JP3920620B2 - Antenna switch module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna switch module used in a mobile communication device such as a mobile phone, and more particularly to an antenna switch module including a surface acoustic wave filter (SAW filter).
[0002]
[Prior art]
Currently, DCS 1.8 GHz band, PCS 1.9 GHz band, and GSM 900 MHz band are well known as frequency bands of communication systems used for mobile communication devices such as mobile phones. A triple-band mobile communication device that can handle all of these frequency bands has been proposed. The mobile communication device incorporates an antenna switch module that transmits and receives these radio waves. Here, an antenna switch module having a conventional configuration corresponding to the triple band will be described below.
[0003]
The antenna switch module A corresponding to the triple band shown in FIG. 5 includes an antenna a, a diplexer b, first to third high-frequency switches c1 to c3, and first to third surface acoustic wave filters (SAW filters) f1 to f1. f3, first and second low-pass filters g1 and g2, and receiving electrodes r1 to r3 and transmitting electrodes t1 and t2 corresponding to the respective frequency bands.
[0004]
Here, a diplexer b is connected to an antenna a that transmits and receives radio waves. The diplexer b serves to demultiplex the received signal into a high frequency received signal (DCS received signal and PCS received signal) and a low frequency received signal (GSM received signal), and each transmitted signal (DCS transmitted signal, PCS transmitted). Signal and GSM transmission signal) to the antenna a.
[0005]
A first high frequency switch c1 is connected to one side of the line not connected to the antenna a of the diplexer b, and a second high frequency switch c2 is connected to the other side. These high-frequency switches c1 and c2 function to separate signals so that a predetermined signal that has passed through the high-frequency switches c1 and c2 is sent only to a predetermined conductive line. That is, it has a function of sending a reception signal received from the antenna a to the receiving electrodes r1 to r3 corresponding to each frequency band and sending a transmission signal sent from the transmitting electrodes t1 and t2 to the antenna a side.
[0006]
Further, a third high frequency switch c3 is connected to the receiving electrodes r1 and r2 side of the first high frequency switch c1. The third high-frequency switch c3 has a function of separating the high-frequency reception signal that has passed through the first high-frequency switch c1 into a DCS reception signal and a PCS reception signal.
[0007]
The first surface acoustic wave filter f1 is connected between the third high-frequency switch c3 and the receiving electrode r1, and the second surface acoustic wave filter f2 is connected between the receiving electrode r2. A third surface acoustic wave filter f3 is also connected between the second high frequency switch c2 and the receiving electrode r3. These surface acoustic wave filters f1 to f3 function to pass only received signals having a specific frequency and attenuate received signals having other frequencies.
[0008]
The first and second low-pass filters g1 and g2 are connected between the first high-frequency switch c1 and the transmission electrode t1, and between the second high-frequency switch c2 and the transmission electrode t2. That is, the transmission signal sent from the transmission electrode t1 passes through the first low-pass filter g1 and then sent to the first high-frequency switch c1, and the transmission signal sent from the transmission electrode t2 passes through the second low-pass filter g2. It is sent to the second high frequency switch c2. The transmission signal is separated to the antenna a side by the high frequency switches c1 and c2.
[0009]
By the way, as the configuration of the above-described third high-frequency switch c3, the following configuration is common.
For example, as shown in FIG. 6, when the received signal received by the antenna a is separated to the receiving electrode r2, the voltage is applied to the voltage terminal VC by a voltage control circuit (not shown) connected to the voltage terminal VC. Is applied to turn on the diodes D and D ′. In such a state, the resonant element LC is grounded and thus resonates, and the impedance on the receiving electrode r1 side is increased as viewed from the first high frequency switch c1. By generating such a state, transmission to the receiving electrode r1 side is blocked and a signal is sent to the receiving electrode r2 side. On the other hand, when the received signal is separated to the receiving electrode r1, the application of the voltage is stopped, the diodes D and D ′ are turned off, and the signal is sent to the receiving electrode r1.
[0010]
The antenna switch module A generally has a multilayer configuration in which a plurality of dielectric layers each having a predetermined circuit pattern are laminated and the laminated body is fired. Further, the surface acoustic wave filter f used for the antenna switch module A and the chip components such as the diode D are mounted on the uppermost surface of the laminate.
[0011]
[Problems to be solved by the invention]
As described above, the third high-frequency switch that separates high-frequency reception signals (DCS reception signals and PCS reception signals) including adjacent frequency bands into respective reception signals is based on the cooperation of a diode, a resonant element, a voltage control circuit, and the like. Realized.
[0012]
However, with such a configuration, since the received signal passes through a plurality of switches, there is a problem that an insertion loss of the received signal increases. Furthermore, since it is necessary to apply a voltage by a voltage control circuit to generate a high impedance state, there is a problem that power consumption increases and the number of parts increases. These problems become a major obstacle to improving the performance of mobile communication devices. In addition, since such a diode is mounted on the uppermost surface of the antenna switch module formed by laminating a plurality of dielectric layers, there is a limit to the miniaturization of the antenna switch module.
Accordingly, an object of the present invention is to provide an antenna switch module that can solve these problems.
[0013]
[Means for Solving the Problems]
The present invention includes a plurality of reception electrodes connected to an antenna and outputting a reception signal from the antenna, a transmission electrode outputting a transmission signal to the antenna, a reception signal from the antenna toward the reception electrode, The switch unit includes a switch unit that cuts a transmission signal from the transmission electrode to the antenna side, a phase matching circuit that includes a plurality of phase matching circuit elements having specific frequency characteristics, and a plurality of surface acoustic wave filters. of the reception electrode side, comprising a plurality of phase matching circuit element that will be connected in parallel with each other, the inductor element L or a capacitor C is one side is grounded, between each phase matching circuit element and the switch unit, the switch unit phase matching circuit formed by connecting in common line side is connected, and the surface acoustic wave filters each phase matching circuit elements are connected, further the surface acoustic wave filters It is an antenna switch module, wherein the wave electrodes are respectively connected.
[0014]
As described above, by providing a phase matching circuit including a plurality of phase matching circuit elements having specific frequency characteristics connected between the switch unit and the receiving electrode, a plurality of receptions having different frequencies from each other are provided. The signal can be divided into predetermined lines. The switch unit may be a high-frequency switch having a diode and a resonant element as main components, or a switch made of a GaAs element.
[0015]
The present invention is also connected to the antenna , connected to the antenna, first, second and third receiving electrodes for outputting a reception signal from the antenna, a transmission electrode for outputting a transmission signal to the antenna, A diplexer for demultiplexing a received signal, and first and second switch units connected to the diplexer, for separating the received signal from the antenna to the receiving electrode side, and separating the transmitted signal from the transmitting electrode to the antenna side; A phase matching circuit including first and second phase matching circuit elements each having a specific frequency characteristic; and first, second, and third surface acoustic wave filters; e Bei the first and second phase matching circuit elements are connected in parallel, the inductor element or a capacitor one side is grounded, between the first and second phase matching circuit element and the first switch unit, First Tsu is phase matching circuit formed by connecting in common line Ji portion side connection and first elastic surface wave filter to the first phase matching circuit element, the second phase matching circuit element second elastic surface wave filters, respectively Connected to the first and second surface acoustic wave filters, respectively, and a third surface acoustic wave filter is connected to the second switch part, An antenna switch module, wherein a third receiving electrode is connected to a third surface acoustic wave filter.
[0016]
With this configuration, it is possible to separate three transmission / reception signals having different frequency bands from each other into a predetermined line. Therefore, an antenna switch module capable of supporting a triple band can be obtained.
[0017]
A strip line can be proposed as the phase matching circuit element of the phase matching circuit. The strip line length depends on the input impedance of the surface acoustic wave filter, and is set to have a frequency characteristic that provides a high impedance to a predetermined received signal.
[0018]
Further, the phase matching circuit element may be a capacitor or an inductor element.
[0019]
The multilayer antenna switch module includes a plurality of dielectric layers on which a predetermined circuit pattern is formed, and the plurality of dielectric layers includes a dielectric layer on which a phase matching circuit pattern of a phase matching circuit is formed. Proposed configurations are proposed. In this way, the antenna switch module can be miniaturized by providing the phase matching circuit in the multilayer antenna switch module.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
An antenna switch module 1 according to the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, when receiving a reception signal, the antenna switch module 1 receives a radio wave by the antenna 2 and separates the signal into a DCS reception signal, a PCS reception signal, or a GSM reception signal by the diplexer 3. In this configuration, each signal is further separated by the first and second switch sections 4 and 5 toward the receiving electrodes 15 to 17 and sent to the receiving electrodes 15 to 17 corresponding to the respective frequency bands. On the other hand, when transmitting a transmission signal from each of the transmission electrodes 18 and 19, the first and second low-pass filters 20 and 21 are passed through, respectively, and the first and second switch units 4 and 5 are connected to the antenna 2 side. And is transmitted from the antenna 2 to the outside via the diplexer 3. Each component will be described in detail below. In the present embodiment, a high-frequency switch having a diode D and a resonant element LC as main components is used as the switch units 4 and 5.
[0021]
A diplexer 3 is connected to the DCS, PCS, and GSM shared antenna 2 that receives signals from the outside. The diplexer 3 includes a high-pass filter 11 and a low-pass filter 12, and the reception signal received by the antenna 2 is a high-frequency reception signal (DCS reception signal, PCS reception signal) or a low-frequency reception signal (by this filter function). Each transmission signal (DCS transmission signal, PCS transmission signal, or GSM transmission signal) demultiplexed into (GSM reception signal) and transmitted from the transmission electrodes 18 and 19 is transmitted to the antenna 2.
[0022]
The first switch unit 4 is connected to the high pass filter 11 side of the diplexer 3. The first switch unit 4 is composed of a diode D, a resonant element LC, a voltage terminal VC to which a voltage control circuit is connected, and the like, and these signals cooperate to generate a received signal (DCS received signal or PCS received signal). One transmission signal (DCS transmission signal or PCS transmission signal) is cut to the antenna 2 side toward the receiving electrode 15 for PC or the receiving electrode 16 for PCS.
[0023]
On the other hand, the second switch unit 5 is connected to the low pass filter 12 side of the diplexer 3. Similar to the first switch unit 4, the second switch unit 5 is composed of a diode D or the like, and the reception signal (GSM reception signal) is directed to the GSM reception electrode 17 side, while the transmission signal (GSM transmission signal) is an antenna. Divided into two sides.
[0024]
A first low-pass filter 20 is connected to the transmission electrode 18 side of the first switch unit 4, and a DCS / PCS shared transmission electrode 18 is connected to the first low-pass filter 20. That is, when a DCS or PCS transmission signal is output from the transmission electrode 18, the first low-pass filter 20 attenuates an unnecessary frequency and then transmits the signal to the first switch unit 4.
[0025]
Similarly, the second low-pass filter 21 is also connected to the transmission electrode 19 side of the second switch unit 5, and the GSM transmission electrode 19 is connected to the second low-pass filter 21. Therefore, when the GSM transmission signal is output from the GSM transmission electrode 19, the GSM transmission signal is transmitted to the second switch unit 5 after passing through the second low-pass filter 21.
[0026]
A third surface acoustic wave filter 8 is connected between the second switch unit 5 and the GSM receiving electrode 17. That is, the GSM reception signal that has been separated to the receiving electrode 17 side by the second switch unit 5 is sent to the receiving electrode 17 after the unnecessary frequency is attenuated by the third surface acoustic wave filter 8.
[0027]
Next, the phase matching circuit 10 which is the main part of the present invention, and the first and second surface acoustic wave filters 6 and 7 connected thereto will be described.
A phase matching circuit 10 including two phase matching circuit elements having different frequency characteristics is connected to the receiving electrodes 15 and 16 side of the first switch unit 4 described above. The phase matching circuit 10 has a configuration in which phase matching circuit elements are connected in parallel with each other.
[0028]
Here, in this embodiment, strip lines 10a and 10b are proposed as the phase matching circuit elements. The strip line 10a depends on the input impedance of the first surface acoustic wave filter 6, and is configured to have a high impedance with respect to the PCS reception signal. Similarly, the strip line 10b depends on the input impedance of the second surface acoustic wave filter 7, and is configured to have a high impedance with respect to the DCS reception signal.
[0029]
Here, the line length of the DCS strip line 10a is set so as to have a frequency characteristic having a high impedance with respect to the PCS reception signal so as to block the PCS reception signal (1930 to 1990 MHz). On the other hand, the line length of the PCS strip line 10b is set so as to have a frequency characteristic having a high impedance with respect to the DCS reception signal so as to block the DCS reception signal (1805 to 1880 MHz).
[0030]
By the way, the phase matching pattern of the phase matching circuit 10 including the strip lines 10a and 10b may be a spiral (spiral) pattern or a meander (meandering) pattern. Further, such a phase matching circuit 10, each strip line 10a, in order to shorten as much as possible 10b line length of each strip line 10a which is connected in parallel to each other, between said and 10b first switch section 4 A configuration in which the inductor element L or the capacitor C whose one side is grounded is connected to the common line on the first switch unit 4 side . FIG. 1 shows a configuration in which an inductor element L is connected.
[0031]
Further, the first surface acoustic wave filter 6 is connected to the DCS stripline 10a, and the second surface acoustic wave filter 7 is connected to the PCS stripline 10b. With this configuration, unnecessary frequencies of each received signal are attenuated and sent to the receiving electrodes 15 and 16 corresponding to each frequency band.
[0032]
Further, the phase matching circuit element of the phase matching circuit 10 may have another configuration instead of the above configuration. For example, an inductor element L is proposed as a phase matching circuit element, and the phase matching circuit 10 including two inductor elements L and L connected in parallel to each other may be used (see FIG. 3). For example, FIG. 3 b is two inductor element L, with L is connected in parallel to each other, in order to shorten the line length of the inductor elements L, L, a capacitor C is that one side is grounded, the first The structure connected to the common line by the side of the 1st switch part 4 between the switch parts 4 is shown. 3B shows a configuration in which two inductor elements L and L are connected in parallel to each other, and capacitors C and C having one side grounded are connected to the first switch section 4 side of each inductor element L and L, respectively. Show.
[0033]
Further, a capacitor C is proposed as a phase matching circuit element, and two capacitors C and C connected in parallel may be provided (see FIG. 4). For example, FIG. 4A shows a configuration in which two capacitors C and C are connected in parallel to each other, and one inductor element L whose one side is grounded is connected to the first switch unit 4 side. FIG. 4B shows a configuration in which two capacitors C and C are connected in parallel to each other, and inductor elements L and L whose one side is grounded are connected to the first switch portion 4 side of each capacitor C and C, respectively. ing.
[0034]
As shown in FIG. 2, the antenna switch module 1 described above preferably has a configuration in which a plurality of dielectric layers 30 each having a predetermined circuit pattern 31 are stacked and the stacked body 32 is fired. is there. In the present invention, the plurality of dielectric layers 30 include those having the phase matching circuit pattern of the phase matching circuit 10. That is, the multilayer antenna switch module 1 includes the phase matching circuit 10.
[0035]
Further, a chip component (such as a diode D or a surface acoustic wave filter f) is mounted on the top surface of the laminate 32. Here, since the present invention has a configuration using the phase matching circuit 10 instead of the high-frequency switch c3 including the diode D having the conventional configuration, the number of chip components mounted on the uppermost surface of the multilayer body 32 can be reduced. it can. As a result, the number of parts of the antenna switch module 1 is reduced and the antenna switch module 1 can be downsized.
[0036]
Each circuit pattern 31 formed on the dielectric layer 30 is an inductor element L or a capacitor C). The circuit pattern 31 is preferably formed by a known screen printing method.
[0037]
【The invention's effect】
Since the antenna switch module according to the present invention has a configuration in which a phase matching circuit having a plurality of phase matching circuit elements is connected and a signal in a specific frequency band is separated into a predetermined line, a diode, a voltage control circuit, etc. This eliminates the need for a switch unit that uses, and can eliminate an insertion loss that occurs when a received signal passes through the switch unit, and also solves the problem of increased power consumption. In addition, since it is not necessary to provide a separate voltage control circuit, it is possible to reduce the number of components, which can contribute to downsizing of the antenna switch module and reduction in manufacturing cost.
[0038]
When the first and second switch units connected to the diplexer are provided and the phase matching circuit is connected to the first switch unit, the antenna switch module is compatible with a triple band. It becomes possible.
[0039]
In addition, when a strip line, a capacitor, or an inductor element is used as the phase matching circuit element, a signal in a specific frequency band can be suitably divided into predetermined lines.
[0040]
Further, when the phase matching circuit is built in the multilayer antenna switch module, it is not necessary to mount chip parts on the outer surface of the antenna switch module, and the antenna switch module can be downsized as a whole.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of an antenna switch module 1 according to the present invention.
FIG. 2 is a longitudinal sectional view of a laminated body 32. FIG.
FIG. 3 is a block circuit diagram showing another embodiment of the phase matching circuit 10 respectively.
4 is a block circuit diagram showing another embodiment of the phase matching circuit 10, respectively. FIG.
FIG. 5 is a conceptual diagram showing a configuration of an antenna switch module A having a conventional configuration.
FIG. 6 is a block circuit diagram of a third high frequency switch c3 of the antenna switch module A having a conventional configuration.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Antenna switch module 2 Antenna 3 Diplexer 4, 5 1st and 2nd switch part 6, 7, 8 1st-3rd surface acoustic wave filter 10 Phase matching circuit 10a, 10b Strip line 15 DCS receiving electrode 16 PCS receiving electrode 17 GSM receiving electrode 18 DCS, PCS shared transmitting electrode 19 GSM transmitting electrodes 20, 21 First and second low-pass filter 30 Dielectric layer 31 Circuit pattern 32 Laminate C Capacitor L Inductor Element LC Resonant element

Claims (6)

A plurality of receiving electrodes that are connected to the antenna and output a reception signal from the antenna, a transmission electrode that outputs a transmission signal to the antenna, a reception signal from the antenna to the reception electrode side, and from the transmission electrode A switching unit that cuts the transmission signal to the antenna side, a phase matching circuit that includes a plurality of phase matching circuit elements having specific frequency characteristics, and a plurality of surface acoustic wave filters,
The reception electrode side of the switching unit, comprising a plurality of phase matching circuit element that will be connected in parallel with each other, the inductor element L or a capacitor C one end is grounded, between the switch unit and the phase matching circuit elements The phase matching circuit connected to the common line on the switch side is connected,
A surface acoustic wave filter is connected to each phase matching circuit element, and a receiving electrode is connected to each surface acoustic wave filter. First, second and third receiving electrodes connected to an antenna for outputting a received signal from the antenna, transmitting electrodes for outputting a transmitted signal to the antenna, and demultiplexing the received signal connected to the antenna A first diplexer, a first switch unit connected to the diplexer, for separating a reception signal from an antenna to a reception electrode side, and a transmission signal from a transmission electrode to an antenna side, and a specific frequency characteristic. A first phase matching circuit including first and second phase matching circuit elements, and first, second and third surface acoustic wave filters,
The first switching unit, e Bei the first and second phase matching circuit elements are connected in parallel to each other, an inductor element or a capacitor one side is grounded, the the first and second phase matching circuitry first A phase matching circuit connected to the common line on the first switch part side is connected with one switch part ,
The first surface acoustic wave filter is connected to the first phase matching circuit element, the second surface acoustic wave filter is connected to the second phase matching circuit element, and the first and second surface acoustic wave filters are respectively connected to the first and second surface acoustic wave filters. A second receiving electrode is connected, a third surface acoustic wave filter is connected to the second switch portion, and a third receiving electrode is connected to the third surface acoustic wave filter. A featured antenna switch module. The phase matching circuit is:
The first and second phase matching circuit elements are strip lines, and an inductor element whose one side is grounded is connected to a common line on the first switch unit side between each strip line and the first switch unit. it is made of Te claim 1 or claim 2 antenna switch module according. The phase matching circuit is:
The first and second phase matching circuit elements are capacitors, and an inductor element whose one side is grounded is connected to a common line on the first switch unit side between each capacitor and the first switch unit. in the antenna switch module according to claim 1 or claim 2, wherein ones. The phase matching circuit is:
The first and second phase matching circuit elements are inductor elements, and a capacitor grounded on one side is connected to a common line on the first switch part side between each inductor element and the first switch part. that is in a claim 1 or claim 2 antenna switch module according.   A multilayer antenna switch module including a plurality of dielectric layers on which a predetermined circuit pattern is formed, and the plurality of dielectric layers include a dielectric layer on which a phase matching circuit pattern of a phase matching circuit is formed. The antenna switch module according to any one of claims 1 to 4, wherein the antenna switch module is one.

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