel single block filter and the novel coupling electrode according to the present invention
It can be suitably used for applications where filtering, antenna transmission / reception switching, and / or antenna diversity are desired.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a dual radio transceiver shown in perspective and including two antennas coupled to a single block filter embodying the present invention. FIG. 2 is a perspective view showing another single block filter embodying the present invention. FIG. 3 is a perspective view of a coupling device used in the single block filter of FIG. FIG. 4 is a flowchart showing the process used by the microcomputer in FIG. 1 to make a selection between two antennas coupled to a dual radio transceiver. FIG. 5 is a top view of yet another single block filter embodying the present invention having two antenna electrodes. FIG. 6 is a top view of yet another single block filter embodying the present invention having two antenna electrodes. 100: Dual radio transceiver, 101: Diversity control circuit, 102: Single block filter, 130: Receiver, 131: Speaker, 132: Transmitter, 133: Microphone, 134: Microcomputer, 142,144: Antenna, 152, 162: Pin diode, 103, 104,…, 113: hole, 116, 117,…, 120: pad, 202: single block filter, 203, 204,…, 213: hole, 216, 217, 218, 219, 220: coupling electrode, 226,…, 230: dielectric plug, 280 : Housing, 316, 317: Flat part, 318: Hold part, 326: Plug.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Richard S. Comrush, Hitching Post Lane, Schaumburg, 60195, Illinois, United States 2128 (56) References JP-A-63-174402 (JP, A) Showa 61-179603 (JP, A) Actually open Showa 63-40009 (JP, U)

Claims (15)

(57) [Claims] A transmitter coupled to the first antenna and a receiver coupled to the first antenna;
4) In response to the control signal from 4), a filter for coupling the receiver to a second antenna, the filter having a head, a bottom and a side face and each from the head face. At least first, second, third, fourth and fifth holes extending in a bottom surface and aligned with one another, wherein the bottom and side surfaces and the five holes are substantially conductive. A dielectric block covered with a material; first coupling means for coupling the transmitter to the first hole; second coupling means for coupling the first antenna to the second hole; Third coupling means for coupling the third hole to a signal ground in response to the control signal; and third coupling means for coupling the fourth hole to the second antenna in response to the control signal. 4, the coupling means, and the fifth hole Fifth coupling means for coupling to the receiver. 2. The filter according to claim 1, wherein said third coupling means includes switching means for switching said third hole to signal ground in response to said control means. 3. The filter according to claim 2, wherein said switching means includes a pin diode means. 4. The apparatus according to claim 1, wherein said fourth coupling means includes switching means for switching said fourth hole between said second antenna and signal ground in response to said control signal. Item 2. The filter according to Item 1. 5. The filter according to claim 4, wherein said switching means includes a pin diode means. 6. A first antenna, a second antenna, a transmitter having an output, a receiver having an input, a control means coupled to at least the receiver and generating a control signal, And a filter coupling the receiver to the first antenna and coupling the signal to a second antenna in response to a control signal, the filter comprising: a head, a bottom, and a side. And having at least first, second, third, fourth and fifth holes each extending from the head surface to the bottom surface and aligned with one another, the bottom and side surfaces and the five A dielectric block in which the holes are substantially covered with a conductive material; first coupling means for coupling the transmitter to the first hole; coupling the first antenna to the second hole Second tie to Third coupling means for coupling the third hole to signal ground in response to the control signal; for coupling the fourth hole to the second antenna in response to the control signal A fourth coupling means, and a fifth coupling means for coupling the fifth hole to an input of the receiver. 7. A radio according to claim 6, wherein said third coupling means includes switching means for switching said third hole to signal ground in response to said control signal. 8. The wireless device according to claim 7, wherein said switching means includes a pin diode means. 9. The system according to claim 1, wherein said fourth coupling means includes switching means for switching said fourth hole between said second antenna and signal ground in response to said control signal. Item 7. The wireless device according to Item 6. 10. The wireless device according to claim 9, wherein said switching means includes a pin diode means. 11. The receiver includes means for generating an output signal having a magnitude related to the strength of the signal received by the receiver, and the control means couples to the output signal of the receiver. And if the output signal of the receiver has at least the same magnitude as the predetermined magnitude,
Generating the control signal in one of a binary 0 state and a binary 1 state and outputting the control signal if the output signal of the receiver has a magnitude smaller than the predetermined magnitude; 7. The radio according to claim 6, further comprising processing means for generating a control signal for the other of the 0 state and the binary 1 state. 12. The apparatus according to claim 11, wherein said processing means samples the output of said receiver at least at predetermined time intervals and thereafter generates said binary 0 or binary 1 state control signal. The described radio. 13. A receiver coupled to a first antenna and a receiver coupled to said first antenna, and responsive to a control signal from a calculation control means (134) to couple said receiver to a second antenna.
A filter having a head, a bottom, and a side surface, each extending from the head surface to the bottom surface and being aligned with one another. A derivative block having 2, 3, 4, and 5 holes, wherein the bottom and side surfaces and the 5 holes are substantially covered by a conductive material; First coupling means extending within the first hole, insulated from the conductive material therein, for coupling the first hole to the transmitter, at least partially within the second hole; Second coupling means extending insulated from the conductive material in the hole and having an electrode for coupling the second hole to the first antenna; at least partially within the third hole Third coupling means extending insulated from the conductive material in the hole and having an electrode for coupling the third hole to signal ground in response to the control signal; at least partially the fourth coupling means. Fourth coupling means extending into the hole, insulated from the conductive material in the hole, and having an electrode for coupling the fourth hole to a second antenna in response to the control signal; Fifth coupling means extending in the fifth hole insulated from the conductive material in the hole and having an electrode for coupling to the fifth hole and the receiver. The featured filter. 14. A first antenna, a second antenna, a transmitter having an output, a receiver having an input, a control means coupled to at least the receiver and generating a control signal, And a filter for coupling the receiver to the first antenna and coupling the receiver to a second antenna in response to a control signal, comprising: a head, a bottom, and A dielectric block having at least first, second, third, fourth and fifth holes each having a side surface portion and extending from the head surface to the bottom surface and aligned with each other, The bottom and side surfaces and the five holes are substantially covered by a conductive material, and extend at least partially into the first hole and insulated from the conductive material in the hole. First coupling means for coupling a first hole to the transmitter, at least partially extending into the second hole, insulated from a conductive material in the hole, and connecting the second hole to the transmitter. Second coupling means having an electrode for coupling to the first antenna, at least partially extending into the third hole, insulated from the conductive material in the hole, and controlling the third hole Third coupling means having an electrode for coupling to a signal ground in response to a signal, the fourth hole extending at least partially into the fourth hole insulated from a conductive material in the hole; Fourth coupling means having an electrode for coupling to a second antenna in response to the control signal; and at least partially within the fifth hole and insulated from a conductive material in the hole. And a fifth coupling means having an electrode for coupling to the fifth hole and the receiver. 15. An antenna, a transmitter having an output, a receiver having an input, coupling the transmitter to a first antenna and coupling the receiver to the first antenna, and responsive to a control signal. A filter for coupling the receiver to the second antenna, the filter having a head, a bottom, and a side surface, each extending from the head surface to the bottom surface and aligned with one another. A dielectric block having at least first, second, third, fourth and fifth holes, wherein the bottom and side surfaces and the five holes are substantially covered with a conductive material. A first coupling means for coupling the output of the transmitter to the first hole; a second coupling means for coupling the first antenna to the second hole
Coupling means for coupling the third hole to a signal ground.
Coupling means for coupling the fourth hole to the second antenna; and fifth coupling means for coupling the fifth hole filter to an input of the receiver. A wireless device, comprising: