Wireless signal processing circuit and wireless device

A wireless signal processing circuit includes plural phase switchers, plural variable amplifiers and plural mixers. The plural phase switchers are provided on each of plural paths along which all in-phase signal and a quadrature signal are distributed. The plural phase switchers rotate the phases of the signals by signal phase rotation amounts according to a transmission direction of a transmission signal. The plural variable amplifiers alter amplitudes of input signals or output signals of the corresponding phase switchers in accordance with the transmission direction of the transmission signal. The plural mixers up-convert frequencies of the signals processed by the corresponding phase switchers and variable amplifiers.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2021-074112 filed on Apr. 26, 2021, the entire content of which is incorporated herein by reference.

FIELD

The disclosed technology relates to a wireless sip al processing circuit and a wireless device.

BACKGROUND

In recent years, beamforming has been implemented at wireless devices using high frequency bands (for example, microwaves and millimeter waves), which is a technology for multiplexing transmitted and received signals or for achieving higher accuracy of sensing (radar). The technologies described below are known as technologies relating to wireless devices that employ beamforming.

For example, a wireless device is known that is provided with: a full digital array including a first antenna element group but not including an analog variable phase shifter; and a hybrid beam former including a second antenna element group and an analog variable phase shifter, in which the second antenna element group has plural antenna elements.

A wireless relay device is known that is provided with a receiving antenna, a transmitting array antenna formed with plural antenna elements, a low noise amplifier (LNA), a noise rejection bandpass filter (BPF), a mixer, a local oscillator, a narrowband BPF, an amplifier, a controller, a wireless phase shifter, an image rejection BPF and a power amplifier (PA).

An image rejection mixer is mown that is provided with a distributor that distributes an RF signal along two paths in phase, a distributor that distributes a local signal along two paths with a phase difference of 90°, and first and second mixers that mix the respective distributed outputs of the distributors. This image rejection mixer includes a pair of resistance-capacitance circuits connected in series with outputs of the first and second mixers, negative resistances connected to connection points between the respective resistances and capacitances, and an IF output terminal that suppresses image signals at one of the negative resistances.

Related Patent Documents

Patent Document 1: International Patent Publication No. 2017/135389

SUMMARY

According to an aspect of the embodiments, wireless signal processing circuit includes plural phase switchers, plural variable amplifiers and plural mixers. The plural phase switchers are provided on each of plural paths along which an in-phase signal is distributed and each of plural paths along which a quadrature signal is distributed. The in-phase signal is in phase with a transmission signal, and the quadrature signal is rotated 90° in phase from the transmission signal. Each of the plural phase switchers switches a phase rotation amount of the one of the in-phase sural and the quadrature signal that is distributed along the corresponding path selectively in accordance with a transmission direction of the transmission signal, and the phase switcher rotates the phase of the signal. The plural variable amplifiers are provided in respective correspondence with the plural phase switchers on the plural respective paths. Each of the plural variable amplifiers alters an amplitude of an input signal or output signal of the corresponding phase switcher in accordance with the transmission direction of the transmission signal. The plural mixers are provided in respective correspondence with the plural phase switchers and the plural variable amplifiers. Each of the plural mixers up-converts a frequency of the sural processed by the corresponding phase switcher and variable amplifier.

DESCRIPTION OF EMBODIMENTS

Below, examples of embodiments of the disclosure are described with reference to the drawings. Structural elements and portions that are the same or equivalent in the respective drawings are assigned the same reference symbols, and duplicative descriptions are omitted as appropriate.

A wireless device that conducts beamforming uses plural antenna elements to form beams towards each of terminals. The beamforming is realized by controlling the direction and shape of each transmission beam or reception beam, by controlling one or both of phases and Amplitudes of signals transmitted or received via the antenna elements, in accordance With a location of the corresponding terminal.

Development of wireless devices that employ beam multiplexing, in which plural different signals are superposed and beams are formed in different directions, is progressing. Full-digital-system beamforming has been proposed as a method for realizing beam multiplexing.

In full-digital-system beamforming, one or both of the phases and amplitudes of signals transmitted or received via antenna elements is controlled by digital processing. Accordingly, in order to form transmission beams, a wireless device conducting full-digital beamforming is equipped with a digital-analog converter (DAC) for each antenna element. That is, a wireless device that performs full-digital-system beamforming is equipped with the same number of DACs as of antenna elements. Further, in order to form reception beams, the wireless device that performs full-digital beamforming is equipped with the same number of analog-digital converter (ADCs) as of antenna elements. The power consumptions of these DACs and ADCs depend on data signal rates. Therefore, when a wireless device that performs full-digital-system beamforming is employed in, for example, a wideband communications system employing the millimeter wave band or the like, data signal rates are high and power consumption is large.

An analog full-connection system has been proposed as an alternative system for realizing beamforming.FIG.1is a diagram showing an example of structures of a wireless device that conducts analog full-connection-system beamforming (a first reference example).

A wireless device10X illustrated inFIG.1is equipped with four DACs12for dealing with four terminals (not depicted in the drawing). Each DAC12converts a transmission signal to be transmitted to the corresponding terminal to an analog signal. It is preferable if the wireless device10X is equipped with a greater number of antenna elements than the number of terminals (that is, the number of transmission signals). In the example depicted inFIG.1, the wireless device10X is provided with eight antenna elements AN. In this configuration, transmission signals ST1to ST4in a baseband range or intermediate frequency band are to be transmitted to the terminals. A local signal LO is used to up-convert the transmission signals ST1to ST4to a radio frequency (RF) band, and the transmission signals ST1to ST4are then distributed to eight wireless signal processing circuits20X that are provided in correspondence with the antenna elements AN. Each wireless signal processing circuit20X controls the phases of the corresponding transmission signal ST1to ST4. Output signals froth the wireless signal processing circuits20X are outputted via the respective corresponding antenna elements AN. The wireless signal processing circuits20X form beams that correspond with the respective terminals by controlling the phases of the transmission signals ST1to ST4in accordance with locations of the terminals.

According to the analog full-connection system, it is sufficient to provide a number of the DACs12that corresponds with the number of terminals (the number of signals). Thus, the number of DACs may be reduced in comparison with a full-digital system and power consumption may be restrained. However, according to the analog full-connection system, numerous signal lines between the plural DACs12and the plural wireless signal processing circuits20X cross over. In the example depicted inFIG.1, 32 signal lines are provided between the four DACs12and the eight wireless signal processing circuits20X, and relatively high frequency RF band signals are propagated through these signal lines. Consequently, transmission losses are large and practical implementation is difficult.

To solve the problem described above, for example, adding loss correction circuits can be considered. However, when a reduction in size of the wireless device is called for, adding loss correction circuits increases circuit size (areas occupied by circuitry) and is therefore not preferable. Moreover, adding, loss correction circuits may increase power consumption.

First Exemplary Embodiment

FIG.2is a diagram showing an example of structures of a wireless system200according to an exemplary embodiment of the disclosed technology. The wireless system200is provided with a wireless device10and plural terminals101,102,103and104. The wireless device10is not particularly limited and may be, for example, mounted at a wireless system base station, in which case the terminals101to104are user terminals such as smartphones or the like. In the present exemplary embodiment, the number of terminals dealt with by the wireless system200is four, but the number of terminals dealt with by the wireless system200may increase or decrease as appropriate. The wireless device10is capable of forming transmission beams for transmitting signals to the terminals101to104and reception beams for receiving signals from the terminals101to104. That is, the wireless device10features functions for forming transmission beams to transmit signals and functions for forming reception beams to receive signals. Below, mainly functions far receiving signals are described.

The wireless device10is supplied with transmission signals ST1to ST4to be transmitted to the terminals101to104. The wireless device10forms the transmission signals ST1to ST4into transmission beams B1to B4for transmission to, respectively, the terminals101to104. The transmission beam B1is formed so as to propagate the transmission signal ST1from the wireless device10to the terminal101. Accordingly, the transmission beam B1is formed in a direction from the wireless device10toward the terminal101. Similarly, the transmission beams B2to B4are formed so as to propagate the transmission signals ST2to ST4from the wireless device10to, respectively, the terminals102to104. In this manner, the wireless device10may form the plural transmission beams B1to B4corresponding with the terminals101to104simultaneously. The wireless device10individually controls the radiation directions and shapes of the transmission beams B1to B4in accordance with locations of the terminals101to104. That is, the wireless device10implements beam multiplexing.

FIG.3is a diagram showing an example of structures of the wireless device10according to the exemplary embodiment of the disclosed technology. The wireless device10is provided with a plural number of wireless signal processing circuits20, the plural number of antenna elements AN, and a controller30. Reception circuits for forming reception beams are not depicted inFIG.3. It is preferable if the wireless device10is provided with a greater number of the antenna elements AN than a number of terminals to be dealt with by the wireless system200. In the present exemplary embodiment, eight of the antenna elements AN are provided at the wireless device10to correspond with the four terminals101to104being dealt with by the wireless system200. The antenna elements AN are disposed in an array pattern. That is, the wireless device10is equipped with an array antenna system. The plural antenna elements AN may be arranged in a single row, and may be arranged in a matrix pattern so as to form rows and columns. Further, the antennas may be arranged in three dimensions.

The wireless signal processing circuits20are provided in respective correspondence with the plural antenna elements AN. That is, the number of wireless signal processing circuits20provided at the wireless device10is the same as the number of the antenna elements AN, which is eight in the present exemplary embodiment. The transmission signals ST1to ST4are analog signals in a baseband range or an intermediate frequency band. Frequencies of the transmission signals ST1to ST4are not particularly limited but are, as an example, around 3 GHz. When the transmission signals provided to the wireless device10are digital signals, the wireless device10is provided with DACs that convert the digital signals to analog signals. The transmission signals ST1to ST4that have been converted to analog signals by the DACs are respectively distributed to the eight wireless signal processing circuits20. The wireless signal processing circuits20respectively form the transmission beams B1to B4for transmitting the transmission signals ST1to ST4to the corresponding terminals101to104, by performing phase control of the transmission signals ST1to ST4using weightings W provided from the controller30. That is, the wireless device10conducts beamforming with an analog full-connection system that distributes the transmission signals ST1to ST4to be transmitted to the terminals101to104to all of the wireless signal processing circuits20provided at the wireless device10to form the transmission beams B1to B4.

The controller30generates the weightings W for phase control at the respective wireless signal processing circuits20on the basis of locations of the terminals101to104. The respective wireless signal processing circuits20use the weightings W generated by the controller30to apply phase control represented by the following expression (1) to the transmission signals ST1to ST4, and output signals Sout1to Sout8.

For example, the output signal Sout1that is outputted from one of the eight wireless signal processing circuits20is expressed by the following expression (2).
Sout1=W1,1·ST1+W1,2·ST2+W1,3·ST3+W1,4·ST4   (2)

On the basis of the location of the terminal101, the controller30generates weightings W1,1, W2,1, W3,1, W4,1, W5,1, W6,1, W7,1and W8,1. On the basis of the location of the terminal102, the controller30generates weightings W1,2, W2,2, W3,2, W4,2, W5,2, W6,2, W7,2and W8,2. On the basis of the location of the terminal103, the controller30generates weightings W1,3, W2,3, W33, W4,3, W5,3, W6,3, W7,3and W8,3. On the basis of the location of the terminal104, the controller30generates weightings W1,4, W2,4, W3,4, W4,4, W5,4, W6,4, W7,4and W8,4. The weightings W are updated in accordance with changes in locations of the terminals101to104and changes in communication conditions between the wireless device10and the terminals101to104.

The respective wireless signal processing circuits20use a local signal LO to up-convert the transmission signals ST1to ST4in the baseband range or intermediate frequency band to an RF band (or millimeter wave band), and output the up-converted signals as the output signals Sout1to Sout8. The output signals Sout1to Sout8are radiated from the respectively corresponding antenna elements AN. The transmission beams B1to B4are formed towards the terminals101to104by the output signals Sout1to Sout8whose phases have been controlled being radiated from the eight respective antenna elements AN. That is, the wireless device10constitutes an array antenna system and forms the transmission beams B1to B4.

FIG.4is a diagram showing an example of structures of each wireless signal processing circuit20. The structures of the plural wireless signal processing circuits20are the same as one another. Of the eight wireless signal processing circuits20.FIG.4illustrates the wireless signal processing circuit20that outputs the output signal Sout1. The wireless signal processing circuit20is provided with plural phase control sections40, plural mixer sections50and a combination portion60. The plural phase control sections40and the plural mixer sections50are provided in respective correspondence with the transmission signals ST1to ST4to be transmitted to the terminals101to104.

A passive circuit region of each phase control section40includes, for example, at least one of a lumped element circuit or a circuit conforming to a lumped element model such as a spiral inductor or meander inductor. On the basis of a weighting W provided from the controller30, the phase control section40controls the phase of the corresponding transmission signal in accordance with a transmission direction of the corresponding transmission signal (a radiation direction of the corresponding transmission beam). The phase control section40is provided with a phase rotation section400, a first phase switching section410a, a second phase switching section410b, a first variable amplifier420aand a second variable amplifier420b. The phase control section40distributes the corresponding transmission signal along two paths, supplying one distributed signal to the first phase switching section410aand supplying the other to the phase rotation section400.

The corresponding transmission signal among the transmission signals ST1to ST4is supplied to each first phase switching section410awithout the phase thereof being rotated. That is, an in-phase signal ST1-I that is in phase with the transmission signal ST1is supplied to the first phase switching section410acorresponding to the transmission signal ST1. Similarly, in-phase signals ST2-I to ST4-I are supplied to the first phase switching sections410acorresponding to the transmission signals ST2to ST4. Each first phase switching section410aswitches a phase rotation amount of the corresponding in-phase signal selectively in accordance with the transmission direction of the corresponding transmission signal, and the first phase snitching section410arotates the phase of the in-phase signal in correspondence with the selected rotation amount. For example, the first phase switching section410acorresponding to the transmission signal ST1selectively switches the phase rotation amount of the in-phase signal ST1-I in accordance with the transmission direction of the transmission signal ST1(the radiation direction of the transmission beam B1) and rotates the phase of the in-phase signal ST1-I. Similarly, the first phase switching sections410acorresponding to the transmission signals ST2to ST4selectively switch phase rotation amounts of the in-phase signals ST2-I to ST4-I in accordance with the transmission directions of the transmission signals ST2to ST4(the radiation directions of the transmission beams B2to B4) and rotate the phases of the in-phase signals ST2-I to ST4-I.

Each phase rotation section400rotates the phase of the corresponding transmission signal among the transmission signals ST1to ST4by 90°. Below, a transmission signal whose phase has been rotated 90° by the phase rotation section400is referred to as the quadrature signal. That is, the phase rotation section400corresponding to the transmission signal ST1outputs a quadrature signal ST1-Q. Similarly, the phase rotation sections400corresponding to the transmission signals ST2to ST4output respective quadrature signals ST2-Q to ST4-Q. The quadrature signals ST1-Q to ST4-Q are supplied to the corresponding second phase switching sections410b.

Each second phase switching section410bswitches a phase rotation amount of the corresponding quadrature signal selectively in accordance with the transmission direction of the corresponding transmission signal, and the second phase switching section410brotates the phase of the quadrature signal in correspondence with the selected rotation amount. For example, the second phase switching section410bcorresponding to the transmission signal ST1selectively switches the phase rotation amount of the quadrature signal ST1-Q in accordance with the transmission direction of the transmission signal ST1(the radiation direction of the transmission beam B1) and rotates the phase of the quadrature signal ST1-Q. Similarly, the second phase switching sections410bcorresponding to the transmission signals ST2to ST4selectively switch phase rotation amounts of the quadrature signals ST2-Q to ST4-Q in accordance with the transmission directions of the transmission signals ST2to ST4(the radiation directions of the transmission beams B2to B4) and rotate the phases of the quadrature signals ST2-Q to ST4-Q. The phase rotation amounts of the first phase switching section410aand second phase switching section410bare set to 0° or 180° in accordance with the weightings W provided from the controller30.

Each first variable amplifier420aalters the amplitude of the output signal of the first phase switching section410ain accordance with the transmission direction of the corresponding transmission signal. For example, the first variable amplifier420acorresponding to the transmission signal ST1alters the amplitude of the in-phase signal ST1-I whose phase has been rotated by 0° or 180° in accordance with the transmission direction of the transmission signal ST1. Similarly, the first variable amplifiers420acorresponding to the transmission signals ST2to ST4alter the respective amplitudes of the in-phase signals ST2-I to ST4-I whose phases have been rotated by 0° or 180° in accordance with the transmission directions of the transmission signals ST2to ST4.

Each second variable amplifier420balters the amplitude of an output signal of the second phase switching section410bin accordance with the transmission direction of the corresponding transmission signal. For example, the second variable amplifier420bcorresponding to the transmission signal ST1alters the amplitude of the quadrature signal ST1-Q whose phase has been rotated by 0° or 180° in accordance with the transmission direction of the transmission signal ST1. Similarly, the second variable amplifiers420bcorresponding to the transmission signals ST2to ST4alter the respective amplitudes of the quadrature signals ST2-Q to ST4-Q whose phases have been rotated by 0° or 180° in accordance with the transmission directions of the transmission signals ST2to ST4. Amplitude alteration ratios (amplification factor) of the first variable amplifier420aand second variable amplifier420bare set in accordance with the weightings W provided from the controller30.

The plural mixer sections50are provided in respective correspondence with the plural phase control sections40and up-convert the frequencies of the transmission signals whose phases have been controlled by the phase control sections40. Each mixer section50is provided with a first mixer500aand a second mixer500b. The first mixer500aup-converts the frequency of an output signal of the first variable amplifier420ausing a local signal LO with a higher frequency than the frequencies of the transmission signals ST1to ST4. The second mixer500buses the local signal LO to up-convert the frequency of an output signal of the second variable amplifier420b. Each of the plural mixer sections50uses the common local signal LO. The transmission signals ST1to ST4in the baseband range or intermediate frequency band are up-converted to the RF band (or millimeter wave band) by the mixer sections50. The frequency of the local signal LO is not particularly limited but may be, for example, around 25 GHz. Local terminals at which the local signal LO is fed into the first and second mixers500aand500bare common (connected together), and RF terminals at which RF signals are fed out are common (connected together).

The combination portion60is a conduction path connecting the outputs of the plural mixer sections50with one another. That is, the transmission signals ST1to ST4are respectively controlled in phase at the corresponding phase control sections40, altered in frequency at the corresponding mixer sections50, and then combined at the combination portion60. Thus, the output signals Sout1to Sout8are generated at the respective wireless signal processing circuits20. Each combination portion60is connected to the corresponding antenna element AN, and the output signals Sout1to Sout8are radiated from the corresponding antenna elements AN.

The phases of the transmission signals ST1to ST4can be switched in quadrants by settings of the phase rotation amounts at the first and second phase switching sections410aand410b. In accordance with settings of the amplitude alteration ratios (amplification factors) at the first and second variable amplifiers420aand420b, phase rotation amounts of the transmission signals ST1to ST4may be controlled in ranges from 0° to 360°. That is, the phase control sections40control the phase rotation amounts of the transmission signals ST1to ST4in ranges from 0° to 360° by vector composition of the in-phase signals and quadrature signals that have been phase-switched and amplitude-controlled.

For example, if the phase rotation amount of the corresponding transmission signal ST1to ST4at each phase control section40is to be controlled in a range from 0° to 90° (a first quadrant), 0° is selected as the phase rotation amount at the first phase switching section410a, and 0° is selected as the phase rotation amount at the second phase switching section410b. The phase rotation amount of the transmission signal ST1to ST4can be controlled in the range from 0° to 90° according to a ratio of the amplification factors at the first and second variable amplifiers420aand420b.

Alternatively, for example, if the phase rotation amount of the corresponding transmission signal ST1to ST4at the phase control section40is to be controlled in a range from 90° to 180° (a second quadrant), 180° is selected as the phase rotation amount at the first phase switching section410a, and 0° is selected as the phase rotation amount at the second phase switching section410b. The phase rotation amount of the transmission signal ST1to ST4can be controlled in the range from 90° to 180° according to the ratio of the amplification factors at the first and second variable amplifiers420aand420b.

If, for example, the phase rotation amount of the corresponding transmission signal ST1to ST4at the phase control section40is to be controlled in a range from 180° to 270° (a third quadrant), 180° is selected as the phase rotation amount at the first phase switching section410a, and 180° is selected as the phase rotation amount at the second phase switching section410b. The phase rotation amount of the transmission signal ST1to ST4can be controlled in the range from 180° to 270° according to the ratio of the amplification factors at the first and second variable amplifiers420aand420b.

If, for example, the phase rotation amount of the corresponding transmission signal ST1to ST4at the phase control section40is to be controlled in a range from 270° to 360° (a fourth quadrant), 0° is selected as the phase rotation amount at the first phase switching section410a, and 180° is selected as the phase rotation amount at the second phase switching section410b. The phase rotation amount of the transmission signal ST1to ST4can be controlled in the range from 270° to 360° according to the ratio of the amplification factors at the first and second variable amplifiers420aand420b.

The amplitude of each transmission signal ST1to ST4may be changed by changing the amplification factors of the first and second variable amplifiers420aand420bwhile keeping the ratio of the amplification factors fixed. That is, all elements of the weightings W may apply weighting to the amplitudes as well as the phases. For example, by weighting the amplitudes, respective beam shapes such as beam widths and the like of the transmission beams B1to B4may be changed.

According to the wireless device10X according to the first reference example depicted inFIG.1, the transmission signals ST1to ST4to be transmitted to the terminals are up-converted to the RF band using the local signal LO and are then distributed to the plural wireless signal processing circuits20X. According to the wireless device10X according to the first reference example, 32 signal lines are provided between the four DACs12and the eight wireless signal processing circuits20X, and signals with relatively high frequencies in the RF band are propagated through these signal lines. Therefore, signal losses are large.

In contrast, according to the wireless device10according to this exemplary embodiment of the disclosed technology, distribution of the transmission signals ST1to ST4to the wireless signal processing circuits20is conducted at relatively low frequencies in the baseband range or intermediate frequency band. Therefore, according to the wireless device10provided with the wireless signal processing circuits20according to the exemplary embodiment of the disclosed technology, signal losses may be smaller than in the wireless device10X provided with the wireless signal processing circuits20X according to the first reference example.

FIG.5is a diagram showing an example of structures of a wireless signal processing circuit20Y according to a second reference example. The wireless signal processing circuits20Y are provided in respective correspondence with plural antenna elements AN. Each wireless signal processing circuit20Y has similar fluid to the wireless signal processing circuit20according to the exemplary embodiment of the disclosed technology described above. The wireless signal processing circuit20Y is provided with a plural number of amplitude control sections70, a plural number of mixer sections50Y, and the combination portion60. The plural amplitude control sections70and the plural mixer sections50Y are provided in respective correspondence with the transmission signals ST1to ST4.

Each amplitude control section70alters the amplitude of the corresponding transmission signal in accordance with the transmission direction of the transmission signal. The amplitude control section70is provided with a first variable amplifier700aand a second variable amplifier700b. The amplitude control section70distributes the corresponding transmission signal along two paths, supplying one distributed signal to the first variable amplifier700aand supplying the other to the second variable amplifier700b.

The first and second variable amplifiers700aand700balter respective amplitudes of the corresponding transmission signal in accordance with the transmission direction of the transmission signal. For example, the first and second variable amplifiers700aand700bcorresponding to the transmission signal ST1alter the amplitudes of the transmission signal ST1in accordance with the transmission direction of the transmission signal ST1. Amplitude alteration ratios (amplification factors) of the first and second variable amplifiers700aand700bare set in accordance with the weightings W provided from the controller30.

Each of the plural mixer sections50Y is provided with a first phase switching section510a, a second phase switching section510b, the first mixer500aand the second mixer500b. Each of the first and second phase switching sections510aand510bswitches a phase rotation amount of the local signal LO selectively in accordance with the transmission direction of the corresponding transmission signal, and the first and second phase switching sections510aand510brotate the phase of the local signal LO by the selected rotation amounts. A phase rotation amount at the first phase switching section510ais set to 90° or 270° in accordance with the weighting W provided from the controller30. A phase rotation amount at the second phase switching section510bis set to 0° or 180° in accordance with the weighting W provided from the controller30.

The first mixer500auses the local signal LO whose phase has been rotated by the first phase switching section510ato up-convert the frequency of the output signal from the first variable amplifier700a. The second mixer500buses the local signal LO whose phase has been rotated by the second phase switching section510bto up-convert the frequency of the output signal from the second variable amplifier700b. Thus, the transmission signals ST1to ST4in the baseband range or intermediate frequency band are up-converted to the RF band (or millimeter wave band) by the mixer sections50Y.

The transmission signals ST1to ST4whose amplitudes have been controlled at the corresponding amplitude control sections70and whose frequencies have been converted at the corresponding mixer sections50Y are then combined at the combination portion60. Thus, the output signals Sout1to Sout8are generated at the respective wireless signal processing circuits20Y.FIG.5shows the wireless signal processing circuit20Y that outputs the output signal Sout1as an example. Each combination portion60is connected to the corresponding antenna element AN, and the output signals Sout1to Sout8are radiated from the corresponding antenna elements N.

The phases of the transmission signals ST1to ST4can be switched in quadrants by settings of the phase rotation amounts at the first and second phase switching sections510aand510b. In accordance with settings of the amplitude alteration ratios (amplification factors) at the first and second variable amplifiers700aand700b, phase rotation amounts of the transmission signals ST1to ST4can be controlled in ranges from 0° to 360°.

According to the wireless signal processing circuit20Y according to the second reference example, similarly to the wireless signal processing circuit20according to the exemplary embodiment of the disclosed technology, transmission beams towards the terminals101to104may be formed. In addition, distribution of the transmission signals ST1to ST4to the wireless signal processing circuits20Y is conducted at relatively low frequencies in the baseband range or intermediate frequency band. Therefore, signal losses may be smaller than in the wireless device10X according to the first reference example depicted inFIG.1.

However, according to the wireless signal processing circuit20Y according to the second reference example, as depicted inFIG.6, a number of high-frequency blocks HF through which the local signal LO is propagated with a relatively high frequency is large. For example, in a structure dealing with the four transmission signals ST1to ST4, the number of the high-frequency blocks HF is five, as depicted inFIG.5. Each high-frequency block HF is constituted with a distributed element circuit of a size corresponding with the wavelength of the high-frequency signal. Therefore, it is difficult to constitute the wireless signal processing circuit20Y according to the second reference example with a smaller circuit size (areas occupied by circuitry). For example, if the circuit described above is constituted in a semiconductor integrated circuit and the high-frequency wavelength is close to the size of the semiconductor integrated circuit, the plural high-frequency blocks HF occupy most of interior regions of the semiconductor integrated circuit or are larger than the integrated circuit area.

In contrast, according to the wireless signal processing circuit20according to the exemplary embodiment of the disclosed technology, as depicted inFIG.7, the number of high-frequency blocks HF may be kept to one. In addition, the mixers structuring the mixer sections may be constituted by transistors500. The drains (or sources) of the transistors500are connected in common to the combination portion60, and the local signal LO is supplied in common to the gates of the transistors500. Therefore, the transistor500structuring each mixer may be constituted by a single multifinger transistor provided with a single drain electrode (or source electrode), a single gate electrode, and a plural number of source electrodes (or drain electrodes) that are separated from one another. Thus, the plural mixer sections50may be structured very compactly. That is, according to the wireless signal processing circuit20according to the exemplary embodiment of the disclosed technology, the circuit size (areas occupied by circuitry) may be smaller than the wireless signal processing circuit20Y according to the second reference example.

According to the wireless signal processing circuit20according to the exemplary embodiment of the disclosed technology, because the transmission signals ST1to ST4that are propagated to the phase control sections40are signals with relatively low frequencies in the baseband range or intermediate frequency band, a passive circuit of each phase control section40may be structured with a lumped element circuit or a circuit conforming to a lumped element model. The term “a circuit conforming to a lumped element model” as used herein is intended to include circuits that include distributed element model elements such as spiral inductors and meander inductors, but encompasses circuits that may be constituted with small areas. Because the passive elements of the phase control section40are constituted by a lumped element circuit or a circuit conforming to a lumped element model, the circuit size (areas occupied by circuitry) of the wireless signal processing circuit20may be made relatively small.

FIG.4shows a structure in which the first and second variable amplifiers420aand420bare disposed at the respective output sides of the first and second phase switching sections410aand410b, but this is not limiting. As illustrated inFIG.8, the first and second variable amplifiers420aand420bmay be disposed at the respective input sides of the first and second phase switching sections410aand410b.

Second Exemplary Embodiment

FIG.9is a diagram showing an example of structures of a wireless signal processing circuit20A according to a second exemplary embodiment of the disclosed technology. The wireless signal processing circuits20A are provided in respective correspondence with plural antenna elements AN.

The wireless signal processing circuit20A includes a plural number of phase rotation sections80. The plural phase rotation sections80are provided respective correspondence with the transmission signals ST1to ST4. Each phase rotation section80rotates the phase of the corresponding transmission signal by 90°. That is, the phase rotation section80corresponding to the transmission signal ST1outputs the quadrature signal ST1-Q. Similarly, the phase rotation Sections80corresponding to the transmission signals ST2to ST4output respective quadrature signals ST2-Q to ST4-Q.

In the wireless signal processing circuit20A, each of a plural number of phase control sections provided in respective correspondence with the transmission signals ST1to ST4includes first to fourth phase switching sections410ato410dand first to fourth variable amplifiers420ato420d.

The first and third phase switching sections410aand410crespectively switch phase rotation amounts of the corresponding in-phase signal selectively in accordance with the transmission direction of the corresponding transmission signal, and the first and third phase switching sections410aand410crotate the phase of the in-phase signal in correspondence with the selected rotation amounts. For example, the first and third phase switching sections410aand410ccorresponding to the transmission signal ST1selectively switch phase rotation amounts of the in-phase signal ST1-I in accordance with the transmission direction of the transmission signal ST1and rotate the phase of the in-phase signal ST1-I.

The second and fourth phase switching sections410band410drespectively switch phase rotation amounts of the corresponding quadrature signal selectively in accordance with the transmission direction of the corresponding transmission signal, and the second and fourth phase switching sections410band410drotate the phase of the quadrature signal in correspondence with the selected rotation amounts. For example, the second and fourth phase switching sections410band410dcorresponding to the transmission signal ST1selectively switch phase rotation amounts of the quadrature signal ST1-Q in accordance with the transmission direction of the transmission signal ST1and rotate the phase of the quadrature signal ST1-Q. The phase rotation amounts of the first to fourth phase switching sections410ato410dare set to 0° or 180° in accordance with the weightings W provided from the controller30.

Each first variable amplifier420aalters the amplitude of the output signal of the first phase switching section410ain accordance with the transmission direction of the corresponding transmission signal. Similarly, the second to fourth variable amplifiers420bto420dalter the respective amplitudes of the output signals of the second to fourth phase switching sections410bto410din accordance with the transmission direction of the corresponding transmission signal. Amplitude alteration ratios (amplification factors of the first to fourth variable amplifiers420ato420dare set in accordance with the weightings W provided from the controller30.

In the wireless signal processing circuit20A, plural mixer sections that are provided in respective correspondence with the transmission signals ST1to ST4each include first to fourth mixers500ato500d. The first mixer500aup-converts the frequency of the output signal of the first variable amplifier420ausing a first local signal LO-I with a higher frequency than the frequencies of the transmission signals ST1to ST4. The second mixer500buses the first local signal LO-I to up-convert the frequency of the output signal of the second variable amplifier420b. That is, the first and second mixers500aand500buse the first local signal LO-I in common to up-convert the frequency.

The third mixer500cup-converts the frequency of the output signal of the third variable amplifier420cusing a second local signal LO-Q, which is rotated in phase by 90° relative to the first local signal LO-I. The fourth mixer500duses the second local signal LO-Q to up-convert the frequency of the output signal of the fourth variable amplifier420d. That is, the third and fourth mixers500cand500duse the second local signal LO-Q in common to up-convert the frequency.

The transmission signals ST1to ST4are respectively controlled in phase at the corresponding phase control sections (the first to fourth phase switching sections410ato410dand the first to fourth variable amplifiers420ato420d), altered in frequency at the corresponding mixer sections (the first to fourth mixers500ato500d), and then combined at the combination portion60. Thus, the output signals Sout1to Sout8are generated at the respective wireless signal processing circuits20A. Each combination portion60is connected to the corresponding antenna element AN, and the output signals Sout1to Sout8are radiated from the corresponding antenna elements AN.FIG.9shows the wireless signal processing circuit20A that outputs the output signal Sout1as an example.

Now, when the frequencies of the transmission signals ST1to ST4in the baseband range or intermediate frequency band are up-converted by use of the mixers to mix the transmission signals ST1to ST4with the local signals, image signals are introduced into the output signals of the mixers. Image signals are interference signals occurring with a desired signal in a target frequency range, which are centered on the frequency band of the local signal. The image signals may be suppressed by mixing the in-phase signals ST1-I to ST4-I and the quadrature signals ST1-Q to ST4-Q With the two local signals LO-I and LO-Q that ate orthogonal to one another at the mixers and then combining these signals.

The wireless signal processing circuit20A has a structure in which the third and fourth phase switching sections410cand410d, the third and fourth variable amplifiers420cand420d, and the third and fourth mixers500cand500dare added to the wireless signal processing circuit20according to the first exemplary embodiment. Thus, image signals may be suppressed by processing that mixes the in-phase signals ST1-I to ST4-I and quadrature signals ST1-Q to ST4-Q with the two local signals LO-I and LO-Q that are orthogonal to one another and combines the up-converted signals.

In the wireless signal processing circuit20A, the in-phase signals ST1-I to ST4-I and quadrature signals ST1-Q to ST4-Q are used in switching the phases of the transmission signals ST1to ST4to the four quadrants and are used for suppression of image signals. Thus, because the in-phase sisals and quadrature signals are used for both phase control and image signal suppression, an increase in circuit size (areas occupied by circuitry) may be suppressed.

According to the wireless signal processing circuit20A, similarly to the wireless signal processing circuit20according to the first exemplary embodiment, distribution of the transmission signals ST1to ST4to the wireless signal processing circuits20A is conducted at relatively low frequencies in the baseband range or intermediate frequency band. Therefore, according to the wireless device10equipped with the wireless signal processing circuits20A, signal losses may be smaller than in the wireless device10X according to the first reference example. Further, according to the wireless signal processing circuit20A, similarly to the wireless signal processing circuit20according to the first exemplary embodiment, the number of high-frequency blocks HF may be reduced and thus an increase in circuit size (areas occupied by circuitry) may be suppressed. Local terminals at which the first local signal LO-I is inputted to the first and second mixers500aand500bare common (connected together) and local terminals at which the second local signal LO-Q is inputted to the third and fourth mixers500cand500dare common (connected together). RF terminals at which RF signals are outputted from the first to fourth mixers500ato500dare common (connected together). Therefore, the mixer sections may be constituted by, for example, multifinger transistors, and the mixer sections may be structured very compactly.

In a modification of the example depicted inFIG.8, the first to fourth variable amplifiers420ato420dmay be disposed at the respective input sides of the first to fourth phase switching sections410ato410d.

Third Exemplary Embodiment

FIG.10is a diagram showing an example of structures of a wireless signal processing circuit20B according to a third exemplary embodiment of the disclosed technology. The wireless signal processing circuits20B are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20B has a structure in which a function that suppresses image signals is added to the wireless signal processing circuit20Y according to the second reference example depicted inFIG.5.

The wireless signal processing circuit20B includes a plural number of the phase rotation sections80, a plural number of first amplitude control sections70A, a plural number of second amplitude control sections70B, a plural number of first mixer sections50A, a plural number of second mixer sections50B, and the combination portion60.

The plural phase rotation sections80are provided in respective correspondence with the transmission signals ST1to ST4. Each phase rotation section80rotates the phase of the corresponding transmission signal by 90°. That is, the phase rotation section80corresponding to the transmission signal ST1outputs the quadrature signal ST1-Q. Similarly, the phase rotation sections80corresponding to the transmission signals ST2to ST4output respective quadrature signals ST2-Q to ST4-Q.

The plural first amplitude control sections70A and the plural first mixer sections50A are provided in respective correspondence with the transmission signals ST1to ST4. Similarly, the plural second amplitude control sections70B and the plural second mixer sections50B are provided in respective correspondence with the transmission signals ST1to ST4.

Each first amplitude control section70A alters the amplitude of the corresponding transmission signal. The first amplitude control section70A is provided with the first variable amplifier700aand second variable amplifier700b. The first amplitude control section70A distributes the corresponding transmission signal along two paths, supplying one distributed signal to the first variable amplifier700aand supplying the other to the second variable amplifier700b.

The first and second variable amplifiers700aand700balter respective amplitudes of the corresponding transmission signal in accordance with the transmission direction of the transmission signal. For example, the first and second variable amplifiers700aand700bcorresponding to the transmission signal ST1alter respective amplitudes of the in-phase signal ST1-1that is in phase with the transmission signal ST1in accordance with the transmission direction of the transmission signal ST1. Amplitude alteration ratios (amplification factors) of the first and second variable amplifiers700aand700bare set in accordance with the weightings W provided from the controller30.

Each second amplitude control section70B alters the amplitude of the quadrature signal whose phase has been rotated 90° from the corresponding transmission signal. The second amplitude control section70B is provided with a third variable amplifier700cand a fourth variable amplifier700d. The second amplitude control section70B distributes the corresponding quadrature signal along two paths, Supplying one distributed signal to the third variable amplifier700cand supplying the other to the fourth variable amplifier700d.

The third and fourth variable amplifiers700cand700dalter respective amplitudes of the corresponding quadrature signal in accordance with the transmission direction of the corresponding transmission signal. For example, the third and fourth variable amplifiers700cand700dcorresponding to the transmission signal ST1alter respective amplitudes of the quadrature signal ST1-Q, whose phase is rotated 90° from the transmission signal ST1, in accordance with the transmission direction of the transmission signal ST1. Amplitude alteration ratios (amplification factors) of the third and fourth variable amplifiers700cand700dare set in accordance with the weightings W provided from the controller30.

Each of the plural first mixer sections50A is provided with the first phase switching section510a, the first mixer500a, the second phase switching section510band the second mixer500b. Each of the first and second phase switching sections510aand510bselectively switches a phase rotation amount of the first local signal LO-I in accordance with the transmission direction of the corresponding transmission signal, and the first and second phase switching sections510aand510brotate the phase of the first local signal LO-I by the selected rotation amounts. A phase rotation amount at the first phase switching section510ais set to 90° or 270° in accordance with the weighting W provided from the controller30. A phase rotation amount at the second phase switching section510bis set to 0° or 180° in accordance with the weighting W provided from the controller30.

The first mixer500auses the first local signal LO-I whose phase has been rotated by the first phase switching section510ato up-convert the frequency of the output signal from the first variable amplifier700a. The second mixer500buses the first local signal LO-I whose phase has been rotated by the second phase switching section510bto up-convert the frequency of the output signal from the second variable amplifier700b. Thus, the transmission signals ST1to ST4in the baseband range or intermediate frequency band are up-converted to the RF band (or millimeter wave band) by the plural first mixer sections50A.

Each of the plural second mixer sections50B is provided with a third phase switching section510c, the third mixer500c, a fourth phase switching section510dand the fourth mixer500d. Each of the third and fourth phase switching sections510cand510dselectively switches a phase rotation amount of the second local signal LO-Q, whose phase is rotated 90° relative to the first local signal LO-I, in accordance with the transmission direction of the corresponding transmission signal, and the third and fourth phase switching sections510cand510drotate the phase of the second local signal LO-Q by the selected rotation amounts. A phase rotation amount at the third phase switching section510cis set to 90° or 270° in accordance with the weighting W provided from the controller30. A phase rotation amount at the fourth phase switching section510dis set to 0° or 180° in accordance with the weighting W provided froth the controller30.

The third mixer500cuses the second local signal LO-Q whose phase has been rotated by the third phase switching section510cto up-convert the frequency of the output signal from the third variable amplifier700c. The fourth mixer500duses the second local signal LO-Q whose phase has been rotated by the fourth phase switching section510dto up-convert the frequency of the output signal from the fourth variable amplifier700d. Thus, the transmission signals ST1to ST4in the baseband range or intermediate frequency band are up-converted to the RF band (or millimeter wave band) by the second mixer sections50B.

The transmission signals ST1to ST4whose amplitudes have been controlled at the corresponding first and second variable amplifiers700aand700band whose frequencies have been converted at the corresponding first and second mixer sections50A and50B are then combined at the combination portion60. Thus, the output signals Sout1to Sout8are generated at the respective wireless signal processing circuits20B.FIG.10shows the wireless signal processing circuit20B that outputs the output signal Sout1as an example. Each combination portion60is connected to the corresponding antenna element AN, and the output signals Sout1to Sout8are radiated from the corresponding antenna elements AN.

The phases of the transmission signals ST1to ST4can be switched in quadrants by settings of the phase rotation amounts at the first to fourth phase switching sections510ato510d. In accordance with settings of the amplitude alteration ratios (amplification factors) at the first to fourth variable amplifiers700ato700d, phase rotation amounts of the transmission signals may be controlled in ranges from 0° to 360°.

According to the wireless signal processing circuit20B, similarly to the wireless signal processing circuit20according to the first exemplary embodiment of the disclosed technology, transmission beams may be formed towards respective terminals. In addition, distribution of the transmission signals ST1to ST4to the wireless signal processing circuit20B is conducted at relatively low frequencies in the baseband range or intermediate frequency band. Therefore, signal losses may be smaller than in the wireless device10X according to the first reference example (seeFIG.1).

The wireless signal processing circuit20B has a structure in which the third and fourth phase switching sections510cand510d, the third and fourth variable amplifiers700cand700d, and the third and fourth mixers500cand500dare added to the wireless signal processing circuit20Y according to the second reference example (seeFIG.5). Thus, image signals may be suppressed by processing that mixes the in-phase signals ST1-I to ST4-I and quadrature signals ST1-Q to ST4-Q with the two local signals LO-I and LO-Q that are orthogonal to one another and combines the up-converted signals.

Fourth Exemplary Embodiment

FIG.11is a diagram Showing an example of structures of a wireless signal processing circuit20C according to a fourth exemplary embodiment of the disclosed technology. The wireless signal processing circuits20C are provided in respective correspondence with the plural antenna elements AN. The wireless signal processing circuits20,20A and20B according to the first to third exemplary embodiments described above feature functions that form the transmission beams B1to B4towards the terminals101to104and transmit the transmission signals ST1to ST4. In contrast, the wireless signal processing circuit20C according to the present exemplary embodiment features functions for forming reception beams of respective signals transmitted from the terminals101to104(below referred to as reception signals SR1to SR4) and receiving the reception beams.

The wireless signal processing circuit20C has structures corresponding to the wireless signal processing circuit20according to the first exemplary embodiment (seeFIG.4). That is, the wireless signal processing circuit20C is provided with a plural number of the phase control sections40and a plural number of the mixer sections50. The plural phase control sections40and plural mixer sections50are provided in respective correspondence with the reception signals SR1to SR4. Via the corresponding antenna element AN, the wireless signal processing circuit20C receives an input signal Sincombining the respective reception signals SR1to SR4transmitted from the terminals101to104. The input signal Sinis distributed to the plural mixer sections50.

The plural mixer sections50are provided in respective correspondence with the reception signals SR1to SR4and down-convert a frequency of the input signal Sincombining the respective reception signals SR1to SR4. Each mixer section50is provided with the first mixer500aand second mixer500b. The first and second mixers500aand500buse a local signal LO to down-convert the frequency of the input signal Sinin a respective RF band (or is wave band) to a baseband range or intermediate frequency band.

The plural phase control sections40are provided in respective correspondence with the plural mixer sections50. Each phase control section40alters the phase of the signal whose frequency has been down-converted by the corresponding mixer section50in accordance with an arrival direction of the corresponding reception signal.

Each phase control section40is provided with the phase rotation section400, the first phase switching section410a, the second phase switching section410b, the first variable amplifier420aand the second variable amplifier420b.

The first variable amplifier420aalters the amplitude of an output signal from the first mixer500ain accordance with the arrival direction of the corresponding reception signal. Similarly, the second variable amplifier420balters the amplitude of an output signal from the second mixer500bin accordance with the arrival direction of the corresponding reception signal. Amplitude alteration ratios (amplification factors) of the first variable amplifier420aand second variable amplifier420bare set in accordance with the weightings W provided from the controller30.

The first phase switching section410aswitches a phase rotation amount of an output signal from the first variable amplifier420aselectively in accordance with the arrival direction of the corresponding reception signal. The first phase switching section410arotates the phase of the output signal from the first variable amplifier420aby the selected rotation amount and outputs an in-phase signal of the corresponding reception signal (SR1-I to SR4-I).

The second phase switching section410bswitches a phase rotation amount of an output signal from the second variable amplifier420bselectively in accordance with the arrival direction of the corresponding reception signal. The second phase switching section410brotates the phase of the output signal from the second variable amplifier420bby the selected rotation amount and outputs a quadrature signal of the corresponding reception signal (SR1-Q to SR4-Q). The phase rotation amounts of the first phase switching section410aand second phase switching section410bare set to 0° or 180° in accordance with the weightings W provided from the controller30.

The phase rotation section400generates an in-phase signal of the corresponding reception signal by rotating the phase of the quadrature signal (SR1-Q to SR4-Q) that is the output signal of the second phase switching section410bby 90°. The output signal of the first phase switching section410ais combined with the output signal of the phase rotation section400. Thus, the reception signals SR1to SR4are separately extracted.

Thus, flows of signals in the wireless signal processing circuit20C are the opposite of flows of signals in the wireless signal processing circuit20according to the first exemplary embodiment, and the sequence of processing is reversed. According to the wireless signal processing circuit20C according to the present exemplary embodiment, similarly to the wireless signal processing circuit20according to the first exemplary embodiment, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed. Local terminals at which the local signal LO is fed into the first and second mixers500aand500bare common (connected together), and RF terminals at which the input signal Sinthat is an RF signal is fed in are common (connected together). Therefore, the mixer sections50may be constituted by, for example, multifinger transistors, and the mixer sections50may be structured very compactly.

In a modification of the example depicted inFIG.11, the first and second variable amplifiers420aand420bmay be disposed at the respective output sides of the first and second phase switching sections410aand410b.

Fifth Exemplary Embodiment

FIG.12is a diagram showing an example of structures of a wireless signal processing circuit20D according to a fifth exemplary embodiment of the disclosed technology. The wireless signal processing circuits20D are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20D features functions for forming reception beams of respective signals transmitted from the terminals101to104and receiving the reception beams.

The wireless signal processing circuit20D has structures corresponding to the wireless signal processing circuit20A according to the second exemplary embodiment (seeFIG.9). Flows of signals in the wireless signal processing circuit20D are the opposite of flows of signals in the wireless signal processing circuit20A according to the second exemplary embodiment, and the sequence of processing is reversed. The wireless signal processing circuit20D receives the input signal Sincombining the respective reception signals SR1to SR4transmitted from the terminals101to104, and separately extracts the reception signals SR1to SR4included in the input signal Sin.

According to the wireless signal processing circuit20D according to the present exemplary embodiment, similarly to the wireless signal processing circuit20A according to the second exemplary embodiment, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed, in addition to which image signals may be suppressed. Moreover, local terminals at which the first local signal LO-I is inputted to the first and second mixers500aand500bare common (connected together) and local terminals at which the second local signal LO-Q is inputted to the third and fourth mixers500cand500dare common (connected together). RF terminals at which the input signal which is an RF signal, is inputted to the first to fourth mixers500ato500dare also common (connected together). Therefore, the mixer sections may be constituted by, for example, multifinger transistors, and the mixer sections may be structured very compactly.

In a modification of the example depicted inFIG.12, the first to fourth variable amplifiers420ato420dmay be disposed at the respective output sides of the first to fourth phase switching sections410ato410d.

Sixth Exemplary Embodiment

FIG.13is a diagram showing an example of structures of a wireless signal processing circuit20E according to a sixth exemplary embodiment of the disclosed technology. The wireless signal processing circuits20E are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20E features functions for forming reception beams of respective signals transmitted from the terminals101to104and receiving the reception beams.

The wireless signal processing circuit20E has structures corresponding to the wireless signal processing circuit20B according to the third exemplary embodiment (seeFIG.10). Flows of signals in the wireless signal processing circuit20E are the opposite of flows of signals in the wireless signal processing circuit20B according to the third exemplary embodiment, and the sequence of processing is reversed. The wireless signal processing circuit20E receives the input signal Sincombining the respective reception signals SR1to SR4transmitted from the terminals101to104, and separately extracts the reception signals SR1to SR4included in the input signal Sin.

According to the wireless signal processing circuit20E according to the present exemplary embodiment, similarly to the wireless signal processing circuit20B according to the third exemplary embodiment, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed, in addition to which image signals may be suppressed.

Seventh Exemplary Embodiment

FIG.14is a diagram showing an example of structures of a wireless signal processing circuit20F according to a seventh exemplary embodiment of the disclosed technology. The wireless signal processing circuits20F are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20F features both functions for forming the transmission beams B1to B4towards the terminals101to104and transmitting the transmission signals, and functions for forming and receiving reception beams of respective signals transmitted from the terminals101to104.

The wireless signal processing circuit20F has structures corresponding to the wireless signal processing circuit20according to the first exemplary embodiment (seeFIG.4) and the wireless signal processing circuit20C according to the fourth exemplary embodiment (FIG.11). The wireless signal processing circuit20F is equipped with a plural number of the phase control sections40and the plural number of the mixer sections50. The plural phase control sections40and plural mixer sections50are provided in respective correspondence with the transmission signals ST1to ST4and with the reception signals SR1to SR4.

When the wireless signal processing circuit20F is transmitting signals, each phase control section40controls the phase of the corresponding transmission signal in accordance with the transmission direction of the transmission signal. Each mixer section50up-converts the frequency of the transmission signal whose phase has been controlled by the corresponding phase control section. The respective output signals of the plural mixer sections are combined at the combination portion60to generate an output signal Sout. The output signal Soutis radiated via the corresponding antenna element AN.

When the wireless signal processing circuit20F is receiving signals, the input signal Sincombining the respective reception signals SR1to SR4transmitted from the terminals101to104is distributed to each of the mixer sections50. Each mixer section50down-converts the frequency of the input signal Sincombining the plural reception signals SR1to SR4. Each phase control section40alters the phase of the signal whose frequency has been down-converted by the mixer section50in accordance with the arrival direction of the corresponding reception signal.

Between an input/output terminal90and the combination portion60, the wireless signal processing circuit20F includes a transmission amplifier91A, a reception amplifier91B, and switches92A and92B. The transmission amplifier91A is deployed when signals are being transmitted and increases the amplitude of the output signal Soutthat is outputted from the input/output terminal90. The reception amplifier91B is deployed when signals are being received and increases the amplitude of the input signal Sinthat is inputted at the input/output terminal90.

The switches92A and92B each have the form of a single-pole double-throw (SPDT) switch, switching between a path passing through the transmission amplifier91A and a path passing through the reception amplifier91B. Switching control of the switches92A and92B is conducted such that the path passing through the transmission amplifier91A is selected when signals are being transmitted and the path passing through the reception amplifier91B is selected when signals are being received.

In each phase control section40, the first variable amplifier420aand the second variable amplifier420bare each provided with a variable amplifier for transmission and a variable amplifier for reception, which are connected in parallel. The variable amplifier for transmission is deployed when signals are being transmitted and the variable amplifier for reception is deployed when signals are being received.

According to the wireless signal processing circuit20F according to the present exemplary embodiment, the mixer sections50and phase control sections40are used for both transmitting signals and receiving signals. Therefore, circuit size (areas occupied by circuitry) may be made smaller than in a structure in which the mixer sections50and phase control sections40are constituted separately for transmission and for reception. Local terminals at which the local signal LO is inputted into the mixers constituting the plural mixer sections are common (connected together), and RF terminals at which RF signals are inputted or outputted are common (connected together). Therefore, the mixer sections50may be constituted by, for example, multifinger transistors, and the mixer sections50may be structured very compactly. The first and second variable amplifiers420aand420bmay be disposed at either of the respective input sides or output sides of the first and second phase switching sections410aand410b.

Eighth Exemplary Embodiment

FIG.15Ais a diagram showing an example of structures of a wireless signal processing circuit20G according to an eighth exemplary embodiment of the disclosed technology. The wireless signal processing circuits20G are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20G features both functions for forming the transmission beams B1to B4towards the terminals101to104and transmitting the transmission signals, and functions for forming and receiving reception beams of respective signals transmitted from the terminals101to104. The wireless signal processing circuit20G has structures corresponding to the wireless signal processing circuit20A according to the second exemplary embodiment (seeFIG.9) and the wireless signal processing circuit20D according to the fifth exemplary embodiment (FIG.12).

In the wireless signal processing circuit20G, a plural number of phase switching sections410correspond with, for example, the transmission signal ST1. These phase switching sections410are provided on each of plural paths along which the in-phase signal ST1-I, which is in phase with the transmission signal ST1, is distributed and on each of plural paths along which the quadrature signal ST1-Q, whose phase is rotated by 90° from the transmission signal ST1, is distributed. In the wireless signal processing circuit20G, the number of paths along which the in-please signal ST1-I is distributed is two and the number of paths along which the quadrature signal ST1-Q is distributed is two. That is, the number of the phase switching sections410corresponding with the transmission signal ST1in the wireless signal processing circuit20G is four. Each phase switching section410may input/output single-ended signals. Each phase switching section410corresponding with the transmission signal ST1. selectively switches a phase rotation amount of the in-phase signal ST1-I or quadrature signal ST1-Q that is distributed along the corresponding path in accordance with a transmission direction of the transmission signal ST1, and rotates the phase of that signal. Plural numbers of the phase switching sections corresponding with the transmission signals ST2to ST4are similar.

In the wireless signal processing circuit20G, a plural number of variable amplifiers420correspond with, for example, the transmission signal ST1. These variable amplifiers420are provided in respective correspondence with the plural phase switching sections410corresponding with the transmission signal ST1, and alter the amplitudes of input signals or output signals of the corresponding phase switching sections in accordance with the transmission direction of the transmission sural ST1. The number of the variable amplifiers420corresponding with the transmission signal ST1in the wireless signal processing circuit20G is four for signal transmission and is four for signal reception. Each variable amplifier420may input/output single-ended signals.FIG.15Ashows as an example a structure in which the plural variable amplifiers420are provided between the corresponding phase switching sections410and mixers, but the arrangement of the variable amplifiers420and phase switching sections410may be the reverse. Plural numbers of the variable amplifiers corresponding with the transmission signals ST2to ST4are similar.

In the wireless signal processing circuit20G, a plural number of the mixers correspond with, for example, the transmission signal ST1. These mixers are provided in respective correspondence with the plural phase switching sections410corresponding with the transmission signal ST1and the plural variable amplifiers420corresponding with the transmission signal ST1. Each mixer up-converts the frequency of a signal that has been processed by the corresponding phase switching section410and variable amplifier420. In the wireless signal processing circuit20G, the phase switching sections410, the variable amplifiers420and the mixers correspond 1:1:1. Therefore, the number of mixers corresponding to the transmission signal ST1is four.

More specifically, the wireless signal processing circuit20G is provided with the following mixers as the plural mixers corresponding with the transmission signal ST1. The wireless signal processing circuit20G is provided with the mixer500athat uses a first local signal LO-I to up-convert the frequency of the in-phase signal ST1-I that has been processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20G also includes the mixer500bthat uses the first local signal LO-I to up-convert the frequency of the quadrature signal ST1-Q that has been processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20G is further provided with the mixer500cthat uses a second local signal LO-Q, whose phase is rotated by 90° relative to the first local signal LO-I, to up-convert the frequency of the in-phase signal ST1-I that has been processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20G is also provided with the mixer500dthat uses the second local signal LO-Q to up-convert the frequency of the quadrature signal ST1-Q that has been processed by the corresponding phase switching section410and variable amplifier420. Plural numbers of the mixers corresponding with the transmission signals ST2to ST4are similar. The signals that have been up-converted by the mixers500a,500b,500cand500dare combined with the output signals of the plural mixers corresponding with the transmission signals ST2to ST4and are outputted as the output signal Sout.

The wireless signal processing circuit20G also features functions for receiving signals. When the wireless signal processing circuit20G receives a signal, each of the plural mixers down-converts the frequency of the input signal Sincombining the plural reception signals SR1to SR4. Each of a plural number of the phase switching sections410corresponding with, for example, a reception signal SR1selectively switches a phase rotation amount of the signal whose frequency has been down-converted by the corresponding mixer in accordance with the arrival direction of the reception signal SR1, and rotates the phase of that signal. Each of a plural number of the variable amplifiers420for signal reception corresponding with the reception signal SR1alters the amplitude of an input signal or output signal of the corresponding phase switching section410in accordance with the arrival direction of the reception signal SR1.

According to the wireless signal processing circuit20G according to the present exemplary embodiment, the mixer sections and phase control sections are used for both transmitting signals and receiving signals. Therefore, circuit size (areas occupied by circuitry) may be made smaller than in a structure in which the mixer sections and phase control sections are constituted separately for transmission and for reception. In addition, according to the wireless signal processing circuit20G, image signals may be suppressed. Local terminals at which the first local signal LO-I is inputted to the first and second mixers500aand500bare common (connected together) and local terminals at which the second local signal LO-Q is inputted to the third and fourth mixers500cand500dare common (connected together). RF terminals at which an RF signals are inputted to the mixers500ato500dare also common (connected together).

FIG.15Bis a diagram illustrating a structure in which each mixer of the wireless signal processing circuit20G depicted inFIG.15Ais constituted by a transistor. The mixer constituted by the transistor500is a mixer for both transmission and reception. Bias circuits, matching circuits and the like are not depicted inFIG.15B. This kind of mixer is referred to as a resistive mixer (or a switching mixer). A local signal is inputted at the gate of the transistor500. The drain (or source) of the transistor500is an RF terminal that outputs art RF signal. The source (or drain) of the transistor500is intermediate frequency (IF) terminal that inputs an output signal from the variable amplifier420. The drain and source of the transistor500are specified to be at the same DC potential, which is the reason this mixer is referred to as a resistive mixer. The gates at which the fast local signal LO-I is inputted are common (connected together), and the gates at which the second local signal LO-Q is inputted are common (connected together). The drains at which the RF signals are outputted are common (connected together). The sources that are the IF terminals are separate. With regard to layout, in a single transistor layout with eight (or a multiple of eight) gate fingers, only the sources are structured to be separate. The eight gate fingers may be treated as a single circuit block and the layout may be made very compact.

Ninth Exemplary Embodiment

FIG.16is a diagram showing an example of structures of a wireless signal processing circuit20H_1according to a ninth exemplary embodiment of the disclosed technology. To facilitate understanding of the structures of the wireless signal processing circuit20H_1,FIG.17is a diagram showing only structural portions of the wireless signal processing circuit20H_1that relate to one (IF1) of signals (IF1to IF4) in a baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20H_1.FIG.18is a table showing examples of operations of the wireless signal processing circuit20H_1. The signals RF-P, RF-I and RF inFIG.16toFIG.18correspond to the output signal Soutor input signal Sinmentioned above. The signals IF1-I to IF4-I, IF1-Q to IF4-Q and IF correspond to the transmission signals ST1to ST4and the reception signals SR1to SR4mentioned above.

The wireless signal processing circuits20H_1are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20H_1according to the present exemplary embodiment features both functions for forming the transmission beams B1to B4towards the terminals101to104and transmitting the transmission signals, and functions for forming and receiving reception beams of respective signals transmitted from the terminals101to104.

The wireless signal processing circuit20H_1has a single balanced structure that inputs respective differentials between two local signals whose phases are orthogonal to one another, inputs/outputs differential signals in the RF band, and inputs/outputs single-ended signals in the baseband range or intermediate frequency band. The normal phase signal LO-I-P of the first local signal LO-I has a phase difference relative to the reference phase of 0°, and the antiphase signal LO-I-M of the first local signal LO-I has a phase difference relative to the reference phase of 180°. The normal phase signal LO-Q-P of the second local signal LO-Q has a phase difference relative to the reference phase of 90°, and the antiphase signal LO-Q-M of the second local signal LO-Q has a phase difference relative to the reference phase of −90°. A normal phase signal RF-P and antiphase signal RF-M in the RF band are outputted at times of transmission and inputted at times of reception. Normal phase signals IF1-I to IF4-I and quadrature signals IF1-Q to IF4-Q in the baseband range or intermediate frequency band are single-ended signals that are inputted at times of transmission and single-ended signals that are outputted at times of reception.

According to the wireless signal processing circuit20H_1, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed, in addition to which image signals may be suppressed. Because the local signal inputted to each mixer section50is a differential input, resistance against external common mode (in-phase mode) noise is improved, and leakage of the local signals at the RF terminals may be suppressed. The first to fourth variable amplifiers420ato420dmay be disposed at either of the input sides or output sides of the first to fourth phase switching sections410ato410d.

In the wireless signal processing circuit20H_1, the local terminals of the mixers that input the local signal LO-I-P are common (connected together), and the local terminals of the mixers that input the local signal LO-I-M are common (connected together). The local terminals of the mixers that input the local signal LO-Q-P are common (connected together), and the local terminals of the mixers that input the local signal LO-Q-M are common (connected together). RF terminals of the mixers that input/output the RF signal RF-P are common (connected together), and RF terminals of the mixers that input/output the RF signal RF-M are common (connected together). Therefore, the mixer sections may be constituted by, for example, multifinger transistors, and the mixer sections may be structured very compactly.

The operation table depicted inFIG.18is a description focusing on one IF signal, describing examples (U1, U2, U3and U4) of four phase states (one for each of four quadrants) and describing switching setting examples of the phase switching sections. A situation is illustrated in which the amplification factors of two variable amplifiers that amplify orthogonal signals are the same. The contents of the operation table ofFIG.18are described below in a sequence represented by sequence numbers <1> to <17>.

<1> Corresponds to four (one for each quadrant: +45°, +135°, −45°, −135°) RF signal output phase states (during transmission); corresponds to IF signal output phase states during reception

<2> Identifier symbols of unit (individual) mixers

<3> Input phases of local signal (LO signal) at unit mixers

<5> Phase inversion states of LO (1=non-inverted, −1=inverted); because this exemplary embodiment is an example in which the LO signal is not switched in quadrants, non-inverted only

<6> Input phases of IF signals at unit mixers (during transmission) or output phases of IF signals at unit mixers (during reception)

<8> Phase inversion states of IF signals (0/π switching at phase switching sections: 1=non-inverted, −1=inverted)

<9> Phase inversion switching groups of IF signals (grouping at a time of quadrant switching (two groups); collective phase switching of each group)

<10> Phases of upper side sidebands of RF signals (positions at RF terminals of unit mixers)

<11> Phases of lower side sidebands of RF signals (positions at RF terminals of unit mixers)

<13> Phases of leakage LO signals (positions at RF terminals of unit mixers)

<16> Amplitude of RF lower side sideband (during transmission: 1=signal output, 0=no signal output (image rejection); during reception: 1=signal received, 0=no signal received (image rejection)); image rejection of the lower side sideband is specified in the example described in the operation table of this exemplary embodiment
<17> LO signal leakage at RF terminal (0=LO signals through RF combination (distribution) are cancelled, 1=LO signals are not cancelled); a configuration in which LO signals are cancelled is formed in this exemplary embodiment

A method of selecting the upper side sideband and lower side sideband for image rejection is implemented with reference to the grouping of sequence <4> or sequence <7>.

<4> RF sideband groups from LO signal inversion (divided into group g and group h)

<7> RF sideband groups from a signal inversion (divided into group e and group f)

The LO signal phase is inverted for group h (or group g), or the IF signal phase is inverted (again) for group f (or group e). For example, with IF signal phase inversion, a different sideband is rejected when the IF signals of all of group f are inverted in addition to phase inversion (or non-inversion) of the IF signals at the unit mixers of group e.

FIG.19is a diagram showing an example of structures of a wireless signal processing circuit20H_2that is a modification of the wireless signal processing circuit20H_1depicted inFIG.16. To facilitate understanding of the structures of the wireless signal processing circuit20H_2,FIG.20is a diagram showing only structural portions of the wireless signal processing circuit20H_2that relate to one (IF1) of the signals (IF1to IF4) the baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20H_2. InFIG.19andFIG.20, the signals RF-P and RF-I correspond to the output signal Soutor input signal Sinmentioned above. The signals IF1-I to IF4-I and IF1-Q to IF4-Q correspond to the transmission signals ST1to ST4or reception signals SR1to SR4mentioned above. In the wireless signal processing circuit20H_2, arrangements of the variable amplifiers420differ from the wireless signal processing circuit20H_1.

In the wireless signal processing circuit20H_2, a plural number of the phase switching sections410correspond with, for example, the signal IF1. These phase switching sections410are provided on each of plural paths along which the in-phase signal IF1-I, which is in phase with the signal IF1, is distributed and on each of plural paths along which the quadrature signal IF1-Q, whose phase is rotated by 90° relative to the signal IF1, is distributed. In the wireless signal processing circuit20H_2, the number of paths along which the in-phase signal IF1-I is distributed is four and the number of paths along which the quadrature signal IF1-Q is distributed is four. That is, the number of the phase switching sections410corresponding with the signal IF1in the wireless signal processing circuit20H_2is eight. Each phase switching section410may input/output single-ended signals. Each phase switching section410corresponding with the signal IF1selectively switches a phase rotation amount of the in-phase signal IF1-I or quadrature signal IF1-Q that is distributed along the corresponding path in accordance with a transmission direction of the signal IF1, and rotates the phase of that signal. Plural numbers of the phase switching sections corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20H_2, a plural number of the variable amplifiers420correspond with, for example, the signal IF1. These variable amplifiers420are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1, and alter the amplitudes of input signals or output signals of the corresponding phase switching sections in accordance with the transmission direction of the signal IF1. The number of the variable amplifiers420corresponding with the signal IF1in the wireless signal processing circuit20H_2is eight for signal transmission and is eight for signal reception. Each variable amplifier420may input/output single-ended signals.FIG.19andFIG.20show as an example a structure in which the plural variable amplifiers420are provided between the corresponding phase switching sections410and the mixers, but the arrangement of the variable amplifiers420and phase switching sections410may be the reverse. Plural numbers of the variable amplifiers corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20H_2, a plural number of the mixers correspond with, for example, the signal IF1. These mixers are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1and the plural variable amplifiers420corresponding with the signal IF1. Each mixer up-converts the frequency of the signal that has been processed by the corresponding phase switching section410and variable amplifier420. In the wireless signal processing circuit20H_2, the phase switching sections410, the variable amplifiers420and the mixers correspond 1:1:1. Therefore, the number of mixers corresponding with the signal IF1is eight.

More specifically, the wireless signal processing circuit20H_2is provided with the following mixers as the plural mixers corresponding with the signal IF1. The wireless signal processing circuit20H_2is provided with the mixer500athat uses the normal phase signal LO-I-P of the first local signal, which is a differential signal, to up-convert the frequency of the in-phase signal IF1-I processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500cthat uses the antiphase signal LO-I-M of the first local signal to up-convert the in-phase signal IF1-I processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20H_2is further provided with the mixer500bthat uses the normal phase signal LO-I-P of the first local signal to up-convert the frequency of the quadrature signal IF1-Q processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500dthat uses the antiphase signal LO-I-M of the first local signal to up-convert the quadrature signal IF1-Q processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20H_2is provided with a mixer500ethat uses the normal phase signal LO-Q-P of the second local signal, which is a differential signal whose phase is rotated 90° relative to the first local signal, to up-convert the frequency of the in-phase signal IF1-I processed by the corresponding phase switching section410and variable amplifier420, and is provided with a mixer500gthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the in-phase signal IF1-I processed by the corresponding phase switching section410and variable amplifier420. The wireless signal processing circuit20H_2is provided with a mixer500fthat uses the normal phase signal LO-Q-P of the second local signal to up-convert the frequency of the quadrature signal IF1-Q processed by the corresponding phase switching section410and variable amplifier420, and is provided with a mixer500hthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the quadrature signal IF1-Q processed by the corresponding phase switching section410and variable amplifier420. Plural numbers of the mixers corresponding with the signals IF2to IF4are similar. The signals that have been up-converted by the mixers500a,500b,500cand500dare combined with the output signals of plural mixers corresponding with the signals IF2to IF4and are outputted as the normal phase signal RF-P of the RF signal, which is a differential signal. The signals that have been up-converted by the mixers500e,500f,500gand500hare combined with the output signals of plural mixers corresponding with the signals IF2to IF4and are outputted as an antiphase signal RF-M of the RF signal that is the differential signal.

The wireless signal processing circuit20H_2also features functions for receiving signals. When the wireless signal processing circuit20H_2receives a signal, each of the plural mixers down-converts the frequency of the input signal combining plural reception signals. Each of a plural number of the phase switching sections410corresponding with, for example, the signal IF1selectively switches a phase rotation amount of the signal whose frequency has been down-converted by the corresponding mixer in accordance with the arrival direction of the corresponding reception signal, and rotates the phase of that signal. Each of a plural number of the variable amplifiers420fur signal reception corresponding with the signal IF1alters the amplitude of an input signal or output signal of the corresponding phase switching section410in accordance with the arrival direction of the corresponding reception signal.

Tenth Exemplary Embodiment

FIG.21is a diagram showing an example of structures of a wireless signal processing circuit20I_1according to a tenth exemplary embodiment of the disclosed technology. To facilitate understanding of the structures of the wireless signal processing circuit20I_1,FIG.22is a diagram showing only structural portions of the wireless signal processing circuit20I_1that relate to one (IF1) of the signals (IF1to IF4) in the baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20I_1.FIG.23is a table showing examples of operations of the wireless signal processing circuit20I_1. An RF signal RF inFIG.21toFIG.23corresponds to the output signal Soutor input signal Sinmentioned above. The signals IF1-I to IF4-I, IF1-Q to IF4-Q and IF correspond to the transmission signals ST1to ST4and the reception signals SR1to SR4mentioned above.

The wireless signal processing circuits20I_1are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20I_1according to the present exemplary embodiment features both functions for forming the transmission beams B1to B4towards the terminals101to104and transmitting the transmission signals, and functions for forming and receiving reception beams of respective signals transmitted from the terminals101to104.

The wireless signal processing circuit20I_1has a single balanced structure that inputs respective differentials between two local signals whose phases are orthogonal to one another, inputs/outputs single-ended signals in the RF band, and inputs/outputs differential signals in the baseband range or intermediate frequency band. The normal phase signal LO-I-P of the first local signal LO-I has a phase difference relative to a reference phase of 0°, and the antiphase signal LO-I-M of the first local signal LO-I has a phase difference relative to the reference phase of 180°. The normal phase signal LO-Q-P of the second local signal LO-Q has a phase difference relative to the reference phase of 90°, and an antiphase signal LO-Q-M of the second local signal LO-Q has a phase difference relative to the reference phase of −90°. The signal RF in the RF band is outputted as a single-ended signal at times of transmission and inputted as a single-ended signal at times of reception. The normal phase signals IF1-I to IF4-I and quadrature signals IF1-Q to IF4-Q in the baseband range or intermediate frequency band are inputted as differential signals at times of transmission and outputted as differential signals at times of reception.

According to the wireless signal processing circuit20I_1, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed, in addition to which image signals may be suppressed. Because the local signal inputted to each mixer section50is a differential input, resistance against external common mode (in-phase mode) noise is improved, and leakage of the local signals at the RF terminals may be suppressed.

In the wireless signal processing circuit20I_1, the local terminals of the mixers that input the local signal LO-I-P are common (connected together), and the local terminals of the mixers that input the local signal LO-I-M are common (connected together). The local terminals of the mixers that input the local signal, LO-Q-P are common (connected together), and the local terminals of the mixers that input the local sural LO-Q-M are common (connected together). RF terminals of the mixers that input/output the RF signal are common (connected together). Therefore, the mixer sections may be constituted by, for example, multifinger transistors, and the mixer sections may be structured very compactly.

FIG.24is a diagram showing an example of structures of a wireless signal processing circuit20I_2that is a modification of the wireless signal processing circuit20I_1depicted inFIG.21. To facilitate understanding of the structures of the wireless signal processing circuit20I_2,FIG.25is a diagram showing only structural portions of the wireless signal processing circuit20I_2that relate to one (IF1) of the signals (IF1to IF4) in the baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20I_2. InFIG.24andFIG.25, the signals RF-P and RF-I correspond to the output signal Soutor input signal Sinmentioned above. I The signals IF1-I to IF4-1and IF1-Q IF4-Q correspond to the transmission signals ST1to ST4or reception signals SR1to SR4mentioned above. In the wireless signal processing circuit20I_2, arrangements of the variable amplifiers420differ from the wireless signal processing circuit20I_1.

In the wireless signal processing circuit20I_2, a plural number of the phase switching sections410correspond with, for example, the signal IF1. These phase switching sections410are provided on each of plural paths along which the in-phase signal IF1-I that is in phase with the signal IF1is distributed and on each of plural paths along which the quadrature signal IF1-Q whose phase is rotated 90° relative to the signal IF1is distributed. In the wireless signal processing circuit20I_2, the number of paths along which the in-phase signal IF1-I is distributed is two, and the number of paths along which the quadrature signal IF1-Q is distributed is two. That is, the number of the phase switching sections410corresponding with the signal IF1in the wireless signal processing circuit20I_2is four. Each phase switching section410may input/output differential signals. Each phase switching section410corresponding with the signal IF1selectively switches a phase rotation amount of the in-phase signal IF1-I or quadrature signal IF1-Q that is distributed along the corresponding path in accordance with a transmission direction of the signal IF1, and rotates the phase of that signal. Plural numbers of the phase switching sections corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20I_2, a plural number of the variable amplifiers420correspond with, for example, the signal IF1. These variable amplifiers420are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1, and alter the amplitudes of input signals or output signals of the corresponding phase switching sections410in accordance with the transmission direction of the signal IF1. The number of the variable amplifiers420corresponding with the signal IF1in the wireless signal processing circuit20I_2is four for signal transmission and is four for signal reception. Each variable amplifier420may input/output differential signals.FIG.24and.FIG.25show as an example a structure in which the plural variable amplifiers420are provided between the corresponding phase switching sections410and the mixers, but the arrangement of the variable amplifiers420and phase switching sections410may be the reverse. Plural numbers of the variable amplifiers corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20I_2, a plural number of the mixers correspond with, for example, the signal IF1. These mixers are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1and the plural variable amplifiers420corresponding with the signal IF1. Each mixer up-converts the frequency of the signal that has been processed by the corresponding phase switching section410and variable amplifier420. In the wireless signal processing circuit20I_2, the phase switching sections410, the variable amplifiers420and the mixers correspond 1:1:2. Therefore, the number of mixers corresponding with the signal IF1is eight.

More specifically, the wireless signal processing circuit20I_2is provided with the following mixers as the plural mixers corresponding with the signal IF1. The wireless signal processing circuit20I_2is provided with the mixer500athat uses the normal phase signal LO-I-P of the first local signal, which is a differential signal, to up-convert the frequency of a normal phase signal IF1-I-P of the in-phase signal, which is a :differential signal processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500gthat uses the antiphase signal LO-Q-M of the second local signal, which is a differential signal whose phase is rotated 90° relative to the first local signal, to up-convert the normal phase signal IF1-I-P. The wireless signal processing circuit20I_2is further provided with the mixer500cthat uses the antiphase signal LO-I-M of the first local signal to up-convert the frequency of an antiphase signal IF1-I-M of the in-phase signal processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500ethat uses the normal phase signal LO-Q-P of the second local signal to up-convert the antiphase signal IF1-I-M. The wireless signal processing circuit20I_2is provided with the mixer500bthat uses the normal phase signal LO-I-P of the first local signal to up-convert the frequency of a normal phase signal IF1-Q-P of the quadrature signal, which is a differential signal processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500fthat uses the normal phase signal LO-Q-P of the second local signal to up-convert the normal phase signal IF1-Q-P. The wireless signal processing circuit20I_2is provided with the mixer500dthat uses the antiphase signal LO-I-M of the first local signal to up-convert the frequency of an antiphase signal IF1-Q-M of the quadrature signal processed by the corresponding phase switching section410and variable amplifier420, and is provided with the mixer500hthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the antiphase signal IF1-Q-M. Plural numbers of the mixers corresponding with the signals IF2to IF4are similar. The signals that have been up-converted by the mixers500ato500hare combined with the output signals of the plural mixers corresponding with the signals IF2to IF4and are outputted as the RF signal.

The wireless signal processing circuit20I_2also features functions for receiving signals. When the wireless signal processing circuit20I_2receives a signal, each of the plural mixers down-converts the frequency of the input signal combining plural reception signals. Each of a plural number of the phase switching sections410corresponding with, for example, the signal IF1selectively switches a phase rotation amount of the signal whose frequency has been down-converted by the corresponding mixer in accordance with the arrival direction of the corresponding reception signal, and rotates the phase of that signal. Each of a plural number of the variable amplifiers420for signal reception corresponding with the signal IF1alters the amplitude of an input signal or output signal of the corresponding phase switching section410in accordance with the arrival direction of the corresponding reception signal.

Eleventh Exemplary Embodiment

FIG.26is a diagram showing an example of structures of a wireless signal processing circuit20J_1according to an eleventh exemplary embodiment of the disclosed technology. To facilitate understanding of the structures of the wireless signal processing circuit20J_1,FIG.27is a diagram showing only structural portions of the wireless signal processing circuit20J_1that relate to one (IF1) of the signals (IF1to IF4) in the baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20J_1.FIG.28is a table showing examples of operations of the wireless signal processing circuit20J_1. RF signals RF inFIG.26toFIG.28correspond to the output signal Soutor input signal Sinmentioned above. The signals IF1-I to IF4-I, IF1-Q to IF4-Q and IF correspond to the transmission signals ST1to ST4and the reception signals SR1to SR4mentioned above.

The wireless signal processing circuits20J_1are provided in respective correspondence with the plural antenna elements AN. Each wireless signal processing circuit20J_1features both functions for forming the transmission beams B1to B4towards the terminals101to104and transmitting the transmission signals, and functions for forming and receiving reception beams of respective signals transmitted from the terminals101to104.

The wireless signal processing circuit20J_1has a single balanced structure that inputs respective differentials between two local signals whose phases are orthogonal to one another, inputs/outputs differential signals in the RF band, and inputs/outputs differential signals in the baseband range or intermediate frequency band. The normal phase signal LO-I-P of the first local signal LO-I has a phase difference relative to the reference phase of 0°, and the antiphase signal LO-I-M of the first local signal LO-I has a phase difference relative to the reference phase of 180°. The normal phase signal LO-Q-P of the second local signal LO-Q has a phase difference relative to the reference phase of 90°, and the antiphase signal LO-Q-M of the second local signal LO-Q has a phase difference relative to the reference phase of −90°. A normal phase signal RF-P and antiphase signal RF-M in the RF band are outputted at times of transmission and inputted at times of reception. The normal phase signals IF1-I to IF4-I and quadrature signals IF1-Q to IF4-Q in the baseband range or intermediate frequency band are inputted as differential signals at times of transmission and outputted as differential signals at times of reception.

According to the wireless signal processing circuit20J_1, signal losses may be suppressed while an increase in circuit size (areas occupied by circuitry) is suppressed, in addition to which image signals may be suppressed. Because the local signal inputted to each mixer section50is a differential input, resistance against external common mode (in-phase mode) noise is improved, and leakage of the local signals at the RF terminals may be suppressed.

In the wireless signal processing circuit20J_1, the local terminals of the mixers that input the local signal LO-I-P are common (connected together), and the local terminals of the mixers that input the local signal LO-I-M are common (connected together). The local terminals of the mixers that input the local signal LO-Q-P are common (connected together), and the local terminals of the mixers that input the local signal LO-Q-M are common (connected together). RF terminals of the mixers that input/output the RF signal RF-P are common (connected together), and RF terminals of the mixers that input/output the RF signal RF-M are common (connected together). Therefore, the mixer sections may be constituted by, for example, multifinger transistors, and the mixer sections may be structured very compactly.

As depicted inFIG.29, the wireless signal processing circuit20J_1may be formed with a structure in which two mixers share each phase switching section. As a result, the effect of suppressing an increase in circuit size (areas occupied by circuitry) is strengthened.

FIG.30is a diagram showing an example of structures of a wireless signal processing circuit20J_2that is a modification of the wireless signal processing circuit20J_1depicted inFIG.26andFIG.27. To facilitate understanding of the structures,FIG.30is a diagram showing only structural portions of the wireless signal processing circuit20J_2that relate to one (IF1) of the signals (IF1to IF4) in the baseband range or intermediate frequency band that are processed in the wireless signal processing circuit20J_2. InFIG.30, the signals RF-P and RF-I correspond to the output signal Soutor input signal Sinmentioned above. The signals IF1-I to IF4-I and IF1-Q to IF4-Q correspond to the transmission signals ST1to ST4or reception signals SR1to SR4mentioned above. In the wireless signal processing circuit20J_2, arrangements of the variable amplifiers420differ from the wireless signal processing circuit20J_1.

In the wireless signal processing circuit20J_2, a plural number of the phase switching sections410correspond with, for example, the signal IF1. These phase switching sections410are provided on each of plural paths along which the in-phase signal IF1-I that is in phase with the signal IF1is distributed and on each of plural paths along which the quadrature signal IF1-Q whose phase is rotated 90° relative to the signal IF1is distributed. In the wireless signal processing circuit20J_2, the number of paths along which the in-phase signal IF1-I is distributed is four and the number of paths along which the quadrature signal IF1-Q is distributed is four. That is, the number of the phase switching sections410corresponding with the signal IF1in the wireless signal processing circuit20J_2is eight. Each phase switching section410may input/output differential signals. Each phase switching section410corresponding with the signal IF1selectively switches a phase rotation amount of the in-phase signal or quadrature signal IF1-Q that is distributed along the corresponding path in accordance with a transmission direction of the signal IF1, and rotates the phase of that signal. Plural numbers of the phase switching sections corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20J_2, a plural number of the variable amplifiers420correspond with, for example, the signal IF1. These variable amplifiers420are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1, and alter the amplitudes of input signals or output signals of the corresponding phase switching sections in accordance with the transmission direction of the signal IF1. The number of the variable amplifiers420corresponding with the signal IF1in the wireless signal processing circuit20J_2is eight for signal transmission and is eight for signal reception. Each variable amplifier420may input/output differential signals.FIG.30shows as an example a structure in which the plural variable amplifiers420are provided between the corresponding phase switching sections410and mixers, but the arrangement of the variable amplifiers420and phase switching sections410may be the reverse. Plural numbers of the variable amplifiers420corresponding with the transmission signals IF2to IF4are similar.

In the wireless signal processing circuit20J_2, a plural number of the mixers correspond with, for example, the signal IF1. These mixers are provided in respective correspondence with the plural phase switching sections410corresponding with the signal IF1and the plural variable amplifiers420corresponding with the signal IF1. Each mixer up-converts the frequency of the signal that has been processed by the corresponding phase switching section410and variable amplifier420. In the wireless signal processing circuit20J_2, the phase switching sections410, the variable amplifiers420and the mixers correspond 1:1:2. Therefore, the number of mixers corresponding with the signal IF1is 16.

More specifically, the wireless Signal processing circuit20J_2is provided With the following mixers as the plural mixers corresponding with the signal IF1. The wireless signal processing circuit20J_2is provided with the mixer500athat uses the normal phase signal LO-I-P of the first local signal, which is a differential signal, to up-convert the frequency of the normal phase signal IF1-I-P of the in-phase signal, which is a differential signal processed by the corresponding phase switching section410and variable amplifier420, is provided with the mixer500ethat uses the antiphase signal LO-I-M of the first local signal to up-convert the normal phase signal IF1-I-P, is provided with a mixer500ithat uses the normal phase signal LO-Q-P of the second local signal, which is a differential signal whose phase is rotated 90° relative to the first local signal, to up-convert the normal phase signal IF1-I-P, and is provided with a mixer500mthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the normal phase signal IF1-I-P. The wireless signal processing circuit20J_2is further provided with the mixer500bthat uses the normal phase signal LO-I-P of the first local signal to up-convert the frequency of the antiphase signal IF1-I-M of the in-phase signal processed by the corresponding phase switching section410and variable amplifier420, is provided with the mixer500fthat uses the antiphase signal LO-I-M of the first local signal to up-convert the antiphase signal IF1-I-M, is provided with a mixer500jthat uses the normal phase signal LO-Q-P of the second local signal to up-convert the antiphase signal IF1-I-M, and is provided with a mixer500nthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the antiphase signal IF1-I-M. The wireless signal processing circuit20J_2is provided with the mixer500cthat uses the normal phase signal LO-I-P of the first local signal to up-convert the frequency of the normal phase signal IF1-Q-P of the quadrature signal, which is a differential signal processed by the corresponding phase switching section410and variable amplifier420, is provided with the mixer500gthat uses the antiphase signal LO-I-M of the first local signal to up-convert the normal phase signal IF1-Q-P, is provided with a mixer500kthat uses the normal phase signal LO-Q-P of the second local signal to up-convert the normal phase signal IF1-Q-P, and is provided with a mixer500othat uses the antiphase signal LO-Q-M of the second local signal to up-convert the normal phase signal IF1-Q-P. The wireless signal processing circuit20J_2is provided with the mixer500dthat uses the normal phase signal LO-I-P of the first local signal to up-convert the frequency of the antiphase signal IF1-Q-M of the quadrature signal processed by the corresponding phase switching section410and variable amplifier420, is provided with the mixer500hthat uses the antiphase signal LO-I-M of the first local signal to up-convert the antiphase signal IF1-Q-M, is provided with a mixer500lthat uses the normal phase signal LO-Q-P of the second local signal to up-convert the antiphase signal IF1-Q-M, and is provided with a mixer500pthat uses the antiphase signal LO-Q-M of the second local signal to up-convert the antiphase signal IF1-Q-M. Plural numbers of the mixers corresponding with the signals IF2to IF4are similar. The signals that have been up-converted by the mixers500a,500c,500f,500h,500l,500i,500oand500nare combined with the output signals of plural mixers corresponding with the signals IF2to IF4and are outputted as the normal phase signal RF-P of the RF signal, which is a differential signal. The signals that have been up-converted by the mixers500b,500d,500e,500g,500k,500j,500pand500mare combined with the output signals of plural mixers corresponding with the signals IF2to IF4and are outputted as the antiphase signal RF-M of the RF signal, which is a differential signal.

The wireless signal processing circuit20J_2also features functions for receiving signals. When the wireless signal processing circuit20J_2receives a signal, each of the plural mixers down-converts the frequency of the input signal combining plural reception signals. Each of a plural number of the phase switching sections410corresponding with, for example, the signal IF1selectively switches a phase rotation amount of the signal whose frequency has been down-converted by the corresponding mixer in accordance with the arrival direction of the corresponding reception signal, and rotates the phase of that signal. Each of a plural number of the variable amplifiers420for signal reception corresponding with the signal IF1alters the amplitude of an input signal or output signal of the corresponding phase switching section410in accordance with the arrival direction of the corresponding reception signal.

As depicted inFIG.31, the wireless signal processing circuit20J_2may be formed with a structure in which two mixers share each phase switching section. As a result, the effect of suppressing an increase in circuit size (areas occupied by circuitry) is strengthened.

According to the disclosed technology, while an increase in circuit size (areas occupied by circuitry) may be suppressed, signal losses may be suppressed in a wireless device that conducts beamforming.

All cited documents, patent applications, and technical standards mentioned in the present specification are incorporated by reference in the present specification to the same extent as if each individual cited document, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.