JP2006340268A - Transmission/reception circuit and wireless communication device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission/reception circuit and a wireless communication device which can make a circuit scale small, can extensively reduce a circuit loss, and can operate in a wide band. <P>SOLUTION: The wireless communication devices each has a pass band different from each other, and includes a plurality of reception filters which filter wireless signals received by a reception antenna, a switch SW2 which selects one of the wireless signals from among the wireless signals outputted from a plurality of reception filters, and a low noise amplifier which amplifies a low noise of the wireless signal outputted from the switch SW2. An antenna impedance adjusting portion is connected to a feeding point of the reception antenna, and adjusts an antenna impedance so as to make an antenna impedance substantially minimum in a pass bandwidth of a reception filter selected when the received antenna is observed at the feeding point according to the selection of the wireless signal by the switch SW2 and to be coincident with an input/output impedance of a reception filter selected and an input impedance of the low noise amplifier. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multiband transmission / reception circuit used in, for example, a GSM system, a WCDMA system, a CDMA2000 system, and the like, and a wireless communication apparatus using the same.

  In recent years, mobile phones having a multi-band wireless function capable of transmitting and receiving at a plurality of frequencies are becoming a global standard in order to support the GSM system and the CDMA system in various parts of the world. In order to construct a system that spans a plurality of frequencies, a wideband design for expanding the frequencies that can be covered by the corresponding high-frequency components has been demanded.

  In order to realize such a wireless device, in Patent Document 3, broadband transmission / reception is realized with the configuration shown in FIG. FIG. 14 is a block diagram showing a configuration of a wireless communication apparatus according to the first conventional example.

  FIG. 14 shows an active load adjustment system of a power amplifier (PA) constituting a part of a transmitter of a wireless communication apparatus. In the load adjustment system, the high frequency signal input to the high frequency input terminal 1046 is transmitted to the antenna via the variable amplifier 1030, the transmission power amplifier 1032, the static matching circuit 1034, the variable impedance network 1036, and the output terminal 1048. Is output and emitted. The control processor 1038 generates a control signal by referring to the control value in the memory 1040 based on the input transmission power level signal, frequency, and battery voltage, and performs load control A / D conversion on the generated control signal. By outputting to the variable impedance network 1036 via the device 1042 and the level shift circuit 1044. Controls variable impedance network 1036. Here, good transmission characteristics can be obtained by maintaining the output impedance matching of the transmission power amplifier 1032 in an optimal state.

JP 2001-068942 A. Warren L. Stutzman et al., "Antenna Theory And Design", John Wiley & Sons, Inc., New York, pp.175-179, 1998.

  However, in the configuration of the conventional example as described above, it is necessary to increase the width of the variable impedance when the frequency change range is large, and the circuit scale is large, so that the loss also increases. In addition, the frequency band that can be matched due to the frequency dependence of the coil and capacitor of the matching circuit used when matching the low impedance of the output transistor of the transmission power amplifier in accordance with the characteristic impedance (for example, 50Ω) of the antenna is extremely high. There was a problem that it would be narrow.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, to reduce the circuit scale as compared with the conventional example, to greatly reduce the circuit loss, and to operate in a wide band, and a radio using the same It is to provide a communication device.

A receiving circuit according to a first invention has a predetermined antenna impedance and receives a radio signal;
A plurality of reception filters each having a predetermined input / output impedance, each having a different pass band, and outputting a radio signal received by the receiving antenna through band pass filtering;
First switching means for selecting and outputting one of the radio signals output from the plurality of reception filters;
In a receiving circuit having a predetermined input impedance, and a low noise amplifying means for amplifying and outputting a radio signal output from the switching means by low noise,
The antenna impedance when the receiving antenna is viewed at the feeding point is connected to the feeding point of the receiving antenna according to the selection of the radio signal by the first switching means in the pass band of the selected receiving filter. And adjusting means for adjusting the antenna impedance so that it is substantially the minimum value and substantially matches the input / output impedance of the selected receiving filter and the input impedance of the low noise amplifying means. To do.

In the receiving circuit, the adjusting means includes
A plurality of capacitors having one end grounded and different capacitance values;
And a second switching unit that selects one of the plurality of capacitors and connects the other end of the selected capacitor to a feeding point of the receiving antenna.

A transmission circuit according to a second invention has a predetermined output impedance, power amplification means for amplifying and outputting a radio signal to be transmitted, and
A plurality of transmission filters each having a predetermined input / output impedance, each having a different pass band, and outputting a radio signal output from the power amplifying means by band-pass filtering;
Third switching means for selecting and outputting one radio signal among the radio signals output from the plurality of transmission filters;
In a transmission circuit having a predetermined antenna impedance and a transmission antenna for transmitting a radio signal output from the third switching means,
In response to the selection of the radio signal by the third switching means, the antenna impedance when the transmission antenna is viewed at the feed point in the pass band of the selected transmission filter is connected to the feed point of the transmission antenna. And adjusting means for adjusting the antenna impedance so that the antenna impedance is substantially the maximum and substantially coincides with the input / output impedance of the selected transmission filter and the output impedance of the power amplification means. .

In the transmission circuit, the adjusting means includes
A plurality of capacitors having one end grounded and different capacitance values;
And a fourth switching means for selecting one of the plurality of capacitors and connecting the other end of the selected capacitor to a feeding point of the transmitting antenna.

  A transmission / reception circuit according to a third aspect of the invention includes the reception circuit and the transmission circuit.

A wireless communication apparatus according to a fourth invention is
The transceiver circuit;
Demodulating means for demodulating a radio signal output from the low noise amplifying means of the receiving circuit into a baseband signal;
Modulation means for generating a radio signal by modulating a radio carrier according to a predetermined baseband signal and outputting the radio signal to the power amplifying means.

A transmission / reception circuit according to a fifth invention has a predetermined antenna impedance, and a transmission / reception antenna for transmitting / receiving a radio signal;
A reception filter having a predetermined input / output impedance and outputting a radio signal received by the transmission / reception antenna by band-pass filtering;
Low noise amplifying means having a predetermined input impedance and amplifying and outputting a radio signal output from the reception filter with low noise;
Power amplifying means having a predetermined output impedance and power-amplifying and outputting a radio signal to be transmitted;
In a transmission / reception circuit having a predetermined input / output impedance, and having a transmission filter that bandpass-filters a radio signal output from the power amplification means and outputs it to the transmission / reception antenna,
An impedance set to substantially match the output impedance of the power amplification means, and the transmission / reception antenna is viewed through the transmission filter at a connection point between the power amplification means and the transmission filter. When the impedance is the transmission antenna impedance,
Impedance set so as to substantially match the input impedance of the low noise amplifying means, via a phase shift means and the receiving filter at a connection point between the receiving filter and the low noise amplifying means. When the impedance when looking at the transmission / reception antenna is the reception antenna impedance,
Phase shift means is provided for shifting the radio signal output from the reception filter so that the transmission antenna impedance substantially matches the reception antenna impedance.

In the transmission / reception circuit, the reception filter includes a first reception filter unit having a pass band of a first reception frequency band, and a second reception frequency band different from the first reception frequency band. A reception filter unit,
The transmission filter includes a first transmission filter unit having a pass band of a first transmission frequency band, and a second transmission filter unit having a second transmission frequency band different from the first transmission frequency band. Prepared,
A radio signal provided between the transmission / reception antenna and the phase shifting means and the power amplification means, and is output from the transmission / reception antenna when the first reception frequency band and the first transmission frequency band are selected. Is output to the phase shift means via the first reception filter section, and a radio signal output from the power amplification means is output to the transmission / reception antenna via the first transmission filter section. When selecting the second reception frequency band and the second transmission frequency band, the radio signal output from the transmission / reception antenna is output to the phase shift means via the second reception filter unit, and The apparatus further comprises fifth switching means for outputting the radio signal output from the power amplifying means to the transmitting / receiving antenna via the second transmission filter section. To.

A transmission / reception circuit according to a sixth invention has a predetermined antenna impedance, and a transmission / reception antenna for transmitting / receiving a radio signal;
Low noise amplification means having a predetermined input impedance, and amplifying and outputting a radio signal output from the transmission / reception antenna with low noise;
Power amplifying means having a predetermined output impedance, power amplifying a radio signal to be transmitted, and outputting the amplified signal to the transmission / reception antenna;
Inserted between the transmitting / receiving antenna and the low noise amplifying means and the power amplifying means, and when receiving a radio signal, outputs a radio signal from the transmitting / receiving antenna to the low noise amplifying means, while transmitting a radio signal A transmission / reception circuit comprising a sixth switching means for switching to output a radio signal from the power amplification means to the transmission / reception antenna;
The impedance is set so as to substantially match the output impedance of the power amplifying means, and is connected via the sixth switching means at a connection point between the power amplifying means and the sixth switching means. The impedance when looking at the transmission / reception antenna is the transmission antenna impedance,
Impedance set to substantially match the input impedance of the low noise amplifying means, and the phase shifting means and the sixth at the connection point between the sixth switching means and the low noise amplifying means. When the impedance when the transmission / reception antenna is viewed through the switching means is the reception antenna impedance,
Phase shift means for shifting the radio signal output from the sixth switching means is provided so that the transmission antenna impedance substantially matches the reception antenna impedance.

A wireless communication apparatus according to a seventh aspect of the invention includes the transmission / reception circuit,
Demodulation means for demodulating the radio signal output from the low noise amplification means into a baseband signal;
Modulation means for generating a radio signal by modulating a radio carrier according to a predetermined baseband signal and outputting the radio signal to the power amplifying means.

  Further, in the receiving circuit, the antenna impedance of the receiving antenna is set to be higher than 50Ω.

  Furthermore, in the transmission circuit, the antenna impedance of the transmission antenna is set to be lower than 50Ω.

In the transceiver circuit, the antenna impedance of the receiving antenna is set to be higher than 50Ω,
The antenna impedance of the transmission antenna is set to be lower than 50Ω.

Furthermore, in the wireless communication device, the antenna impedance of the receiving antenna is set to be higher than 50Ω,
The antenna impedance of the transmission antenna is set to be lower than 50Ω.

  Therefore, according to the transmission / reception circuit and the wireless communication terminal apparatus using the same according to the present invention, the power supply point is connected to the feeding point of the receiving antenna, and in response to the selection of the radio signal by the first switching means, The antenna impedance when viewing the receiving antenna is substantially the minimum value in the pass band of the selected receiving filter, and is substantially equal to the input / output impedance of the selected receiving filter and the input impedance of the low noise amplifying means. Adjusting means for adjusting the antenna impedance so as to be consistent with each other. Alternatively, the antenna impedance when the transmission antenna is viewed at the feeding point is passed through the selected transmission filter in response to the selection of the radio signal by the third switching means connected to the feeding point of the transmission antenna. Adjusting means for adjusting the antenna impedance so as to be substantially the maximum in the band and substantially coincide with the input / output impedance of the selected transmission filter and the output impedance of the power amplification means is provided. Therefore, the output impedance inherently possessed by the power amplifying means and the input impedance inherently possessed by the low-noise amplifying means are not converted into impedances according to a specific impedance (for example, 50Ω), and are transmitted to the transmission / reception antenna. Therefore, it is possible to reduce the circuit scale as compared with the prior art without providing an impedance matching circuit, to greatly reduce circuit loss, and to use a transmission / reception circuit capable of operating in a wide band. A wireless communication device can be provided.

  Further, according to the transmission / reception circuit and the wireless communication terminal apparatus using the same according to the present invention, the impedance is set to substantially match the output impedance of the power amplification means, and the power amplification means and the power The impedance when the transmission / reception antenna is viewed through the transmission filter at the connection point with the transmission filter is set as the transmission antenna impedance, and is set to substantially match the input impedance of the low noise amplification means. When the impedance when the transmission / reception antenna is viewed through the phase shift means and the reception filter at the connection point between the reception filter and the low noise amplification means is the reception antenna impedance, The transmit antenna impedance becomes the receive antenna impedance. As qualitatively consistent comprises Sosuru phase it is shifting means shifting the radio signal output from the receiving filter. Alternatively, the impedance is set so as to substantially match the output impedance of the power amplifying means, and the sixth switching means is connected at a connection point between the power amplifying means and the sixth switching means. The impedance when the transmission / reception antenna is viewed via the transmission antenna impedance is an impedance set so as to substantially match the input impedance of the low-noise amplification means, and the sixth switching means and the above-described impedance When the impedance when the transmission / reception antenna is viewed through the phase shift means and the sixth switching means at the connection point with the low noise amplification means is the reception antenna impedance, the transmission antenna impedance is the reception frequency. The output from the sixth switching means so as to substantially match the antenna impedance. Comprising a transfer Sosuru phase shifting means a radio signal that. Therefore, the output impedance inherently possessed by the power amplifying means and the input impedance inherently possessed by the low-noise amplifying means are not converted into impedances according to a specific impedance (for example, 50Ω), and are transmitted to the transmission / reception antenna. Therefore, it is possible to reduce the circuit scale as compared with the prior art without providing an impedance matching circuit, to greatly reduce circuit loss, and to use a transmission / reception circuit capable of operating in a wide band. A wireless communication device can be provided.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each following embodiment, the same code | symbol is attached | subjected about the same component.

First embodiment.
FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus provided with a transmission / reception circuit according to the first embodiment of the present invention.

  In FIG. 1, a transmission baseband signal to be transmitted to a base station is input to a modulator 110 via an input terminal 112 and modulated using a predetermined digital modulation method. The signal is output and radiated to the transmission antenna 102 via the transmission input terminal 108, the transmission power amplifier 106, and the transmission filter 106, which is a band-pass filter, for example, which filters only the transmission radio signal. The transmission filter 106 and the power supply terminal of the transmission antenna 102 are preferably connected by a power supply line having a shortest electrical length and a predetermined characteristic impedance, or directly connected. The same applies to each embodiment described later.

  On the other hand, the reception radio signal received by the reception antenna 101 is demodulated through the reception filter 103, which is a band-pass filter, the reception low noise amplifier 105, and the reception output terminal 107, for example, which only band-pass-filters the reception radio signal. Is input to the device 109. The demodulator 109 demodulates the input received radio signal into a received baseband signal using a predetermined digital demodulation method, and then outputs it via the output terminal 111. The receiving filter 103 and the feeding terminal of the receiving antenna 101 are preferably connected by a feeding line having a shortest possible electrical length and a predetermined characteristic impedance, or directly connected. The same applies to each embodiment described later.

  In FIG. 1, a demodulator 109 and a modulator 110 are shown. On the other hand, although illustration of these is omitted in FIG. 4 and subsequent figures, the radio communication device may naturally include the demodulator 109 and the modulator 110.

  In the wireless communication apparatus of FIG. 1, since the reception low-noise amplifier 105 is generally intended to amplify a minute reception signal, the size of the input transistor 105A provided in the input stage becomes a relatively small value, and the parasitic For example, when the input transistor 105A is a bipolar transistor, the input impedance at its base (when the input transistor 105A is a field effect transistor, the input impedance at its gate) is usually reduced. Compared to 50Ω, which is the characteristic impedance (hereinafter referred to as normal characteristic impedance) of the antenna and the feeder line, it is 200Ω, for example. In the present embodiment, the antenna impedance of the receiving antenna 101 (hereinafter, the impedance when the antenna side is viewed at the feeding terminal (or feeding point) of the antenna is referred to as antenna impedance) and the characteristic impedance of the feeding line (receiving filter 103 and When the receiving antenna 101 is directly connected, the feed line is omitted.) And the input impedance and output impedance of the receiving filter 103 are higher than the normal characteristic impedance. It is preferable to set to match the impedance (for example, 200Ω). As a result, since no impedance matching circuit is required in the receiving circuit, the circuit configuration can be simplified as compared with the conventional example, whereby the circuit loss can be greatly reduced and a broadband receiving circuit can be configured.

  Further, since the transmission power amplifier 106 is generally intended to amplify the wireless power enough to reach the base station, the size of the output transistor 106A is increased and the parasitic capacitance component is also increased. It becomes a low value (for example, 10Ω). In this embodiment, the antenna impedance of the transmission antenna 102, the characteristic impedance of the feed line (when the transmission filter 104 and the transmission antenna 102 are directly connected, the feed line is omitted), and the input of the transmission filter 104 It is preferable to set the impedance and the output impedance so as to coincide with the output impedance (for example, 10Ω) of the transmission power amplifier 106, which is lower than the normal characteristic impedance. As a result, since no impedance matching circuit is required in the transmission circuit, the circuit configuration can be simplified as compared with the conventional example, whereby the circuit loss can be greatly reduced and a broadband receiving circuit can be configured.

  FIG. 2 is a diagram showing a current distribution and a voltage distribution with respect to the longitudinal direction of the antenna, showing an operation example of the half-wave dipole antenna 251 of the wireless communication apparatus of FIG.

  In the half-wave dipole antenna 251 of FIG. 2, a pair of feed terminals 241 and 242 are provided at the center of a pair of antenna elements. In this embodiment, it is considered that the terminal 252 or 253 is used instead of the power supply terminal 242. In the half-wave dipole antenna 251 of FIG. 2, the voltage and current of the high frequency signal are distributed as indicated by 255 and 254, respectively. Therefore, the high impedance terminal 252 where the voltage is higher than the current has a high voltage of the high frequency signal. The characteristic that the current of the signal is small, that is, the impedance becomes high can be obtained. Further, the low impedance terminal 253 in which the voltage is lower than the current can obtain characteristics such that the voltage is small and the current is large, that is, the impedance is low.

  3A is a schematic plan view showing a configuration example of the half-wavelength dipole antenna 351, and FIG. 3B is a schematic plan view showing a configuration example of the half-wavelength folded dipole antenna 350.

  In FIG. 3A, the antenna impedance of a pair of feeding terminals 352 of a half-wave dipole antenna 351 composed of a pair of antenna elements 351a and 351b is about 75Ω. On the other hand, in FIG. 3B, the antenna impedance of the pair of feeding terminals 353 of the half-wavelength folded dipole antenna 350 is about 300Ω. That is, the half-wavelength folded dipole antenna 350 has an antenna impedance four times that of the half-wavelength dipole antenna 351 (see, for example, Non-Patent Document 1).

  If the high impedance terminal 252 of the half-wavelength dipole antenna 251 in FIG. 2 or the half-wavelength folded dipole antenna 350 in FIG. 3 is used, the reception antenna 101 that matches the input impedance of the reception low-noise amplifier 105 can be used. Therefore, it is possible to obtain a good reception characteristic without providing an impedance matching circuit at the input stage of the reception low noise amplifier 105, and an impedance matching circuit is unnecessary, so that it is not affected by the frequency dependence of the impedance matching circuit. It is possible to realize a proper reception characteristic. Further, the input / output impedance of the reception filter 103 is set to an impedance value substantially the same as the input impedance of the reception low noise amplifier 105, so that reception is performed between the reception antenna 101 and the reception low noise amplifier 105. Even if the filter 103 is inserted, it is possible to obtain good reception characteristics, and an impedance matching circuit is unnecessary, so that it is possible to realize a wide band reception characteristic without being affected by the frequency dependence of the impedance matching circuit.

  Further, if the low impedance terminal 253 of the half-wave dipole antenna 251 in FIG. 2 or the half-wave dipole antenna 351 in FIG. 3 is used, the transmission antenna 102 in which the antenna impedance is matched with the output impedance of the transmission power amplifier 106 is used. Therefore, even without providing an impedance matching circuit at the output stage of the transmission power amplifier 106, it is possible to obtain good transmission characteristics, and an impedance matching circuit is unnecessary, so that it is affected by the frequency dependence of the impedance matching circuit. Therefore, it is possible to realize a wide band transmission characteristic. Further, by configuring the input / output impedance of the transmission filter 104 to be substantially the same impedance value as the output impedance of the transmission power amplifier 106, the transmission filter 104 is provided between the transmission antenna 102 and the transmission power amplifier 106. Even if is inserted, good transmission characteristics can be obtained, and since an impedance matching circuit is not required, wide band transmission characteristics can be realized without being affected by the frequency dependence of the impedance matching circuit.

Second embodiment.
FIG. 4 is a block diagram showing a configuration of a wireless communication apparatus including a transmission / reception circuit according to the second embodiment of the present invention.

  Compared with the transmission circuit according to the first embodiment of FIG. 1, the transmission circuit according to the second embodiment is arranged between the transmission antenna 102 and the transmission power amplifier 106 so as to correspond to each transmission band. Three transmission filters 404a, 404b, and 404c having different band pass bands, and a pair of switch circuits 410 and 412 that selectively connect and switch these three transmission filters 404a, 404b, and 404c in parallel. It is characterized by having. Here, the switch circuit 410 includes a switch SW11, and the switch circuit 412 includes a switch SW12. In addition, the receiving circuit according to the second embodiment corresponds to each receiving band between the receiving antenna 101 and the receiving low noise amplifier 105 as compared with the receiving circuit according to the first embodiment of FIG. Thus, three reception filters 403a, 403b, and 403c having mutually different band pass bands and a pair of switch circuits that are selectively and interlocked by interposing these three reception filters 403a, 403b, and 403c in parallel. 409, 411. Here, the switch circuit 409 includes a switch SW1, and the switch circuit 411 includes a switch SW2.

  In the transmission circuit according to the second embodiment configured as described above, when the switches SW11 and SW12 are switched to the contact a side in conjunction with each other, the transmission radio signal input via the transmission signal input terminal 108 is The power is output and radiated to the transmission antenna 102 via the transmission power amplifier 106, the contact a side of the switch SW12, the transmission filter 404a, and the contact a side of the switch SW11. When the switches SW11 and SW12 are switched to the contact b side in conjunction with each other, the transmission radio signal input through the transmission signal input terminal 108 is transmitted to the transmission power amplifier 106, the contact b side of the switch SW12, and the transmission filter. The light is output and radiated to the transmitting antenna 102 via 404b and the contact b side of the switch SW11. Further, when the switches SW11 and SW12 are switched to the contact c side in conjunction with each other, the transmission radio signal input via the transmission signal input terminal 108 is transmitted to the transmission power amplifier 106, the contact c side of the switch SW12, and the transmission filter. The light is output and radiated to the transmitting antenna 102 via 404c and the contact c side of the switch SW11.

  In the receiving circuit according to the second embodiment configured as described above, when the switches SW1 and SW2 are switched to the contact a side in conjunction with each other, the received radio signal received by the receiving antenna 101 is the switch SW1. Output from the contact a side, the reception filter 403a, the contact a side of the switch SW2, the reception low noise amplifier 105, and the reception output terminal 107. When the switches SW1 and SW2 are switched to the contact b side in conjunction with each other, the reception radio signal received by the receiving antenna 101 is transmitted to the contact b side of the switch SW1, the reception filter 403b, and the contact b side of the switch SW2. The signal is output via the reception low noise amplifier 105 and the reception output terminal 107. Further, when the switches SW1 and SW2 are switched to the contact c side in conjunction with each other, the reception radio signal received by the receiving antenna 101 is transmitted to the contact c side of the switch SW1, the reception filter 403c, and the contact c side of the switch SW2. The signal is output via the reception low noise amplifier 105 and the reception output terminal 107.

  In the receiving circuit according to the second embodiment configured as described above, the receiving antenna 101 having an antenna impedance substantially matching the input impedance of the receiving low-noise amplifier 405 is used as in the first embodiment. The input / output impedances of the reception filters 403a, 403b, and 403c are set to substantially match the antenna impedance. Therefore, as in the first embodiment, good reception characteristics can be obtained, and since no impedance matching circuit is required, it is possible to realize wideband reception characteristics without being affected by the frequency dependence of the impedance matching circuit. .

  In the transmission circuit according to the second embodiment, similarly to the first embodiment, the reception antenna 102 having an antenna impedance substantially matching the output impedance of the transmission power amplifier 106 is used, and each transmission filter 404a is used. , 404b, 404c are set so as to substantially match the antenna impedance. Therefore, as in the first embodiment, good transmission characteristics can be obtained and an impedance matching circuit is unnecessary, so that it is possible to realize a wide band transmission characteristic without being affected by the frequency dependence of the impedance matching circuit. .

  In the first and second embodiments described above, the input matching circuit of the reception low noise amplifier 105 and the output matching circuit of the transmission power amplifier 106 are not used, but depending on the impedance of the reception antenna 101 or the transmission antenna 102. Thus, even if a simple impedance matching circuit is provided without departing from the gist of the present invention, the same effect can be obtained. Further, depending on the frequency characteristic of the characteristic impedance of the reception antenna 101 or the transmission antenna 102, an input matching circuit of the reception low noise amplifier 105 or an output matching circuit of the transmission power amplifier 106 depending on the frequency may be simply provided.

  In the second embodiment described above, the three reception filters 404a, 404b, and 404c are provided. However, the present invention is not limited to this, and two or more reception filters may be provided. In the second embodiment described above, the three transmission filters 403a, 403b, and 403c are provided. However, the present invention is not limited to this, and two or four or more transmission filters may be provided.

Modified example of the second embodiment.
FIG. 5 is a block diagram showing a configuration of a wireless communication apparatus provided with a transmission / reception circuit according to a modification of the second embodiment of the present invention. 6A is a graph showing the corrected transmission antenna impedance Zat with respect to the transmission frequency, showing an operation example of the transmission circuit of the wireless communication apparatus of FIG. 5, and FIG. 6B is the wireless communication apparatus of FIG. It is a graph which shows the receiving antenna impedance Zar after correction | amendment with respect to the receiving frequency which shows the operation example of this receiver circuit.

  The receiving circuit according to the modified example of the second embodiment is 3 for correcting the reception frequency characteristic of the antenna impedance instead of the switch circuit 410 as compared with the receiving circuit according to the second embodiment of FIG. One capacitor C11, C12, C13 (capacitance value C11 <C12 <C13; the capacitance value C11 may be substantially zero) and one of these three capacitors C11, C12, C13. A switch circuit 410A further including a switch SW13 for selectively switching is provided. In addition, the transmission circuit according to the modification of the second embodiment corrects the transmission frequency characteristic of the antenna impedance instead of the switch circuit 409 as compared with the transmission circuit according to the second embodiment of FIG. Capacitor C1, C2, C3 (C1 <C2 <C3; capacitance value C1 may be substantially zero)) and one of these three capacitors C1, C2, C3 And a switch circuit 409A further including a switch SW3 for selectively switching between. Hereinafter, the difference will be described in detail. As shown in FIG. 6A, the band of the transmission frequency or the reception frequency becomes higher in the order of band 3, band 2, and band 1, and the reception filter 403a is a reception filter for band 1, and the reception filter 403b is a reception filter for band 2, and reception filter 403c is a reception filter for band 3. The transmission filter 404a is a transmission filter for band 1, the transmission filter 404b is a transmission filter for band 2, and the transmission filter 404c is a transmission filter for band 3.

  In the transmission circuit of FIG. 5, when band 1 is used as a transmission frequency band, the switches SW11, SW12, and SW13 are respectively switched to the contact a side. At this time, when the capacitor C11 is connected to the transmission antenna 102 and the transmission antenna 102 is viewed at the common terminal of the switch SW11, the transmission antenna impedance Zat corrected by the capacitor C11 is as indicated by 451 in FIG. In addition, the capacitance value of the capacitor C11 is set to be the minimum value at the approximate center frequency of the band 1. At this time, the minimum value of the transmission antenna impedance Zat can be substantially matched with the input / output impedance of the transmission filter 404a and the output impedance of the transmission power amplifier 106, and the transmission radio signal is transmitted to the transmission antenna in the impedance matching state. 102 can be transmitted and emitted.

  When band 2 is used as the transmission frequency band, the switches SW11, SW12, and SW13 are switched to the contact b side. At this time, when the capacitor C12 is connected to the transmission antenna 102 and the transmission antenna 102 is viewed at the common terminal of the switch SW11, the transmission antenna impedance Zat corrected by the capacitor C12 is as indicated by 452 in FIG. In addition, the capacitance value of the capacitor C12 is set to be the minimum value at the approximate center frequency of the band 2. At this time, the minimum value of the transmission antenna impedance Zat can be substantially matched with the input / output impedance of the transmission filter 404a and the output impedance of the transmission power amplifier 106, and the transmission radio signal is transmitted to the transmission antenna in the impedance matching state. 102 can be transmitted and emitted.

  Further, when band 3 is used as a transmission frequency band, switches SW11, SW12, and SW13 are switched to the contact c side. At this time, the transmission antenna impedance Zat corrected by the capacitor C13 when the capacitor C13 is connected to the transmission antenna 102 and the transmission antenna 102 is viewed at the common terminal of the switch SW11 is as indicated by 453 in FIG. In addition, the capacitance value of the capacitor C13 is set so as to be the minimum value at the approximate center frequency of the band 3. At this time, the minimum value of the transmission antenna impedance Zat can be substantially matched with the input / output impedance of the transmission filter 404a and the output impedance of the transmission power amplifier 106, and the transmission radio signal is transmitted to the transmission antenna in the impedance matching state. 102 can be transmitted and emitted.

  As described above, according to the band of the transmission frequency, the transmission antenna impedance Zat when the transmission antenna 102 is viewed from the output end of the wireless transmitter is set to a relatively small value of the transmission power amplifier 106 (as described above, The output impedance can be set to a value smaller than the characteristic impedance of the antenna and the feed line (for example, 50Ω, for example, 10Ω), thereby transmitting the transmission radio signal to the transmission antenna 102 in an impedance matching state. It can be transmitted and radiated, and transmission loss can be greatly reduced with a very simple configuration.

  In the receiving circuit of FIG. 5, when the band 1 is used as the reception frequency band, the switches SW1, SW2, and SW3 are switched to the contact a side. At this time, when the capacitor C1 is connected to the receiving antenna 101 and the receiving antenna 101 is viewed at the common terminal of the switch SW1, the receiving antenna impedance Zar corrected by the capacitor C1 is as indicated by 461 in FIG. 6B. In addition, the capacitance value of the capacitor C1 is set so as to be the maximum value at the approximate center frequency of the band 1. At this time, the maximum value of the reception antenna impedance Zar can be substantially matched with the input / output impedance of the reception filter 403a and the input impedance of the reception low noise amplifier 105, and the reception radio wave received by the reception antenna 101 is received. The signal can be transmitted to the reception low noise amplifier 105 in an impedance matching state and received.

  When band 2 is used as the reception frequency band, the switches SW1, SW2, and SW3 are switched to the contact b side. At this time, when the capacitor C2 is connected to the reception antenna 101 and the reception antenna 101 is viewed at the common terminal of the switch SW1, the reception antenna impedance Zar corrected by the capacitor C2 is as indicated by 452 in FIG. Further, the capacitance value of the capacitor C2 is set so as to be the minimum value at the approximate center frequency of the band 2. At this time, the minimum value of the reception antenna impedance Zar can be substantially matched with the input / output impedance of the reception filter 403b and the input impedance of the reception low-noise amplifier 105, and the reception radio wave received by the reception antenna 101 is received. The signal can be transmitted to the reception low noise amplifier 105 in an impedance matching state and received.

  Further, when band 3 is used as the reception frequency band, the switches SW1, SW2 and SW3 are respectively switched to the contact c side. At this time, when the capacitor C3 is connected to the receiving antenna 101 and the receiving antenna 101 is viewed at the common terminal of the switch SW1, the receiving antenna impedance Zar corrected by the capacitor C3 is as indicated by 453 in FIG. Further, the capacitance value of the capacitor C3 is set so as to be the minimum value at the approximate center frequency of the band 3. At this time, the minimum value of the reception antenna impedance Zar can be substantially matched with the input / output impedance of the reception filter 403 c and the input impedance of the reception low noise amplifier 105, and the reception radio wave received by the reception antenna 101 is received. The signal can be transmitted to the reception low noise amplifier 105 in an impedance matching state and received.

  As described above, the reception antenna impedance Zar when the reception antenna 101 is viewed from the output end of the wireless receiver according to the band of the reception frequency is set to a relatively large value (as described above) of the reception low noise amplifier 105. , Which is larger than the characteristic impedance of the antenna and the feed line (for example, 50Ω), for example, 200Ω), so that the received radio signal received by the receiving antenna 101 can be changed. Transmission can be received up to the reception low noise amplifier 105 in the impedance matching state, and transmission loss can be greatly reduced with an extremely simple configuration.

Third embodiment.
FIG. 7 is a block diagram showing a configuration of a wireless communication apparatus including a transmission / reception circuit according to the third embodiment of the present invention. FIG. 8 shows frequency characteristics of antenna impedance showing an operation example of the wireless communication apparatus of FIG. It is a graph to show. FIG. 9 is a block diagram showing a detailed configuration and an operation example of the antenna sharing filter 522 of FIG.

  7 is a so-called duplexer, and includes a transmission filter 522a and a reception filter 522b as shown in FIG. Here, the output-side connection terminal 522 at of the reception filter 522 a is connected to the input terminal of the reception low-noise amplifier 105. The connection terminal 522bt on the input side of the transmission filter 522b is connected to the output terminal of the transmission power amplifier 106. In FIG. 7, the reception radio signal received by the transmission / reception antenna 521 is input to the reception low noise amplifier 105 via the reception filter 522 a of the antenna shared filter 522, amplified by low noise, and then received via the reception signal output terminal 107. Is output. On the other hand, the transmission radio signal input to the transmission signal input terminal 108 is output and radiated to the transmission / reception antenna 521 via the transmission power amplifier 106 and the transmission filter 522b of the antenna shared filter 522.

  FIG. 8 shows a frequency characteristic of a general antenna impedance. As shown in FIG. 8, in consideration of the frequency characteristics of the antenna impedance, a band having a lower antenna impedance is assigned to a transmission frequency, and a band having a higher antenna impedance is assigned to a reception frequency. If the transmission / reception frequency is assigned in this way, the output impedance of the transmission power amplifier 105 is set to a relatively lower antenna impedance value of the transmission / reception antenna 521 (as described above, the characteristic impedance of the antenna and the feed line (for example, 50Ω)). Is set to match the input impedance of the reception low noise amplifier 106, while the antenna impedance value of the transmission / reception antenna 521 is relatively higher (as described above, the antenna and the feed line). The characteristic impedance (for example, 50Ω) is preferably set so as to match. Here, the reception side filter of the antenna shared filter 522 is configured with the input impedance of the reception low noise amplifier 505 as the characteristic impedance, and the transmission side filter of the antenna shared filter 522 is configured with the output impedance of the transmission power amplifier 506 as the characteristic impedance. Thus, as in the first embodiment, good reception characteristics and transmission characteristics can be obtained, and since no impedance matching circuit is required, the wideband reception characteristics and transmission are not affected by the frequency dependence of the impedance matching circuit. The characteristics can be realized.

  9, as described above, the input / output impedance of the transmission filter 522a is set to a relatively low impedance value that matches the output impedance value of the transmission power amplifier 105 (as described above, the antenna and the power feed). The transmission filter 522a is configured to have a value smaller than the characteristic impedance of the line (for example, 50Ω, for example, 10Ω), and the input / output impedance of the reception filter 522b is set as a reception low noise amplifier. The impedance is set to a relatively high impedance value that matches the input impedance of 106 (as described above, a value that is larger than the characteristic impedance of the antenna and the feed line (for example, 50Ω), for example, 200Ω). A reception filter 522b is configured. Thereby, since the characteristic impedances are different from each other, leakage of the transmission radio signal to the reception filter 522b can be reduced, and leakage of the reception radio signal to the transmission filter 522a can also be reduced. That is, the isolation between transmission and reception can be improved.

Modified example of the third embodiment.
FIG. 10 is a block diagram showing a configuration of a wireless communication apparatus including a transmission / reception circuit according to a modification of the third embodiment of the present invention, and FIG. 11 is a transmission antenna impedance Zat in the operation example of the wireless communication apparatus of FIG. 4 is a Smith chart showing reception antenna impedance Zar. The wireless communication apparatus according to the modification of the third embodiment is different from the wireless communication apparatus according to the third embodiment of FIG. 7 in that the connection terminal 522at of the reception filter 522a and the input terminal of the reception low noise amplifier 105 The phase shifter 524 is inserted between the two.

  In the wireless communication apparatus of FIG. 10, the antenna impedance of the transmission / reception antenna 521 is set to a value lower than the relatively low output impedance value of the transmission power amplifier 105 (as described above, the characteristic impedance of the antenna and the feed line (for example, 50Ω)). 11, for example, 10Ω.) A phase shifter 524 for rotating the received radio signal only in the receiving circuit to phase-rotate 527 as shown in the Smith chart of FIG. 11 is provided. The same transmission / reception antenna 521 is converted by converting the impedance on the side into a higher impedance value (as described above, a value larger than the characteristic impedance (for example, 50Ω) of the antenna and the feed line, for example, 200Ω). The transmission / reception impedance difference can be realized using. Here, the phase shifter 524 can be constituted by a transmission line having a predetermined electrical length, for example.

  FIG. 11 is an operation example of the wireless communication apparatus of FIG. 10, and the antenna impedance when the transmission / reception antenna 521 is viewed at the connection point 525 between the output terminal of the transmission power amplifier 106 and the connection terminal of the transmission filter 522 b. Is Zat, and the antenna impedance when the transmission / reception antenna 521 is viewed at the connection point 526 between the input terminal of the reception low-noise amplifier 105 and the connection terminal of the reception filter 522a is Zar. The Smith chart of FIG. 11 shows the transmission antenna impedance Zat and the reception antenna impedance Zar when swept in a predetermined frequency range, and the transmission antenna impedance Zat is phase-rotated 527 to the reception antenna impedance Zar by the phase shifter 524. Can do.

  As described above, according to the modification of the third embodiment, by inserting the phase shifter 524 for phase rotation before the reception low noise amplifier 105 of the reception circuit, the impedance value can be further increased. By converting the impedance value to a low value, good reception characteristics and transmission characteristics can be obtained as in the first embodiment, and since no impedance matching circuit is required, the impedance matching circuit is affected by the frequency dependence. In addition, wideband reception characteristics and transmission characteristics can be realized.

Fourth embodiment.
FIG. 12 is a block diagram showing a configuration of a wireless communication apparatus provided with a transmission / reception circuit according to the fourth embodiment of the present invention. The wireless communication apparatus according to the fourth embodiment includes a transmission / reception changeover switch SW31 instead of the antenna shared filter 522, as compared with the wireless communication apparatus according to the modification of the third embodiment of FIG. It is a feature. Here, the switch SW31 is switched to the contact b side during transmission, and is switched to the contact a side during reception. By configuring as described above, since the phase shifter 524 is provided, good reception characteristics and transmission characteristics can be obtained as in the modification of the third embodiment, and an impedance matching circuit is unnecessary. Broadband reception characteristics and transmission characteristics can be realized without being affected by the frequency dependence of the impedance matching circuit.

  In the above embodiment, the phase shifter 524 having the same function and effect as in FIG. 10 is inserted between the contact a side of the switch SW31 and the input terminal of the reception low noise amplifier 105. Not limited to this, the phase shifter 524 may not be inserted.

Fifth embodiment.
FIG. 13 is a block diagram illustrating a configuration of a wireless communication apparatus including a transmission / reception circuit according to the fifth embodiment of the present invention. Compared with the wireless communication apparatus according to the fourth embodiment of FIG. 12, the wireless communication apparatus according to the fifth embodiment replaces the transmission / reception changeover switch SW31 with a frequency band changeover switch SW21 and two antenna sharing filters. 922a and 922b, a reception frequency band changeover switch SW22, and a transmission frequency band changeover switch SW23. Here, the antenna sharing filter 922a is configured to include a reception filter 922aa and a transmission filter 922ab, and the antenna sharing filter 922b is configured to include a reception filter 922ba and a transmission filter 922bb. Note that the common terminal of the switch SW22 is connected to the input terminal of the reception low noise amplifier 105 via the phase shifter 524 having the same effect as that of FIG.

  In the wireless communication apparatus of FIG. 13, when transmission / reception is performed in a certain first band, each switch SW21, SW22, SW23 is switched to the contact a side. At this time, the radio reception signal received by the transmission / reception antenna 521 is received via the contact a side of the switch SW21, the reception filter 922aa of the antenna shared filter 922a, the contact a side of the switch SW22, and the phase shifter 524. After being input to the low noise amplifier 105 and amplified with low noise, it is output via the reception signal output terminal 107. On the other hand, the wireless transmission signal input via the transmission signal input terminal 108 is transmitted to the transmission / reception antenna 521 via the contact a side of the switch SW23, the transmission filter 922ab of the antenna shared filter 922a, and the contact a side of the switch SW21. Output and radiate.

  When transmitting / receiving in another second band, each switch SW21, SW22, SW23 is switched to the contact b side. At this time, the radio reception signal received by the transmission / reception antenna 521 is received via the contact b side of the switch SW21, the reception filter 922ba of the antenna shared filter 922b, the contact b side of the switch SW22, and the phase shifter 524. After being input to the low noise amplifier 105 and amplified with low noise, it is output via the reception signal output terminal 107. On the other hand, the wireless transmission signal input via the transmission signal input terminal 108 is transmitted to the transmission / reception antenna 521 via the contact b side of the switch SW23, the transmission filter 922bb of the antenna sharing filter 922b, and the contact b side of the switch SW21. Output and radiate.

  By configuring as described above, since the phase shifter 524 is provided, good reception characteristics and transmission characteristics can be obtained as in the modification of the third embodiment, and an impedance matching circuit is unnecessary. Broadband reception characteristics and transmission characteristics can be realized without being affected by the frequency dependence of the impedance matching circuit.

  In the above fifth embodiment, the phase shifter 524 is inserted. However, the present invention is not limited to this, and the phase shifter 524 may not be inserted.

Modified example.
In the above embodiment, the input impedance matching circuit of the reception low noise amplifier 105 and the output impedance matching circuit of the transmission power amplifier 106 are not used, but the antenna impedance of the reception antenna 101, the transmission antenna 102, or the transmission / reception antenna 521 or Depending on the frequency characteristics, a simple impedance matching circuit may be provided without departing from the spirit of the present invention.

  As described above in detail, according to the transmission / reception circuit and the wireless communication terminal device using the same according to the present invention, the output impedance inherently possessed by the power amplifying means and the input inherently possessed by the low-noise amplifying means. Since the impedance can be guided to the transmission / reception antenna without impedance conversion in accordance with a specific impedance (for example, 50Ω), the circuit scale can be reduced as compared with the conventional example without providing an impedance matching circuit. In addition, it is possible to provide a transmission / reception circuit that can significantly reduce circuit loss and operate in a wide band, and a wireless communication device using the transmission / reception circuit.

It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the 1st Embodiment of this invention. It is a figure which shows the current distribution and voltage distribution with respect to the longitudinal direction of the antenna which shows the operation example of the half-wavelength dipole antenna 251 of the radio | wireless communication apparatus of FIG. (A) is a schematic plan view showing a configuration example of a half-wavelength dipole antenna 351, and (b) is a schematic plan view showing a configuration example of a half-wavelength folded dipole antenna 350. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the modification of the 2nd Embodiment of this invention. (A) is a graph showing the corrected transmission antenna impedance Zat with respect to the transmission frequency showing an operation example of the transmission circuit of the wireless communication device of FIG. 5, and (b) is an operation example of the reception circuit of the wireless communication device of FIG. It is a graph which shows the receiving antenna impedance Zar after correction | amendment with respect to the receiving frequency which shows. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the 3rd Embodiment of this invention. It is a graph which shows the frequency characteristic of the antenna impedance which shows the operation example of the radio | wireless communication apparatus of FIG. FIG. 8 is a block diagram illustrating a detailed configuration and an operation example of the antenna sharing filter 522 in FIG. 7. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the modification of the 3rd Embodiment of this invention. 11 is a Smith chart showing a transmission antenna impedance Zat and a reception antenna impedance Zar in the operation example of the wireless communication apparatus in FIG. 10. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus provided with the transmission / reception circuit which concerns on the 5th Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus which concerns on a prior art example.

Explanation of symbols

101 ... receiving antenna,
102: Transmitting antenna,
103, 403a, 403b, 403c ... reception filter,
104, 404a, 404b, 404c ... transmission filter,
105... Reception low noise amplifier,
105A ... input transistor,
106: Transmit power amplifier,
106A: Output transistor,
107: Received signal output terminal,
108: Transmission signal input terminal,
109 ... demodulator,
110: modulator,
111 ... output terminal,
112 ... input terminal,
241,242 ... feed terminals,
251, 351 ... half-wave dipole antenna,
350: Half-wavelength folded dipole antenna,
409, 409A, 410, 410A, 411, 412 ... switch circuit,
521: Transmit / receive antenna,
522 ... Antenna common filter,
522a ... transmission filter,
522b ... reception filter,
522at, 522bt ... connection terminal,
524 ... Phase shifter,
525, 526 ... connection point,
922a, 922b ... antenna shared filter,
922aa, 922ba... Reception filter,
922ab, 922bb ... transmission filter,
C1, C2, C3, C11, C12, C13 ... impedance matching capacitors,
SW1, SW2, SW3, SW11, SW12, SW13, SW21, SW22, SW23, SW31... Switch.

Claims (14)

A receiving antenna having a predetermined antenna impedance and receiving a radio signal;
A plurality of reception filters each having a predetermined input / output impedance, each having a different pass band, and outputting a radio signal received by the receiving antenna through band pass filtering;
First switching means for selecting and outputting one of the radio signals output from the plurality of reception filters;
In a receiving circuit having a predetermined input impedance, and a low noise amplifying means for amplifying and outputting a radio signal output from the switching means by low noise,
The antenna impedance when the receiving antenna is viewed at the feeding point is connected to the feeding point of the receiving antenna according to the selection of the radio signal by the first switching means in the pass band of the selected receiving filter. And adjusting means for adjusting the antenna impedance so that it is substantially the minimum value and substantially matches the input / output impedance of the selected receiving filter and the input impedance of the low noise amplifying means. Receiving circuit. The adjusting means is
A plurality of capacitors having one end grounded and different capacitance values;
Second switching means for selecting one of the plurality of capacitors and connecting the other end of the selected capacitor to the feeding point of the receiving antenna; The receiving circuit according to claim 1. Power amplifying means having a predetermined output impedance and power-amplifying and outputting a radio signal to be transmitted;
A plurality of transmission filters each having a predetermined input / output impedance, each having a different pass band, and outputting a radio signal output from the power amplifying means by band-pass filtering;
Third switching means for selecting and outputting one radio signal among the radio signals output from the plurality of transmission filters;
In a transmission circuit having a predetermined antenna impedance and a transmission antenna for transmitting a radio signal output from the third switching means,
In response to the selection of the radio signal by the third switching means, the antenna impedance when the transmission antenna is viewed at the feed point in the pass band of the selected transmission filter is connected to the feed point of the transmission antenna. And adjusting means for adjusting the antenna impedance so that the antenna impedance is substantially the maximum and substantially coincides with the input / output impedance of the selected transmission filter and the output impedance of the power amplification means. Transmitter circuit. The adjusting means is
A plurality of capacitors having one end grounded and different capacitance values;
4. A fourth switching means for selecting one of the plurality of capacitors and connecting the other end of the selected capacitor to a feeding point of the transmitting antenna. Transmitter circuit. The receiving circuit according to claim 1 or 2,
A transmission / reception circuit comprising the transmission circuit according to claim 3. A transceiver circuit according to claim 5;
Demodulating means for demodulating a radio signal output from the low noise amplifying means of the receiving circuit into a baseband signal;
A radio communication apparatus comprising: modulation means for generating a radio signal by modulating a radio carrier according to a predetermined baseband signal and outputting the radio signal to the power amplifying means. A transmitting and receiving antenna having a predetermined antenna impedance and transmitting and receiving a radio signal;
A reception filter having a predetermined input / output impedance and outputting a radio signal received by the transmission / reception antenna by band-pass filtering;
Low noise amplifying means having a predetermined input impedance and amplifying and outputting a radio signal output from the reception filter with low noise;
Power amplifying means having a predetermined output impedance and power-amplifying and outputting a radio signal to be transmitted;
In a transmission / reception circuit having a predetermined input / output impedance, and having a transmission filter that bandpass-filters a radio signal output from the power amplification means and outputs it to the transmission / reception antenna,
An impedance set to substantially match the output impedance of the power amplification means, and the transmission / reception antenna is viewed through the transmission filter at a connection point between the power amplification means and the transmission filter. When the impedance is the transmission antenna impedance,
Impedance set so as to substantially match the input impedance of the low noise amplifying means, via a phase shift means and the receiving filter at a connection point between the receiving filter and the low noise amplifying means. When the impedance when looking at the transmission / reception antenna is the reception antenna impedance,
A transmission / reception circuit comprising phase shifting means for phase shifting a radio signal output from the reception filter so that the transmission antenna impedance substantially matches the reception antenna impedance. The reception filter includes a first reception filter unit having a pass band of a first reception frequency band, and a second reception filter unit having a second reception frequency band different from the first reception frequency band. Prepared,
The transmission filter includes a first transmission filter unit having a pass band of a first transmission frequency band, and a second transmission filter unit having a second transmission frequency band different from the first transmission frequency band. Prepared,
A radio signal provided between the transmission / reception antenna and the phase shifting means and the power amplification means, and is output from the transmission / reception antenna when the first reception frequency band and the first transmission frequency band are selected. Is output to the phase shift means via the first reception filter section, and a radio signal output from the power amplification means is output to the transmission / reception antenna via the first transmission filter section. When selecting the second reception frequency band and the second transmission frequency band, the radio signal output from the transmission / reception antenna is output to the phase shift means via the second reception filter unit, and The apparatus further comprises fifth switching means for outputting the radio signal output from the power amplifying means to the transmitting / receiving antenna via the second transmission filter section. Transmitting and receiving circuit according to claim 7. A transmitting and receiving antenna having a predetermined antenna impedance and transmitting and receiving a radio signal;
Low noise amplification means having a predetermined input impedance, and amplifying and outputting a radio signal output from the transmission / reception antenna with low noise;
Power amplifying means having a predetermined output impedance, power amplifying a radio signal to be transmitted, and outputting the amplified signal to the transmission / reception antenna;
Inserted between the transmitting / receiving antenna and the low noise amplifying means and the power amplifying means, and when receiving a radio signal, outputs a radio signal from the transmitting / receiving antenna to the low noise amplifying means, while transmitting a radio signal A transmission / reception circuit comprising a sixth switching means for switching to output a radio signal from the power amplification means to the transmission / reception antenna;
The impedance is set so as to substantially match the output impedance of the power amplifying means, and is connected via the sixth switching means at a connection point between the power amplifying means and the sixth switching means. The impedance when looking at the transmission / reception antenna is the transmission antenna impedance,
Impedance set to substantially match the input impedance of the low noise amplifying means, and the phase shifting means and the sixth at the connection point between the sixth switching means and the low noise amplifying means. When the impedance when the transmission / reception antenna is viewed through the switching means is the reception antenna impedance,
A transmission / reception circuit comprising phase shifting means for phase shifting a radio signal output from the sixth switching means so that the transmission antenna impedance substantially matches the reception antenna impedance. The transceiver circuit according to any one of claims 7 to 9,
Demodulation means for demodulating the radio signal output from the low noise amplification means into a baseband signal;
A radio communication apparatus comprising: modulation means for generating a radio signal by modulating a radio carrier according to a predetermined baseband signal and outputting the radio signal to the power amplifying means.   3. The receiving circuit according to claim 1, wherein the antenna impedance of the receiving antenna is set to be higher than 50Ω.   5. The transmission circuit according to claim 3, wherein the antenna impedance of the transmission antenna is set to be lower than 50Ω. The antenna impedance of the receiving antenna is set to be higher than 50Ω,
10. The transmission / reception circuit according to claim 5, wherein an antenna impedance of the transmission antenna is set to be lower than 50Ω. The antenna impedance of the receiving antenna is set to be higher than 50Ω,
11. The wireless communication apparatus according to claim 6, wherein the antenna impedance of the transmission antenna is set to be lower than 50Ω.

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