Power combiner/distributor, power amplifying circuit, and wireless apparatus

A power combiner/distributor including first, second, and third waveguides connected with each other in a planar shape, and for either one of distributing power inputted from the first waveguide to the second and third waveguides and combining powers inputted from the second and third waveguides to input the combined power to the first waveguide is provided. The power combiner/distributor includes a branch circuit connected with the first waveguide and for branching a transmission path formed in the first waveguide into first and second transmission paths, and decoupling circuits connected with the branch circuit and also to the second and third waveguides, respectively, the decoupling circuits having a power losing resonator coupled to the second and third waveguides, resonating within an operation frequency band, and causing a power loss.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2011-228755, which was filed on Oct. 18, 2011, the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention generally relates to a power combiner/distributor to be used within a microwave band or a millimeter wave band, a power amplifying circuit and a wireless apparatus equipped with the combiner/distributor.

BACKGROUND OF THE INVENTION

For power combiners that combine a plurality of microwave powers, it is desired that powers are inputted thereto in the same phase to be able to be combined. Moreover, branch ports of such power combiners are desired to have a high isolation property from each other so as to prevent interference between circuits connected to the branch ports, respectively.

As power combiners using striplines, there exists a Wilkinson power distributor. With the Wilkinson power distributor, although it has in-phase distribution and high isolation properties, it has low power durability, causing a problem that it cannot be used with a large power.

As power combiner/distributors using waveguides, a MAGIC-T model has often been used. However, because the MAGIC-T model has a three dimensional shape, it has a complicated structure, causing difficulties in reducing in cost and size and securing the isolation between output ports.

Further, power combining and distribution can be performed by using the conventional waveguide directional couplers. However, when a signal is inputted from a first input port to be distributed to first and second output ports P2and P3, a relative phase difference between the distributed output signals is 90°; therefore, when the signals are to be used in a combining circuit, a shaft length of a waveguide for the first output port P2is required to be set longer by ¼ of a guide wavelength than that of a waveguide for the second output port P3so as to correct 90° of the phase difference. Therefore, a distribution phase variance is caused by influence of frequency properties of the wavelengths of the waveguides, causing a difficulty in obtaining satisfactory distribution properties over a wide band.

JP2592476B discloses a waveguide hybrid coupler.FIG. 17Ais a cross-sectional view of a hybrid coupler10disclosed in JP2592476B, andFIG. 17Bis a cross-sectional plan view taken along a line B-B inFIG. 17A. The hybrid coupler10is formed with a first waveguide12and a second waveguide14. Each waveguide has a rectangular cross-section part of which a ratio between the longer wall and the shorter wall is 2:1. The hybrid coupler10has two functions: a hybrid coupling function and a phase correcting function for the electromagnetic energy between the two waveguides12and14. A coupling gate24arranged in a common side wall22has a fixed length substantially the same as a wavelength of one free space of the electromagnetic energy in a longitudinal axis of either one of the waveguides12and14.

Moreover, by arranging the coupling gate24in the common side wall of the two waveguides12and14, a hybrid coupler with short slots formed orthogonal to the side wall is configured. A microwave signal coupling between the two waveguides via the gate24receives a phase shift by 90° of lag.

Thus, a necessary phase correction is performed by using a set of four capacitive irises36arranged in the first waveguide12on the side of a penetration port26from the gate24and a set of four inductive irises38arranged in the second waveguide14on the side of a coupling port28from the gate24. The capacitive irises36in the waveguide12configure a phase shifter40for causing a phase shift by 45° of lag at the penetration port26. The inductive irises38in the waveguide14configure a phase shifter42for causing a phase shift by 45° of lead at the coupling port28. The phase of the signal shifted by 45° through the phase shifter42and then by −90° through the gate24matches with the phase of the signal shifted by −45° through the phase shifter40.

The waveguide hybrid coupler disclosed in JP2592476B has a structure in which the plurality of capacitive irises are provided in one of the waveguides to project from its wider face and the plurality of inductive irises are provided in the other waveguide to project from its narrower face. Thus, the entire structure of the unit is complicated, and it has been difficult to fabricate the unit.

SUMMARY OF THE INVENTION

The present invention is made in view of the above situation, and generally aims to provide a power combiner/distributor that is reduced in size and cost by being configured in a planar shape and has a symmetric structure to be able to distribute in-phase, a power amplifying circuit and a wireless device equipped with the combiner/distributor.

The power combiner/distributor of the present invention uses, in its part, a resonator with larger loss compared to other components therein without using a terminator having a function of absorbing all the inputted radio waves, and thus, it can be configured in a planar shape even though it is a waveguide, an in-phase distribution can be performed by having a symmetric shape, and an isolation between distribution ports can be secured.

Specifically, in the waveguide circuit, a resonator with low no-load Q value and low loss is arranged between two distribution ports which the isolation is required. A further specific configuration is as follows.

(1) According to an aspect of the invention, a power combiner/distributor including first, second, and third waveguides (WG1, WG2and WG3) connected with each other in a planar shape, and for either one of distributing power inputted from the first waveguide to the second and third waveguides and combining powers inputted from the second and third waveguides to the first waveguide is provided. The power combiner/distributor includes a branch circuit (combination of R11, R12, and R13) connected with the first waveguide and for branching a transmission path formed in the first waveguide into first and second transmission paths (CC1and CC2), and decoupling circuits (R22, R33, and RL) connected (indirectly) with the branch circuit and also to the second and third waveguides, respectively, the decoupling circuits having a power losing resonator (RL=R23+Re) coupled to the second and third waveguides, resonating within an operation frequency band, and causing a power loss.

(2) The power losing resonator may include a resistor (Re) for acting on either one of an electric field and a magnetic field in the waveguide to cause the loss, or includes the resistor and a resonant cavity (R23).

(3) The first transmission path may be connected between the power losing resonator and the second waveguide and formed with at least one resonant cavity (R22) coupled to the power losing resonator and the second waveguide. The second transmission path may be connected between the power losing resonator and the third waveguide and formed with at least one resonant cavity (R33) coupled to the power losing resonator and the third waveguide.

(4) The branch circuit may be formed with a resonant cavity (R12) connected with the first transmission path and coupled to a branching resonant cavity (R11), and another resonant cavity (R13) connected with the second transmission path and coupled to the branching resonant cavity.

(5) An electromagnetic wave that propagates in the second waveguide may have the same phase as an electromagnetic wave that propagates in the third waveguide, coupling degrees of the power losing resonator with the second and third waveguides and a Q value of the power losing resonator may be determined so that an amount of the electromagnetic wave that leaks from the second waveguide to the third waveguide and an amount of the electromagnetic wave that leaks from the third waveguide to the second waveguide are −10 dB or below, respectively.

(6) According to another aspect of the invention, a power amplifying circuit is provided. The circuit includes the power combiner/distributor described as above in any one of (1) to (5), the combiner/distributor configuring either one of a power distributor for distributing an input signal to a plurality of power amplifiers and a power combiner for combining output signals from a plurality of power amplifiers.

(7) According to another aspect of the invention, a wireless apparatus is provided. The apparatus includes a circuit for distributing or combining communication signals and provided with the power combiner/distributor described as above in any one of (1) to (5).

According to the above aspects of the invention, a radio wave inputted from the first waveguide can be distributed in-phase to be outputted within a wide frequency band, and a good reflection property, an excellent low loss property, and a high isolation property can be obtained at the same time.

DETAILED DESCRIPTION

First Embodiment

A power combiner/distributor of the first embodiment is described with reference toFIGS. 1 to 10.FIG. 1is a perspective view of a main part of a power combiner/distributor101. Further,FIG. 2is a plan view of the power combiner/distributor101without an upper metal plate. Note that,FIG. 1only shows a spatial shape such as inside a waveguide. The power combiner/distributor101has a first metal plate forming the space, such as inside the waveguide, and a second metal plate covering the space by overlapping with the first metal plate.FIG. 2illustrates the first metal plate.

The power combiner/distributor101includes a first waveguide WG1, a second waveguide WG2, and a third waveguide WG3. When the first waveguide WG1is referred to as a first port, the second waveguide WG2is referred to as a second port, and a third waveguide WG3is referred to as a third port, the power combiner/distributor101either distributes a power inputted from the first port #1to the second port #2and the third port #3or combines powers inputted from the second port #2and the third port #3and outputs it to the first port #1. The waveguides WG1, WG2, and WG3are arranged on the same plane.

The power combiner/distributor101is formed with a branching resonant cavity R11coupling to a resonant cavity R12and a resonant cavity R13, and also to the first waveguide WG1. The resonant cavities R12, R13and the branch resonant cavity R11configure a branch circuit.

Moreover, the power combiner/distributor101is formed with a resonant cavity R22coupling to the second waveguide WG2and a resonant cavity R33coupling to the third waveguide WG3. The resonant cavities R12and R22are connected with each other via the waveguide WG12. Similarly, the resonant cavities R13and R33are connected with each other via the waveguide WG13. The waveguide WG12, the resonant cavity R22, and the waveguide WG2configure a first transmission path CC1, and the waveguide WG13, the resonant cavity R33, and the waveguide WG3configure a second transmission path CC2.

Further, the power combiner/distributor101is formed with a resonant cavity R23coupling to the second waveguide WG2and the third waveguide WG3, for resonating within an operation frequency band, and includes a resistor Re arranged within the resonant cavity R23. The resonant cavity R23and the resistor Re configure a power losing resonator. The resistor Re is obtained by sintering silicon carbide (SiC) particles into a cuboid shape having the same height as the resonant cavity R23. The resistor Re functions on the resonator with a relative permittivity ∈r=around12, a large tanδ value, and a small Q value obtained because of the resonant cavity R23and the resistor Re. The resistor Re is arranged at the center of the resonant cavity R23where an electric field intensity is high, and it is mainly coupled to the electric field to generate ohmic loss. The resistor Re is also coupled to a magnetic field to generate ohmic loss. Therefore, the power losing resonator attenuates the signal that is to be propagated from the second waveguide WG2to the third waveguide WG3or from the third waveguide WG3to the second waveguide WG2via the resonate cavity R23.

A waveguide iris (hereinafter, simply referred to as “the iris”) Jr is formed between the first waveguide WG1and the branching resonant cavity R11to function as a window for determining a coupling degree. Similarly, irises Jr are formed between the branching resonant cavity R11and the resonant cavity R12and between the branching resonant cavity R11and the resonant cavity R13. Moreover, irises Jr are formed between the resonant cavity R12and the waveguide WG12and between the waveguide WG12and the resonant cavity R22. Similarly, irises Ir are formed between the resonant cavity R13and the waveguide WG13and between the waveguide WG13and the resonant cavity R33. Moreover, irises Ir are formed between the resonant cavity R22and the waveguide WG12and between the resonant cavity R22and the resonant cavity R23. Similarly, irises Ir are formed between the resonant cavity R33and the waveguide WG3and between the resonant cavity R33and the resonant cavity R23. The resonant space is divided by these irises, and the coupling degrees between the adjacent resonant cavities and between each cavity and the adjacent waveguide thereto are determined by the irises, respectively.

FIG. 3is a graph illustrating frequency properties of the power combiner/distributor101. Here, S11indicates a reflection property seen from the port #1. S21indicates a passing property (distributive property) from the port #1to the port #2, and S31indicates a passing property (distributive property) from the port #1to the port #3. S32indicates a passing property (decoupling property) from the port #3to the port #2. The power combiner/distributor101is formed into a symmetric shape with respect to an electromagnetic wave propagation direction of the first waveguide WG1, and thus, S21and S31have the same property.

Thus, the signal is distributed at −3 dB over a wide band centering on the frequency of 9.75 GHz, and a high decoupling property of approximately −40 dB or below is obtained. Moreover, also for the reflection property seen from the port #1(S11), a low reflection property of −30 dB or below is obtained.

Next, the function of the power combiner/distributor101of the first embodiment is described.

First, a fundamental equivalence circuit of a power distributing circuit part of the power combiner/distributor101is illustrated inFIG. 4. In the power distributing circuit, an input terminal P1and output terminals P2and P3are connected with each other via a resonator Rj (referred to as the junction resonator here since it is used particularly for the connecting). Here, when a coupling amount between the junction resonator Rj with each of the terminals P1, P2, and P3is expressed by using external Q: Qe1, Qe2, and Qe3respectively, an input matching condition of the terminal P1is as follows.
1/Qe1=(1/Qe2)+(1/Qe3)  (1)

Next, when a power distribution ratio between the terminals P2and P3is n:1, the following relation is established between each coupling coefficient and a scattering parameter.
|S21|2/|S31|2=Qe3/Qe2=n(2)

As a result, Qe2and Qe3that give a desired distribution ratio are expressed by the following equations.
Qe2={(1+n)/n}Qe1, Qe3=(1+n)Qe1  (3)

For example, when the power distribution ratio is 4:1 and the external Q of the terminal P1is Qe1=100, the external Q becomes Qe2=125 and Qe3=500 based on Equations 3. A calculation result of the frequency property by the fundamental equivalent circuit is illustrated inFIG. 5. InFIG. 5, the lateral axis is a normalized frequency, and the normalized frequency=1 corresponds to the operation frequency.

As above, the junction resonator of 1-input/2-output functions as a power combining circuit; however, it has a narrow band. Therefore, the junction resonator is used as a part of a filter to widen the band of the filter.

FIG. 6Aillustrates an equivalent circuit of a fundamental two stage filter. The filter is branched into two at a coupling part between the resonators as illustrated inFIG. 6Bso as to widen the band.

Here, the matching condition of the terminal P1is expressed by the following equation in comparison to a designing parameter of the fundamental filter circuit.
k2=k122+k132(4)

Moreover, when the power distribution ratio between the terminals P2and P3is n:1, the following relation is established between each coupling coefficient and the scattering parameter.
|S21|2/|S312=k122/k132=n(5)
Therefore, each parameter is unambiguously obtained as follows.
k12=√{n/(n+1)}k, k13={1/√(n+1)}k(6)
Here, the external Q (Qe) is defined as follows.
Qe1=Qe2=Qe3=Qe(7)

By setting the circuit parameters as above, the input power from the terminal P1is distributed to the terminals P2and P3to be outputted therefrom.

Here, a two-way distributor based on the two stage filter of which a center frequency is 9.5 GHz, a band is 800 MHz, and a ripple is 0.1 dB is designed. The designing parameters used here are indicated by Equations 8.
k=11.6%,Qe=10.0  (8)

Based on this filter, a power distributor in which the distribution to the terminals P2and P3is 1:1 is designed. Each parameter has the following value based on Equations 6, 7, and 8.
k12=k13=8.2,Qe=10.0  (9)

Next, a branch circuit is designed by a waveguide circuit.FIG. 7is a plan view of a model of designing the branch circuit (H-plane pattern). This model is the power combiner/distributor101illustrated inFIG. 2without the resonant cavities R22and R33and the waveguides WG12and WG13. The first waveguide WG1is connected with the triangle-shaped resonant cavity R11(junction resonator). The two outputs of the resonant cavity R11are electromagnetically coupled to the resonant cavities R12and R13, respectively. Further, the resonant cavities R12and R13are connected with the waveguides WG2and WG3, respectively. Between each resonant cavity and the adjacent waveguide thereto and between the adjacent resonant cavities are connected via the irises, and each coupling amount therebetween is set to the coupling coefficient and the external Q that are given by Equation 9.

FIG. 8is a graph illustrating a frequency property of the model illustrated inFIG. 7. It can be seen that the input from the port #1is equally distributed to the ports #2and #3. Note that, the isolation between the ports #2and #3is about −6 dB at 9.5 GHz.

In order to prevent interference between machines connected with the power combiner/distributor, the power combiner/distributor requires a sufficient isolation between the ports. Therefore, here, a circuit is added to the model ofFIG. 7to secure the isolation.

FIG. 9is an equivalent circuit diagram of the power combiner/distributor101. The equivalent circuit inFIG. 9is configured with the branch circuit (part A) illustrated inFIG. 6Band a decoupling circuit (part B) for obtaining a high isolation. The decoupling circuit (B part) is based on a fundamental of a method for high isolation of a Wilkinson power distributor, of which features are described as follows.

FIG. 10is an equivalent circuit diagram of the Wilkinson power distributor. In the Wilkinson power distributor, each of the phase shifters PS2and PS3is normally configured with a transmission path with ¼ of wavelength so that the power that propagates between the terminals P2and P3via the phase shifters PS2and PS3is shifted to overlap in a reversed phase at the destination terminal (either one of the terminals PS2and PS3). However, with the power combiner/distributor101of this embodiment, three resonators (R11, R12, and R13) interpose between the ports #2and #3, and therefore, the ports #2and #3have a reversed phase relation. Therefore, the phase shifters PS2and PS3configured with, for example, the transmission lines are not required.

Moreover, the part with the resistor R in the Wilkinson power distributor inFIG. 10is difficult to manufacture with the waveguide; however, in this embodiment, it is replaced with the resonator. In other words, the power losing resonator configured by the resonant cavity R23and the resistor Re inFIGS. 1 and 2covers the function of the resistor R in the Wilkinson power distributor. This is one of the distinctive features of this embodiment.

With the Wilkinson power distributor, the parts where the resistor R interacts with a line L2and a line L3are branched into T-shape; however, if the T-shape branches are formed in the waveguide, non continuous parts will be created, causing a change in distribution ratio. Therefore, in this embodiment, the junction resonator is configured alternative to the T-shape branch. In other words, the resonant cavities R22and R33inFIGS. 1 and 2cover the function of the T-shape branches, respectively.

The power combiner/distributor101functions based on the fundamental described above, and thus, a waveguide power combiner/distributor can be obtained in which the electromagnetic waves that propagate in the second and third waveguides WG2and WG3have the same phase and the amount of the electromagnetic wave that leaks from the second waveguide WG2to the third waveguide WG3and the amount of the electromagnetic wave that leaks from the third waveguide WG3to the second waveguide WG2are −10 dB or below.

When the isolation between the ports #2and #3is −10 dB or below, it can be used as a power combiner/distributor having a practically sufficient decoupling property. The isolation can be defined by the coupling degrees of the power losing resonator with the second waveguide WG2and the third waveguide WG3and the Q value of the power losing resonator.

Second Embodiment

FIG. 11is a perspective view of a main part of a power combiner/distributor102of a second embodiment. Note that,FIG. 11only shows a spatial shape such as inside a waveguide.

The power combiner/distributor102includes a first waveguide WG1, a second waveguide WG2, and a third waveguide WG3. When the first waveguide WG1is referred to as a first port, the second waveguide WG2is referred to as a second port, and a third waveguide WG3is referred to as a third port, the power combiner/distributor102either distributes a power inputted from the first port #1to the second port #2and the third port #3or combines powers inputted from the second port #2and the third port #3and outputs it to the first port #1. The waveguides WG1, WG2, and WG3are arranged on the same plane.

The power combiner/distributor102is formed with a branching resonant cavity R11coupling to a resonant cavity R12and a resonant cavity R13, and also to the first waveguide WG1. The resonant cavities R12and R13and the branching resonant cavity R11configure a branch circuit.

A triangle section at the center of the branching resonant cavity R11is higher (thicker) than other parts. Thus, the center of the resonant space is recessed in both top and bottom surfaces. In this manner, the resonant frequency of the resonator can be increased to a predetermined frequency. In other words, generally, when a line is connected to a resonator, a resonant frequency is reduced by an inductance component of the connection part. Therefore, the plan size of the resonator is required to be reduced in advance so as to resonate at the predetermined frequency. Moreover, with the design of the circuit of this embodiment, because the band is desired to be wide and a strong bond is required between the lines, the size of the resonator is significantly reduced. However, if the plan size of the resonator is excessively small, the connection parts with the lines cannot be formed. Therefore, by increasing the height of the center of the resonator (in the section with high electric field intensity), the resonant frequency is increased and, thus, the resonator can be formed to have an appropriate plan dimension.

Moreover, the power combiner/distributor102is formed with a resonant cavity R22coupling to the second waveguide WG2and a resonant cavity R33coupling to the third waveguide WG3. The resonant cavity R22and the waveguide WG2configure a first transmission path CC1, and the resonant cavity R33and the waveguide WG3configure a second transmission path CC2.

A resistor Re is arranged in a part with an iris Ir between the resonant cavities R22and R33. The resistor Re functions as a power losing resonator as it is. Therefore, the power losing resonator attenuates a signal that is to be propagated from the second waveguide WG2to the third waveguide WG3or from the third waveguide WG3to the second waveguide WG2via the iris Ir.

FIG. 12is a graph illustrating frequency properties of the power combiner/distributor102. Here, S11indicates a reflection property seen from the port #1. S21indicates a passing property (distributive property) from the port #1to the port #2, and S31indicates a passing property (distributive property) from the port #1to the port #3. S32indicates a passing property (decoupling property) from the port #2to the port #3. The power combiner/distributor102is formed into a symmetric shape with respect to an electromagnetic wave propagation direction of the first waveguide WG1, and thus, S21and S31have the same property. Thus, it can be seen that the input from the port #1is equally distributed to the ports #2and #3. Moreover, the isolation between the ports #2and #3is −19 dB at 8.5 GHz, and a sufficient decoupling property is obtained.

Third Embodiment

FIG. 13is a perspective view of a main part of a power combiner/distributor103of a third embodiment. Note that,FIG. 13only shows a spatial shape such as inside a waveguide.

The power combiner/distributor103includes a first waveguide WG1, a second waveguide WG2, and a third waveguide WG3. When the first waveguide WG1is referred to as a first port, the second waveguide WG2is referred to as a second port, and a third waveguide WG3is referred to as a third port, the power combiner/distributor103either distributes a power inputted from the first port #1to the second port #2and the third port #3or combines powers inputted from the second port #2and the third port #3and outputs it to the first port #1. The waveguides WG1, WG2, and WG3are arranged on the same plane.

The power combiner/distributor103is formed with a branching resonant cavity R11coupling to a resonant cavity R12and a resonant cavity R13, and also to the first waveguide WG1. A resonant cavity R10is formed between the branching resonant cavity R11and the first waveguide WG1. Square sections at the centers of the branching resonant cavity R11and the resonant cavity R10are higher (thicker) than other parts, respectively. Thus, the resonant space is recessed in both top and bottom surfaces. In this manner, as described in the second embodiment, the resonator can be formed to have an appropriately large plan dimension.

Moreover, the power combiner/distributor103is formed with a resonant cavity R22coupling to the second waveguide WG2and a resonant cavity R33coupling to the third waveguide WG3. The resonant cavity R22and the waveguide WG2configure a first transmission path, and the resonant cavity R33and the waveguide WG3configure a second transmission path.

Moreover, the power combiner/distributor103is formed with a resonant cavity R23coupling to the second waveguide WG2and the third waveguide WG3, for resonating within an operation frequency band, and includes a resistor Re arranged within the resonant cavity R23. The resonant cavity R23and the resonant Re configure a power losing resonator. The power losing resonator attenuates a signal that is to be propagated from the second waveguide WG2to the third waveguide WG3or from the third waveguide WG3to the second waveguide WG2via an iris Ir.

The resonant cavity R10functions as a band passing filter, and an attenuation amount outside a selected band increases.

FIG. 14is a graph illustrating frequency properties of the power combiner/distributor103. Here, S11indicates a reflection property seen from the port #1. S21indicates a passing property (distributive property) from the port #1to the port #2, and S31indicates a passing property (distributive property) from the port #1to the port #3. S32indicates a passing property (decoupling property) from the port #2to the port #3. The power combiner/distributor103is formed into a symmetric shape with respect to an electromagnetic wave propagation direction of the waveguide WG1, and thus, S21and S31have the same property. Thus, it can be seen that the input from the port #1is equally distributed to the ports #2and #3. Moreover, the isolation between the ports #2and #3is −15 dB at 8.5 GHz, and a sufficient decoupling property is obtained.

Fourth Embodiment

FIG. 15is a circuit diagram of a high frequency power amplifying circuit200of a fourth embodiment. The high frequency power amplifying circuit200includes a plurality of amplifiers90A to90G and a plurality of power combiner/distributors100A to100F, a high frequency signal inputted from an input port IN is amplified in power to be outputted to an output port OUT.

The power combiner/distributor100A equally distributes an output signal from the amplifier90A. The amplifiers90B and90C amplify the equally distributed signal. The power combiner/distributor100B equally distributes an output signal from the amplifier90B. Similarly, the power combiner/distributor100C equally distributes an output signal from the amplifier90C. The amplifiers90D and90E amplify the signal equally distributed by the power combiner/distributor100B. Similarly, the amplifiers90F and90G amplify the signal equally distributed by the power combiner/distributor100C. The power combiner/distributor100D combines the output signals from the amplifiers90D and90E, and the power combiner/distributor100E combines the output signals from the amplifiers90F and90G. The power combiner/distributor100F combines the output signals from the power combiner/distributors100D and100E.

Thus, by distributing and amplifying the power in the first half of the circuit and combining the power with another in the later half of the circuit, a large power amplification is available as a whole circuit. Because each power combiner/distributor equally distributes the power in the same phase, no phase shifter for phase adjustment is required, and a wide band property can be obtained without causing a distribution phase variation.

Fifth Embodiment

In a fifth embodiment of the present invention, a radar apparatus is described as an example of a wireless apparatus in the claims.

FIG. 16is a block diagram illustrating a configuration of the radar apparatus according to the fifth embodiment. The radar apparatus includes a radiator130, an antenna device150, and an instructor140. The antenna device150includes a waveform generating circuit111, a signal processor112, a local oscillator121, mixers122and125, a power amplifying circuit200, a circulator123, and a low noise amplifier124.

The waveform generating circuit111generates a waveform of a transmission wave. The waveform (signal) is mixed with a signal of the local oscillator121by the mixer122, and is amplified in power by the power amplifying circuit200. The power amplifying circuit200corresponds to the power amplifying circuit200described in the fourth embodiment. The transmission signal passes the circulator123and is radiated from the radiator130. A reception signal is received by the radiator130, passes the circulator123, and is amplified by the low noise amplifier124. The reception signal is further mixed with the signal from the local oscillator121by the mixer125, and is inputted into the signal processor112.

Thus, the power combiner/distributor can be applied to the power amplifying circuit200included in a generating circuit of transmission waves.

Note that, “the waveguide” according to the embodiments is not limited to a hollow waveguide, and may be a dielectric body waveguide of which an electromagnetic wave propagation path is filled with inductive dielectric body(s) other than air.