JPH0918238A - Frequency mixer, transmitter, receiver and transmitter-receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image rejection filter of a simple constitution. SOLUTION: This device consists of a hybrid coupler 3 to which a local oscillation signal(LO) and a high frequency signal(RF) are inputted, a nonlinear element 5a which is connected to one of both output terminals of the coupler 3 via a transmission line 4a, a nonlinear element 5b which is connected to the other output terminal of the coupler 3 via a transmission line 4b, and a hybrid coupler 7 which connects together both elements 5a and 5b. Then λ(m/4±1/8) is secured as long as the difference of electric length is equal to the LO frequency between both lines 4a and 4b (λ: wavelength of transmission line, m: 0 or a natural number). Therefore, the RF and LO distribution phase differences supplied to the nonlinear elements are set at such levels based on the signal of an intermediate frequency signal terminal 8a that make a difference of ±90 deg. between the signals of an upper sideband(USB) and a lower sideband (LSB) at the terminal 8a. Thus the USB and LSB are separated from each other and outputted by the coupler 7, and an image rejection filter is obtained with no use of filters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency mixer for performing frequency conversion using a local oscillation signal in microwaves and millimeter waves, and a transmitter, receiver and transmitter / receiver using this frequency mixer. It is about.

[0002]

2. Description of the Related Art FIG. Maa
s "MICROWAVE MIXERS" (198
6. Arttech House) pp. 274-278
FIG. 4 is a cross-sectional view of a harmonic mixer configured by the waveguide shown in FIG. In the figure, 31a and 31b are waveguides and 3
2 is a dielectric substrate, 33 is a diode, 34a and 34b are low pass filters, 35a and 35b are strip conductors,
36 is an intermediate frequency signal terminal.

Next, the operation will be described. Waveguide 31a
The local oscillation signal input from is input to the diode 33 via the strip conductor 35a inserted in the waveguide 31a and the low pass filter 34a. On the other hand, the waveguide 31b
The high-frequency signal input from is input to the diode 33 via the strip conductor 35b inserted in the waveguide 31b. Here, the high frequency signal is approximately twice the frequency of the local oscillation signal frequency, and the low-pass filter 34a is configured to pass the local oscillation signal but not the high frequency signal. The high frequency signal input to the diode 33 is frequency-mixed with the second harmonic of the local oscillation signal, and an intermediate frequency signal, which is the frequency of the difference between the high frequency signal frequency and the second harmonic frequency of the local oscillation signal, is generated.

Since the diode 33 uses an anti-parallel diode pair, the second harmonic of the local oscillation signal is confined in the anti-parallel diode pair and does not leak out of the diode. Diode 3
The intermediate frequency signal generated in 3 is the low-pass filter 34.
a, strip conductor 35a, and low-pass filter 34
It is output from the intermediate frequency signal terminal 36 via b. Here, the low-pass filter 34b is configured to pass the intermediate frequency signal but not the local oscillation signal, and the local oscillation signal does not leak to the intermediate frequency signal terminal.

FIG. 27 shows the frequency spectrum at this time. On both sides of the frequency 2f _LO, which is twice the local intermediate frequency f _LO , the frequency band above the frequency f _USB (US
B: Upper Side Band) is a high frequency signal, and the lower frequency band (LSB: Lowe) of the frequency f _LSB.
r Side Band). The spectrum of the frequency 2f _LO is represented by the dotted line because the second harmonic of the local oscillation signal is confined in the antiparallel diode pair and does not leak out of the diode. At this time, the USB frequency (f _USB
-2f _LO ) and LSB is frequency (-f _LSB + 2f _LO )
Are converted to. These appear on the same frequency.

By the way, if USB is the desired signal, L
Since SB is an unnecessary signal, LS is required before down conversion.
It is necessary to remove B. Therefore, a high pass filter is used.

In the above description of the operation, the case where the high frequency signal and the local oscillation signal are frequency mixed has been described, but there is also a case where the intermediate frequency signal and the local oscillation signal are frequency mixed.

FIG. 28 shows the frequency spectrum at this time. The figure shows a case where the intermediate frequency signal of a frequency f _IF, upconverts the frequency twice 2f _LO of the local oscillator frequency f _LO. However, on both sides, a _USB with a frequency f USB
And a high frequency signal of LSB of frequency f _{LS B} are generated respectively.

By the way, if USB is the desired signal, L
Since SB is an unnecessary signal, LS after up conversion
It is necessary to remove B. Therefore, a high pass filter is used as in the case of down conversion.

As described above, the conventional frequency mixer outputs the frequency of the difference between the second harmonic of the local oscillator signal and the high frequency signal as an intermediate frequency signal. Since a filter is required outside the frequency mixer to separate the high frequency signal in the upper frequency band (USB) and the high frequency signal in the lower frequency band (LSB), the device becomes large and complicated. There was a problem that

As a frequency mixer for solving such a problem, A. Pospishil et al., "A MM
IC Subharmonically Pumped
SSB Modulator "1993 IEEE
MTT-S Digest, pp. 309-402. FIG. 29 shows the structure of a modulator using this frequency mixer. In the figure, 41 is a Wilkinson divider that distributes the modulated signal (frequency fc / 2), 42a and 42b are high-pass filters (HPF) that filter the distributed modulated signals, and 43a and 43b are intermediate frequency signals IF1. , IF2 are respectively modulated by the outputs of the HPFs 42a and 42b, 44a and 44b are high-pass filters that filter the outputs of the mixers 43a and 43b, and 45 is a combination of the outputs of the HPFs 44a and 44b and an RF signal (frequency fc). ) Output coupler.

The mixers 43a and 43b include couplers 46a and 46b and a low pass filter (LPF) 47, respectively.
a, 47b, low pass filter (LPF) 48a, 47
b, and an anti-parallel diode pair 49a, 49b
It consists of. The anti-parallel diode pairs 49a and 49b are formed by serially connecting two anti-parallel diode pairs connected in parallel to each other with opposite polarities.

According to the modulator of FIG. 29, when the intermediate frequency signal IF1 is input to the mixer 43a, or when the mixer 4a
When the intermediate frequency signal IF2 is input to 3b, the unwanted sideband LSB (or US
B) does not occur. But Wilkinson Divider 4
1, the couplers 45, 46a and 46b are required, which complicates the configuration.

[0014]

As described above, the conventional frequency mixer has a problem that the device becomes large and complicated because it requires a large number of dividers and couplers.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a frequency mixer, a transmitting device, a receiving device, and a transmitting / receiving device that are simple in structure and that do not output unnecessary sidebands. To aim.

[0016]

A frequency mixer according to a first aspect of the present invention has two sets of a plurality of terminals isolated from each other, and sets a plurality of signals input to the plurality of terminals of one set to be different from each other. A hybrid coupler that synthesizes with a phase difference and outputs to a plurality of terminals of the other set, a high-frequency signal terminal and a local oscillation signal terminal that are respectively connected to a plurality of terminals of one set of the hybrid coupler, and the hybrid coupler First connected to a plurality of terminals of the other set, respectively
Transmission line and a second transmission line, a first nonlinear element and a second nonlinear element connected to the first transmission line and the second transmission line, respectively, the first nonlinear element and the above A first connected to a second non-linear element, respectively
Of the intermediate frequency signal terminal and the second intermediate frequency signal terminal, the difference between the electrical length of the first transmission line and the electrical length of the second transmission line is approximately (m / 4 ± 1/8). ) Λ (where λ is the wavelength of the local oscillation signal in each transmission line, m:
It has a length corresponding to 0 or a natural number.

A frequency mixer according to a second aspect of the present invention is the first mixer described above.
The difference between the electrical length of the transmission line and the electrical length of the second transmission line is approximately (m / 2 ± 1/4) · λ (where λ is the wavelength of the local oscillation signal in each transmission line, m: The length corresponds to 0 or a natural number, and the harmonics of the local oscillation signal and the high frequency signal are mixed in frequency.

A frequency mixer according to a third aspect of the present invention has two sets of a plurality of terminals which are isolated from each other, and synthesizes a plurality of signals input to a plurality of terminals of one set with mutually different phase differences. A hybrid coupler for outputting to a plurality of terminals of the other set, a high-frequency signal terminal connected to one of the terminals of the one set of the hybrid coupler, a power distributor connected to a local oscillation signal terminal, and the hybrid coupler A first non-linear element and a second non-linear element respectively connected to a plurality of terminals of the other set and to the output terminal of the power distributor, the first non-linear element and the second non-linear element. The open stubs, which are respectively provided at the connection parts of the non-linear elements of the above with the hybrid coupler, are open for high frequency signals and short for local oscillation signals, and Respectively provided at the connection portion of the power divider 1 of the nonlinear element and the second non-linear element,
A short stub that is short-circuited with respect to a high-frequency signal and open with respect to a local oscillation signal, and a first stub connected to the first nonlinear element and the second nonlinear element, respectively.
And an intermediate frequency signal terminal and a second intermediate frequency signal terminal.

A frequency mixer according to a fourth aspect is the first mixer.
Of the non-linear element and the second non-linear element, which are not connected to the hybrid coupler, are connected to each other, and a short stub that is short-circuited to a high-frequency signal and open to a local oscillation signal is provided at this connection part. Is.

According to a fifth aspect of the present invention, the frequency mixer includes a hybrid coupler connected to the local oscillation signal terminal instead of the power distributor connected to the local oscillation signal terminal.

According to a sixth aspect of the present invention, the frequency mixer includes a power distributor connected to the high frequency signal terminal instead of the hybrid connected to the high frequency signal terminal.

According to a seventh aspect of the frequency mixer, a first transmission line and a second transmission line are provided between the local oscillation signal terminal and the first nonlinear element and the second nonlinear element, respectively. , The electrical length of the first transmission line and the second
The difference from the electrical length of the transmission line is approximately (m / 4 ± 1/8)
A length corresponding to λ (where λ is the wavelength of the local oscillation signal in each transmission line, m: 0 or a natural number).

In the frequency mixer according to claim 8, a first transmission line and a second transmission line are provided between the local oscillation signal terminal and the first nonlinear element and the second nonlinear element, respectively. , The electrical length of the first transmission line and the second
The difference from the electrical length of the transmission line is approximately (m / 2 ± 1/4)
A length corresponding to λ (where λ is the wavelength of the local oscillation signal in each transmission line, m: 0 or a natural number).

A frequency mixer according to a ninth aspect is the first mixer.
At least one of the transmission line and the second transmission line is provided with a coupling line whose tips are coupled to each other.

A frequency mixer according to a tenth aspect of the present invention includes a high frequency signal terminal, a first transmission line and a second transmission line each having one end connected to the high frequency signal terminal, and the first transmission line.
A first nonlinear element and a second nonlinear element respectively connected to the other transmission line and the other end of the second transmission line, and a local oscillation signal terminal connected to the second nonlinear element,
A first intermediate frequency signal terminal and a second intermediate frequency signal terminal respectively connected to the first non-linear element and the second non-linear element, respectively, the electrical length of the first transmission line and the second Is approximately m · λ (where λ is the wavelength of the local oscillation signal in the transmission line, m: 0
Or a natural number), and the first
The sum of the electrical length of the transmission line and the electrical length of the second transmission line is approximately (n + 1/8) · λ or approximately (n + 3 /
8) · λ (where λ is the wavelength of the local oscillation signal in the transmission line, n: 0 or a natural number).

According to an eleventh aspect of the present invention, in the frequency mixer, each of the first nonlinear element and the second nonlinear element is an antiparallel diode pair.

In a frequency mixer according to a twelfth aspect, the first nonlinear element and the second nonlinear element are diodes.

In the frequency mixer according to a thirteenth aspect, the first intermediate frequency signal terminal and the second intermediate frequency signal terminal are connected to a plurality of terminals of one set, and the plurality of terminals of the other set are connected. It is provided with a hybrid coupler to which the third intermediate frequency signal terminal and the fourth intermediate frequency signal terminal are connected.

In a frequency mixer according to a fourteenth aspect, the first nonlinear element and the second nonlinear element are formed on the same semiconductor substrate.

According to a fifteenth aspect of the present invention, a transmitting device radiates a radio wave to a space by receiving a frequency mixer for converting a modulated intermediate frequency signal into a high frequency signal based on a local oscillation signal and receiving the output of the frequency mixer. In a transmitting device including an antenna, the frequency mixer may be provided in any one of claims 1 to 1.
The frequency mixer according to any one of 4 above.

According to a sixteenth aspect of the present invention, there is provided a receiving device comprising: an antenna for receiving radio waves; and a frequency mixer for converting the output of the antenna into an intermediate frequency signal based on a local oscillation signal. The frequency mixer according to any one of claims 1 to 14.

A transmitting / receiving apparatus according to a seventeenth aspect is a transmitting / receiving apparatus including a transmitting apparatus and a receiving apparatus, wherein the transmitting apparatus is the transmitting apparatus according to the fifteenth aspect, and the receiving apparatus is the receiving apparatus according to the sixteenth aspect. Is.

[0033]

According to the invention of claims 1 and 2, the distribution phase difference of the high frequency signal and the distribution phase difference of the local oscillation signal by the hybrid coupler and the propagation of the high frequency signal by the first transmission line and the second transmission line. The phase difference and the propagation phase difference of the local oscillation signal are combined to give a predetermined phase difference to the high frequency signal and the local oscillation signal, respectively, and the first nonlinear element and the second nonlinear element are Frequency conversion processing is performed based on the high frequency signal and the local oscillation signal, and when the output signal from one of the intermediate frequency signal terminals is used as a reference, the upper sideband signal and the lower sideband that are approximately ± 90 ° out of phase with each other The signal is output to the other intermediate signal terminal.

In the third aspect of the invention, the hybrid coupler provides a predetermined distribution phase difference of the high frequency signal, and the first nonlinear element and the second nonlinear element perform frequency conversion based on the high frequency signal and the local oscillation signal. When the processing is performed and the output signal from one of the intermediate frequency signal terminals is used as a reference, the upper sideband signal and the lower sideband signal having different phases of approximately ± 90 ° are output to the other intermediate signal terminal. .

In a fourth aspect of the present invention, the short stub provided at the connection point connecting the sides of the first nonlinear element and the second nonlinear element that are not the connection side of the hybrid coupler to each other is the first nonlinear element. The high-frequency signal is short-circuited to both the non-linear element and the second non-linear element without affecting the local oscillation signal.

In the fifth aspect of the invention, the hybrid coupler connected to the local oscillation signal terminal gives a predetermined distribution phase difference to the local oscillation signal.

In the invention of claim 6, the power distributor connected to the high frequency signal terminal gives a predetermined phase difference to the high frequency signal.

In the inventions of claims 7 and 8,
A first transmission line and a second transmission line provided between the local oscillation signal terminal and the first nonlinear element and the second nonlinear element respectively have a predetermined phase difference with respect to the local oscillation signal. give.

In a ninth aspect of the present invention, the coupling line provided in at least one of the first transmission line and the second transmission line reduces a change in phase characteristic near the resonance point due to propagation delay. Stabilize the frequency conversion characteristics.

According to the tenth aspect of the invention, the first transmission line and the second transmission line give a predetermined propagation phase difference to the high frequency signal and the local oscillation signal, and the high frequency signal and the second nonlinearity. The element performs frequency conversion processing based on these high-frequency signals and local oscillation signals, and when the output signal from one of the intermediate-frequency signal terminals is used as a reference, the upper sideband signal and the lower sideband signal are approximately ± 90 ° out of phase with each other. The sideband signal of is output to the other intermediate signal terminal.

In the eleventh aspect of the present invention, the anti-parallel diode pair operates as the first nonlinear element and the second nonlinear element, and outputs a high frequency signal without outputting a harmonic of the local oscillation signal to the outside. And the harmonics of the local oscillator signal.

In the twelfth aspect of the present invention, the diode operates as the first nonlinear element and the second nonlinear element, and outputs a harmonic of the local oscillation signal.

In the thirteenth aspect of the invention, the first intermediate frequency signal terminal and the second intermediate frequency signal terminal are provided to the plurality of terminals of one set.
Of the third intermediate frequency signal terminal and the fourth intermediate frequency signal terminal are connected to a plurality of terminals of the other set, and the third intermediate frequency signal terminal and the third intermediate frequency signal terminal Only one of the upper frequency band signal and the lower frequency band signal is output to the fourth intermediate frequency signal terminal.

In the fourteenth aspect of the invention, the first nonlinear element and the second nonlinear element, which are formed on the same semiconductor substrate and have uniform characteristics, mix the frequencies efficiently.

In the fifteenth aspect of the present invention, the frequency mixer converts the modulated intermediate frequency signal into a high frequency signal based on the local oscillation signal, and the antenna receives the output of the frequency mixer and radiates a radio wave into space. To do.

In the sixteenth aspect of the invention, the antenna receives the radio wave, and the frequency mixer converts the output of the antenna into an intermediate frequency signal based on the local oscillation signal.

[0047]

【Example】

Embodiment 1 FIG. For convenience of description, the operation principle of the image rejection mixer will be described based on FIG. 4 before describing the operation of the frequency mixer of the first embodiment. FIG. 4 is an explanatory diagram of the operating principle of the frequency mixer, which includes 51a and 51b.
Is an IF output terminal (corresponding to the first and second intermediate frequency signal terminals), 52 is an RF input terminal, 53 is an equal distributor for distributing the RF signal into two, and 54 is a phase for one of the distributed signals. The phase shifter for delaying, 55 is the LO of the local oscillator 58.
An equal distributor that divides the output into two, and 56 is a distributed LO
It is a phase shifter that delays the phase of one of the signals. 5
Reference numerals 7a and 57b are second-order harmonic mixers that mix the RF signal and the LO signal. The mixers 57a and 57b are composed of anti-parallel diode pairs.

The mixer 57a receives a signal directly from the equal distributors 53 and 54. On the other hand, the mixer 57b includes the phase shifters 54, 5
Receive signal via 6. Therefore, the phases of the RF signal and the LO signal at RF-2 and LO-2, which are the input terminals of the mixer 57b, are the same as those at the input terminal of the mixer 57a, which is RF-.
1, LO-1 is delayed by a predetermined amount.

Next, the principle of operation will be generally described using equations. The phase shift amount of the phase shifter 54 is θ _RF + Δθ _RF , and the phase shift amount of the phase shifter 55 is θ _LO + Δθ _LO . Where Δθ _RF
And Δθ _LO are the errors of the phase shifters 54 and 56, respectively. Further, the voltage input to the RF terminal 2 is given by the following equation. Upper sideband (USB): V _U · cos (ω _U · t + φ _U ) (1) Lower side band (V _L · cos (ω _L · t + φ _L ) (2)

Then, the voltage at RF-1 in FIG. 4 is V _U · cos (ω _U · t + φ _U ) + V _L · cos (ω _L · t + φ _L ) (3) Further, the voltage at RF-2 in FIG. Is V _U · cos (ω _U · t + φ _U −θ _RF −Δθ _RF ) + V _L · cos (ω _L · t + φ _L −θ _RF −Δθ _RF ) (4)

The output voltage of the local oscillator 58 is given by the following equation. V _P · cos (ω _P · t + φ _P ) (5) However, ω _U > 2ω _P > ω _L. Then, L in FIG.
The voltage at O-1 is V _P · cos (ω _P · t + φ _P ) (6) Further, the voltage at LO-2 in FIG. 4 is V _P · cos (ω _P · t + φ _P −θ _LO −Δθ _LO ). (7)

Since the mixers 57a and 57b are second-order harmonic mixers, they output a signal having a frequency difference between the second harmonic of the local oscillation signal and the high frequency signal as an intermediate frequency signal. Therefore, the voltage at IF-1 in FIG. 4 is αV _U V _P · cos {(ω _U −2ω _P ) t + (φ _U −2φ _P )} + α V _L V _P · cos {(2ω _P −ω _L ). _{t- (φ L -2φ P)}} (8)

[0053] Further, the voltage at the IF-2 of FIG. _{4, αV U V P · cos {} (ω U -2ω P) t + (φ U -2φ P) - (θ RF -2θ LO) - (Δθ RF - 2Δθ _LO )} + αV _L V _P · cos {(2ω _P −ω _L ) t− (φ _L −2φ _P ) + (θ _RF −2θ _LO ) + (Δθ _RF −2Δθ _LO )} (9) where , Α are coefficients representing the mixer efficiency.

In equations (8) and (9), the term converted from the USB signal and the term converted from the LSB signal are individually considered. Regarding the signal obtained by converting the USB signal, the phase difference between IF-1 and IF-2 is − (θ _RF −2 θ _LO ) (10) in the same manner as the LSB signal is converted with IF-1 as the reference. (Θ _RF −2 θ _LO ) (11) The error term is ignored. As you can see from this,
The phase difference between the IF signal appearing at the two terminals IF-1 and the IF signal appearing at IF-2 differs between the USB signal and the LSB signal.

By the way, the frequency mixer of FIG.
In order to operate as an image rejection mixer that outputs only one of the signal or the LSB signal, the phase of the USB signal given by equation (10) and the phase of the LSB signal given by equation (11) are ± 90 °. And then
An intermediate frequency band 90 ° hybrid coupler 7 is provided at the output of the frequency mixer shown in FIG. Then, the USB signal is output to one of the outputs of the hybrid coupler 7 and the LS signal is output to the other.
B signal appears.

This will be described with reference to FIG. It is assumed that the USB signal phase of the input terminal IF-2 is + 90 ° and the LSB signal phase is −90 °. U appearing at OUT-1
Considering the SB signal, due to the nature of the 90 ° hybrid coupler 7, the signal from IF-1 is not delayed and IF-2
Since the signal from is delayed by 90 °, OUT-1 has 0 °
90 ° + 90 ° = 18 with delayed signal (from IF-1)
A signal delayed by 0 ° (from IF-2) appears. Since they have opposite polarities, they cancel each other out and are not output. That is, no USB signal appears at OUT-1. On the other hand, LS
Considering the B signal, 0 ° (IF-
Delayed signal and -90 ° + 90 ° = 0 ° (IF
-2) A delayed signal appears. Since they have the same polarity, they are not canceled. Therefore, OUT-1 has L
Only the SB signal appears. Similarly, in OUT-2,
Only the USB signal appears. USB signal phase is -90
The same applies when the phase of the LSB signal is + 90 °.

Here, θ _{RF is set} to −180 °, −90 °, 0
°, 90 °, 180 °, θ _LO -180 °, -90 °,
When -45 °, 0 °, 45 °, 90 °, 180 °, the phase lag and LSB of the USB signal in IF-2 are set.
The specific conditions for setting the signal phase delay to ± 90 ° are as follows according to the equations (10) and (11).

At this time, the influence of the errors of the phase shifters 54 and 56 is that the output of OUT-1 is-(Δθ _RF -2Δ
θ _LO ), and OUT− is (Δθ _RF −2Δθ _LO ).

Although the above description has been given by taking the case of the down converter as an example, the same applies to the case of the up converter.

Next, the frequency mixer of the first embodiment will be described. FIG. 1 is a block diagram of a frequency mixer according to an embodiment of the present invention. In the figure, 1 is a local signal (LO) terminal, 2 is a high frequency signal (RF) terminal, and 3 is LO.
And RF are divided into two with equal amplitude and 90-degree phase difference, 90-degree hybrid couplers 4a and 4b have predetermined transmission path lengths, and transmission lines 5a that transmit the output of the 90-degree hybrid coupler 3 respectively. 5b are transmission lines 4a,
Anti-parallel diode pair receiving the output of 4b, 6a and 6b are anti-parallel diode pair 5
a low-pass filter (LP
F) and 7 are intermediate frequency band 90-degree hybrid couplers for combining the intermediate frequency signals output from the LPFs 6a and 6b with a 90-degree phase difference, and 8a and 8b are connected to the output of the intermediate frequency band 90-degree hybrid coupler 7, respectively. It is an intermediate frequency signal (IF) terminal. The terminals 8a and 8b correspond to third and fourth intermediate frequency signal terminals.

The electrical length of the transmission line 4a and the electrical length of the transmission line 4b differ by λ / 8 (λ: wavelength) at the local oscillation signal frequency f _LO . Therefore, the phase of the intermediate frequency signal at the output end of the transmission line 4a differs from the phase of the intermediate frequency signal at the output end of the transmission line 4b by 45 degrees (the output end of the transmission line 4a is delayed in phase). Further, since the frequency f _{RF of the} high frequency signal and the intermediate frequency f _LO have a relationship of f _RF = 2f _LO , the phase of the high frequency signal at the output end of the transmission line 4a and the phase of the high frequency signal at the output end of the transmission line 4b. And 90 degrees (phase is delayed at the output end of the transmission line 4a).

Next, the operation will be described. The frequency mixer in FIG. 1 mixes a local oscillation signal and an intermediate frequency signal to output a high frequency signal, a down converter that mixes the local oscillation signal and the high frequency signal and outputs an intermediate frequency signal, It is possible to perform both operations. here,
The case of operating as a down converter will be described.

The local oscillator signal input from the local oscillator signal terminal 1 is split into two by the 90-degree hybrid coupler 3 with equal amplitude and 90-degree phase difference. One of the two locally distributed signals is input to the anti-parallel diode pair 5a via the transmission line 4a. The other local signal is input to the anti-parallel diode pair 5b via the transmission line 4b. Here, since the transmission line 4a and the transmission line 4b electrically differ by λ / 8 in the local signal frequency, the phase of the local signal input to the two anti-parallel diode pairs 5a and 5b is 45 degrees. different.

On the other hand, the high-frequency signal input from the high-frequency signal terminal 2 is equalized in amplitude by the 90-degree hybrid coupler 3.
It is divided into two with a 90-degree phase difference. One of the two locally distributed signals is input to the anti-parallel diode pair 5a via the transmission line 4a. Here, since the transmission line 4a and the transmission line 4b electrically differ by λ / 8 in the local oscillation signal frequency, two anti-parallel diode pairs 5a of a high frequency signal having a frequency approximately twice that of the local oscillation signal are formed. The phases input to 5b differ by 180 degrees.

The local oscillation signal and the high frequency signal input to the anti-parallel diode pair are mixed in frequency. When frequency-mixed, it is frequency-mixed with the second harmonic of the local oscillator signal, so the phase difference of the second harmonic of the local oscillator signal in each diode is twice the phase difference at the time of input. Phase difference.

The above will be described in detail. A in FIG.
1, A2 (90 ° hybrid coupler output end), B
1, B2 (I / O terminal of anti-parallel diode pair)
The phase lag at is as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−90 °, 90 ° + y−45 ° where x is The phase delay with respect to the high frequency signal by the transmission line 4a and y are the phase delay with respect to the local oscillation signal by the transmission line 4a.

Therefore, with reference to the B1 end, the phase at the B2 end is as follows. θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: -180 °, 45 ° = 180 °

Since this corresponds to the condition 6 described above, the intermediate frequency band 90 is detected by the mixers 5a and 5b.
° Input end of hybrid coupler 7 (C1, C2: first,
The phase difference between the USB signal and the LSB signal of the intermediate frequency signal applied to the second intermediate frequency signal end) is ± 90 °.

In this way, the intermediate frequency signal of the frequency difference between the second harmonic of the local oscillation signal generated by frequency mixing and the high frequency signal is passed through the low pass filters 6a and 6b, respectively. 9 with 90 degree hybrid coupler 7
They are combined with a 0 degree phase difference. As described above, when combined, the upper sideband (USB) signal and the lower sideband (LSB) signal are separated and output.
The frequency mixer of FIG. 1 operates as an image rejection mixer.

That is, as shown in FIG.
_{Even if a} USB signal and an LSB signal are present on both sides of the _LO , the US signal is output to the intermediate frequency signal terminal 8a (or 8b).
Only the B signal appears.

In FIG. 1, the electrical length of the intermediate transmission lines 4a and 4b at the local signal frequency is λ / 8 (= electrical length 4
However, the present invention is not limited to this, and the difference in electrical length is (m / 4 + 1/8) λ or (m
/ 4-1 / 8) λ may be used (however, m: 0 or a natural number).

When m = 1, (m / 4 + 1/8) λ =
(3/8) λ, and the difference in electrical length is 135 °. At this time, the phases at A1, A2, B1 and B2 in FIG. 1 are as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−270 °, 90 ° + y−135 °

Therefore, θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: -360 °, -45 ° = 0 °, or θ _RF θ _LO θ _RF θ _LO B1: 0 °, 45 ° B2 : 0 ° and 0 °. This corresponds to the above condition 1.

When m = 2, (m / 4 + 1/8)
λ = (5/8) λ, and the difference in electrical length is 225 °. At this time, the phases at A1, A2, B1 and B2 in FIG. 1 are as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−450 °, 90 ° + y−225 °

Therefore, θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: −540 °, −135 ° = −180 ° Alternatively, θ _RF θ _LO θ _RF θ _LO B1: 180 °, 135 ° B2: 0 ° and 0 °. This corresponds to the above condition 7.

When m = 3, (m / 4 + 1/8)
λ = (5/8) λ, and the difference in electrical length is 315 °. At this time, the phases at A1, A2, B1 and B2 in FIG. 1 are as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−630 °, 90 ° + y−315 ° = 0 ° + x + 90 °, 90 ° + y + 45 °

Therefore, θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: 0 °, 135 °. This corresponds to the above condition 2. Below, m =
.., 5, ... Correspond to either condition in the same manner.

Similarly, for (m / 4-1 / 8) λ, m
When = 0, (m / 4−1 / 8) λ = − (1/8) λ, and the difference in electrical length is 45 °. Therefore, it is the same as the case of FIG. Further, the same applies to m = 1, 2, 3, ...

When the frequency converter of FIG. 1 is used as an up converter, the intermediate frequency signal terminals 8a,
IF signal from 8b, RF from high frequency signal terminal 2
Take out the signal. At this time, as shown in FIG. 3, the intermediate frequency signal input to the intermediate frequency signal terminal 8a (or 8b) is converted to only one of the frequencies 2f _LO .

As described above, according to the first embodiment, when operating as a down converter, only one of the USB signal and the LSB signal can be taken out as an IF signal without using a filter or the like.
When operating as an up-converter, the IF signal can be converted into only one of the USB signal and the LSB signal without using a filter or the like. Further, in order to configure the frequency converter, only two hybrid couplers and one set of transmission lines are required, which has the effect of greatly simplifying the configuration and enabling miniaturization.

Embodiment 2 FIG. In Example 1, the difference in the electrical length of the transmission line connected to the hybrid coupler 3 was set to λ / 8 at the local frequency, but when the nonlinear element (mixer) used and the line to be connected are poorly matched, The local signal may leak to the high frequency signal terminal. In such a case, by changing the electrical length of the transmission line, it is possible to prevent the local oscillation signal from leaking to the high frequency signal terminal while obtaining the same effect as that of the first embodiment. FIG. 6 is a block diagram showing an embodiment of the frequency mixer according to the second embodiment of the present invention.

Since the transmission line 4a and the transmission line 4b are electrically different from each other in the local signal frequency by λ / 4, the phase difference between the local signals input to the two anti-parallel diode pairs 5a and 5b is 0. It becomes degree. Further, the phase difference between the high frequency signals input to the two anti-parallel diode pairs 5a and 5b is 90 degrees.

The above will be described in detail. A in FIG.
1, A2 (90 ° hybrid coupler output end), B
1, B2 (I / O terminal of anti-parallel diode pair)
The phase lag at is as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−180 °, 90 ° + y−90 ° where x is The phase delay with respect to the high frequency signal by the transmission line 4a and y are the phase delay with respect to the local oscillation signal by the transmission line 4a.

Therefore, with reference to the B1 end, the phase at the B2 end is as follows. θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: -270 °, 0 ° = 90 °

Since this corresponds to the condition 3 described above, it is detected by the mixers 5a and 5b and the intermediate frequency band 90 is detected.
The phase difference between the USB signal of the intermediate frequency signal and the LSB signal applied to the input end of the hybrid coupler 7 is ± 90 °.

Thereafter, as in the case of the first embodiment, the intermediate frequency signal of the frequency difference between the second harmonic of the local oscillation signal generated by frequency mixing and the high frequency signal is processed by the low pass filter 6
A 90-degree phase difference is combined by the 90-degree hybrid coupler 7 in the intermediate frequency band via a and 6b. When combined, it operates as an image rejection mixer in which an upper sideband (USB) signal and a lower sideband (LSB) signal are separated and output.

In FIG. 6, the electrical length of the intermediate transmission lines 4a and 4b is λ / 4 (= electrical length 9 at the local oscillator signal frequency).
However, the electric length difference is (m / 2 + 1/4) λ, or (m
It may be / 2-1 / 4) λ (however, m: 0 or a natural number).

When m = 1, (m / 2 + 1/4) λ =
(3/4) λ, and the difference in electrical length is 270 °. At this time, the phases at A1, A2, B1 and B2 in FIG. 6 are as follows. θ _RF θ _LO θ _RF θ _LO A1: 90 °, 0 ° A2: 0 °, 90 ° B1: 90 ° + x, 0 ° + y B2: 0 ° + x−540 °, 90 ° + y−270 °

Therefore, θ _RF θ _LO θ _RF θ _LO B1: 0 °, 0 ° B2: -630 °, -180 ° = 90 °, = 180 °. This corresponds to the above condition 5. Below, m =
Similarly, any of the conditions 2, 3, ...

Similarly, with respect to (m / 2−1 / 4) λ, m
When = 0, (m / 2−1 / 4) λ = − (1/4) λ, and the difference in electrical length is 90 °. Therefore, it is the same as the case of FIG. Further, the same applies to m = 1, 2, 3, ...

Here, the anti-parallel diode pair 5
The local oscillator signals reflected at a and 5b are again combined by the 90-degree hybrid coupler 3 with a 90-degree phase difference, and the combined phase difference at the local oscillator signal terminal 1 becomes 0 degrees, but at the high-frequency signal terminal 2. The combined phase difference is 180 degrees. Therefore, the local oscillator signal reflected by the anti-parallel diode pair 5a, 5b is output only to the local oscillator signal terminal 1 and is not output to the high frequency signal terminal 2. Therefore, according to the second embodiment, by setting the electrical length of the transmission line to 90 ° in the intermediate frequency band, the effect similar to that of the first embodiment is obtained, and the local oscillation signal further leaks to the high frequency signal terminal. Can be prevented.

Embodiment 3 FIG. FIG. 7 is a block diagram of the frequency mixer of the third embodiment. In the figure, 9a and 9b
Are band-pass filters, which are provided between the mixers 5a and 5b and the 90 ° hybrid coupler 3 and pass high-frequency signals, and 10a and 10b are RFs of the mixers 5a and 5b.
Open stubs provided on the terminal side, 11a,
Reference numeral 11b is a short stub provided on the IF terminal side of each of the mixers 5a and 5b, 12 is a power distributor that distributes the LO signal in equal phase and with equal amplitude, and supplies the LO signal to the mixers 5a and 5b.
Reference numeral 13 is a terminating resistor provided at the other end of the 90 ° hybrid 3.

Next, the operation will be described. The frequency mixer operates both an up converter that mixes a local oscillator signal and an intermediate frequency signal and outputs a high frequency signal, and a down converter that mixes a local oscillator signal and a high frequency signal and outputs an intermediate frequency signal. However, here, a case where it operates as a down converter will be described.

The local oscillator signal input from the local oscillator signal terminal 1 is split into two by the power distributor 12 with equal amplitude and equal phase, and is input to the anti-parallel diode pairs 5a and 5b, respectively.

The high-frequency signal input from the high-frequency signal terminal 2 is equal in amplitude to 90
The signals are divided into two by the phase difference and are input to the anti-parallel diode pairs 5a and 5b through the band-pass filters 9a and 9b which pass only the high frequency signal. The high frequency signal reflected by the anti-parallel diode is
It is synthesized by the 90-degree hybrid coupler 3 and absorbed by the terminating resistor.

Here, the anti-parallel diode pair 5
open stub 10 connected to a and 5b respectively
The electrical lengths of a and 10b and the short stubs 11a and 11b are approximately λ / 4 at the local oscillation signal frequency. Therefore, the terminals of the anti-parallel diode pairs 5a and 5b on the side to which the open stubs 10a and 10b are connected are short-circuited at the frequency of the local oscillator signal and open at the frequency of the high frequency signal which is approximately twice the frequency of the local oscillator signal. Become. Also, anti-parallel diode pair 5
The terminals of a and 5b to which the short stubs 11a and 11b are connected are open at the local oscillator signal frequency, and are short-circuited at a high frequency signal frequency that is approximately twice the local oscillator signal frequency.

At this time, the difference between the phase of the RF signal and the LO signal supplied to the anti-parallel diode pair 5a, which is a mixer, and the phase of the RF signal and the LO signal supplied to the anti-parallel diode pair 5b is 90, respectively.
° (RF signal) and 0 ° (LO signal). This corresponds to the condition 3 described above. Therefore, the frequency mixer of FIG. 7 operates as an image rejection mixer. Note that FIG. 7 shows the case of the condition 3, but other conditions 1
Needless to say, it may be the case where the above conditions are satisfied.

As described above, according to the third embodiment, the local oscillation signal and the high frequency signal can be separated without using a filter as in the first embodiment.

Embodiment 4 FIG. In the third embodiment, the local oscillator signal is divided into two by the power divider and two short stubs are used, but the same effect can be obtained by using one short stub. FIG. 8 is a block diagram of the frequency mixer of the fourth embodiment.

The frequency mixer of FIG. 8 does not include a power divider, but the LO terminal 1 is directly connected to the anti-parallel diode pairs 5a and 5b. Also, 1 at this connection point
Two short stubs 11 are connected. The other points are the same as in the case of FIG. 7. The same applies to the operation. In the frequency mixer of FIG. 8, the phase difference between the signals supplied to the mixers 5a and 5b is 9 as in the case of FIG.
They are 0 ° (RF signal) and 0 ° (LO signal), which corresponds to the condition 3 described above. Therefore, the frequency mixer of FIG. 8 operates as an image rejection mixer.

As described above, according to the third embodiment, the local oscillation signal and the high frequency signal can be separated without using a filter as in the first embodiment.

Example 5. In the third embodiment, the local oscillation signal is input to the two anti-parallel diode pairs with the same phase and the same amplitude, but the same is true even if the local oscillation signal is input to the two anti-parallel diode pairs with a 90-degree phase difference. The effect of is obtained.

FIG. 9 is a block diagram of the frequency mixer of the fifth embodiment. In the figure, 3a is a 90-degree hybrid coupler provided for distributing the RF signal, which is the same as the 90-degree hybrid coupler 3 in FIG. 3b is a 90-degree hybrid coupler provided for distributing the LO signal. The 90-degree hybrid coupler 3b is provided instead of the power distributor 12 in FIG. The other components are the same as those in FIG.

In the frequency mixer of FIG. 9, the 90-degree hybrid coupler 3b has a phase difference of 90 ° with respect to the mixers 5a and 5b.
To supply the LO signal. Therefore, in the frequency mixer of FIG. 9, the phase difference between the signals supplied to the mixers 5a and 5b is 90 ° (RF signal) and 90 ° (LO signal),
It corresponds to the condition 4 described above. Therefore, the frequency mixer of FIG. 9 operates as an image rejection mixer. Although FIG. 9 shows the case of the condition 4, it goes without saying that the other conditions 1 to 7 may be satisfied.

As described above, according to the fifth embodiment, the local oscillation signal and the high frequency signal can be separated without using a filter as in the first embodiment.

Embodiment 6 FIG. In the third embodiment, the high frequency signal was distributed with a phase difference of 90 °, and the local oscillation signal was distributed with the same phase and the same amplitude, which were respectively input to two anti-parallel diode pairs. Not limited to this, high-frequency signals are distributed with a 180 ° phase difference, and local signals are
Similar effects can be obtained by distributing with a phase difference of 5 degrees.

FIG. 10 is a block diagram of the sixth embodiment. In the figure, 9c and 9d are bandpass filters that pass LO signals, and 59 is a 180 ° hybrid coupler that distributes RF signals with a 180 ° phase difference. The other components are the same as those shown in FIG. 1 or 7.

From the two distribution terminals of the power distributor 12 to the anti-parallel diode pairs 5a and 5b via the band-pass filters 9c and 9d which pass only the local oscillation signal, respectively.
The O signal is supplied. Transmission lines 4a and 4b are provided in these connection lines, respectively. The difference between the lengths of these transmission lines 4a and 4b is electrically set to differ by λ / 8 in the local oscillation signal frequency, and the local oscillation signal is applied to the two anti-parallel diode pairs 5a and 5b by 45 degrees. The phase difference is input. This point is similar to the case of the first embodiment.

On the other hand, the RF signal is input by the 180 ° hybrid coupler 59 to the two anti-parallel diode pairs 5a and 5b with a phase difference of 180 °. Therefore, in the frequency mixer of FIG.
The phase difference of the signals supplied to b is 180 ° (RF signal),
45 ° (LO signal), which corresponds to the condition 6 described above. Therefore, the frequency mixer of FIG. 10 operates as an image rejection mixer.

Anti-parallel diode pair 5a, 5b
The intermediate frequency signal of the frequency difference between the second harmonic of the local oscillation signal generated by frequency mixing and the high frequency signal is synthesized through the low pass filters 6a and 6b, respectively, and then the intermediate frequency signal is generated. It is output from the terminals 8a and 8b.

As described above, according to the sixth embodiment, the local oscillation signal and the high frequency signal can be separated without using a filter as in the first embodiment.

As shown in FIG. 11, the RF signal may be distributed by the power distributor 12b in equal phase and amplitude. In the frequency mixer of FIG. 11, the mixer 5
The phase difference between the signals supplied to a and 5b is 0 ° (RF signal) and 45 ° (LO signal), which corresponds to the condition 1 described above. Therefore, the frequency mixer of FIG. 11 also operates as an image rejection mixer. Needless to say, the conditions are not limited to those of the sixth embodiment, and other conditions 1 to 7 may be satisfied. The distribution phase difference of RF is 0 °, 90 °, 180 °, and the transmission line 4
The difference in electrical length between a and 4b is (m / 4 ± 1/8) λ,
(M / 2 ± 1/4) λ (where λ is the wavelength of the local oscillation signal in each transmission line, m: 0 or a natural number).

Example 7. In the sixth embodiment, the lengths of the transmission lines from the two distribution terminals of the power distributor 12 to the anti-parallel diode pair are electrically different from each other by λ / 8 in the local oscillation signal frequency, and the power distribution is divided into two. Although the phase difference of the local oscillation signal is set to 45 degrees, the same effect can be obtained by using another method.

FIG. 12 is a block diagram of the frequency mixer of the seventh embodiment. In the figure, reference numeral 14 is a coupled line provided between the LO terminal 1 and the anti-parallel diode pair 5a and having its tip short-circuited.

From the two distribution terminals of the power distributor 12, one is connected to the anti-parallel diode pair via the transmission line 4b and the other to the anti-parallel diode pair via the coupling line 14 and the transmission line 4a whose ends are short-circuited. Therefore, the local oscillation signal is input to the two anti-parallel diode pairs 5a and 5b with a phase difference of 45 degrees. This point is similar to the case of the sixth embodiment.

On the other hand, the RF signal is input by the 180 ° hybrid coupler 59 to the two anti-parallel diode pairs 5a and 5b with a phase difference of 180 °. Therefore, in the frequency mixer of FIG. 12, the mixers 5a, 5
The phase difference of the signals supplied to b is 180 ° (RF signal),
45 ° (LO signal), which corresponds to the condition 6 described above. Therefore, the frequency mixer of FIG. 12 operates as an image rejection mixer.

By the way, when the coupled line 14 is provided, as shown in FIG.
As shown in the phase-frequency characteristic diagram of, the change of the phase φ ₀ becomes gradual in the vicinity of the specific frequency f ₀ , and a flat portion appears in the characteristic graph. That is, in the vicinity of the frequency f ₀ , since the change in the passing phase is not proportional to the frequency due to the propagation delay, the 45-degree phase difference can be realized in a wider band than the case where the phase difference is created only by the transmission line. Therefore, the frequency mixer of the seventh embodiment can operate as an image rejection filter for a wider LO frequency. It goes without saying that the combination of the transmission line and the coupling line can be applied to the case of the above-described first embodiment and the like.

Example 8. In the seventh embodiment, the high frequency signal is equalized with a 180 degree hybrid coupler,
It was divided into two with a phase difference, but with a power amplifier, an equal amplitude,
Even if the phases are equally distributed, the same action and effect can be obtained. FIG.
FIG. 16 is a block diagram of a frequency mixer of the eighth embodiment.
In the figure, 12b is a power distributor provided in place of the 180-degree hybrid coupler 59 of FIG.
The RF signal is distributed with equal amplitude and equal phase.

The local oscillator signal has an equal amplitude in the power divider 12a,
After being divided into two parts with the same phase, one is through the transmission line 4b, and the other is the coupled line 14 and the transmission line 4 whose tips are short-circuited.
They are respectively input to the anti-parallel diode pair with a phase difference of 45 degrees via a.

On the other hand, the high frequency signal is split into two by the power distributor 12b with equal amplitude and phase, and then input to the anti-parallel diode pair via the band pass filters 9a and 9b which pass only the high frequency signal. To be done.

Therefore, in the frequency mixer of FIG. 14, the phase difference between the signals supplied to the mixers 5a and 5b is 0 °.
(RF signal) and 45 ° (LO signal), which corresponds to the condition 1 described above. Therefore, the frequency mixer of FIG. 14 operates as an image rejection mixer.

Anti-parallel diode pair 5a, 5b
The intermediate frequency signal of the frequency difference between the second harmonic of the local oscillation signal generated by frequency mixing and the high frequency signal is synthesized through the low pass filters 6a and 6b, respectively, and then the intermediate frequency signal is generated. It is output from the terminals 8a and 8b.

As described above, according to the eighth embodiment, the local oscillator signal and the high frequency signal can be separated without using a filter as in the first embodiment.

Example 9. FIG. 15 is a block diagram of the frequency mixer of the ninth embodiment. In the figure, 4c, 4
d is the RF terminal 2 and the anti-parallel diode pair 5a,
5b is a transmission line provided between them and 15 is an RF
It is a band elimination filter provided between the terminal and the transmission lines 4c and 4d. The electrical lengths of the transmission lines 4c and 4d are the same, and each is λ / 16 (λ: wavelength at LO frequency).

Next, the operation will be described. The local oscillator signal input from the local oscillator signal terminal 1 is divided into two after passing through the bandpass filter 9. One of the divided parts is directly input to the anti-parallel diode 5b. On the other hand, the anti-parallel diode 5a is electrically connected via transmission lines 4a and 4b having a length of λ / 16 at the local signal frequency.
Is input to The LO signals are delayed by 22.5 ° on the transmission lines 4a and 4b, respectively. Therefore, the LO signal input to the anti-parallel diode pair 5a is
The phase is delayed by 45 ° from the LO signal input to the anti-parallel diode pair 5b.

On the other hand, the high frequency signal input from the high frequency signal terminal 2 reflects only the local oscillation signal in the band elimination filter 1
5 and then split into two, and the transmission lines 4a, 4b
Through anti-parallel diode pair 5a, 5b
Respectively. The electrical length of the path from the RF terminal 2 to the anti-parallel diode pair 4a and the electrical length of the path to 4b are the same. Therefore, the phase of the RF signal input to the anti-parallel diode pair 5a and the phase of the RF signal input to the anti-parallel diode pair 5b are the same.

That is, in the frequency mixer of FIG.
The phase difference between the signals supplied to the mixers 5a and 5b is 0 ° (R
F signal) and 45 ° (LO signal), which corresponds to the condition 1 described above. Therefore, the frequency mixer of FIG.
Operates as an image rejection mixer.

Two anti-parallel diode pairs 5
The local oscillation signal and the high frequency signal input to a and 5b are mixed in frequency. When frequency mixed, it is frequency mixed with the second harmonic of the local oscillator signal. The intermediate frequency signal of the frequency difference between the second harmonic of the local oscillation signal generated by frequency mixing and the high frequency signal is passed through the low-pass filters 6a and 6b at the intermediate frequency band 90-degree hybrid coupler 7, 9
They are combined with a 0 degree phase difference. When combined, it operates as an image rejection mixer in which an upper sideband (USB) signal and a lower sideband (LSB) signal are separated and output.

If the electrical lengths of the transmission lines 4c and 4d are 3λ / 16 (67.5 °), Condition 2 is satisfied, and the transmission lines 4c and 4d similarly operate as an image rejection mixer. Generally speaking, the conditions for the electrical length of the transmission lines 4c and 4d are as follows. (1) The difference in electrical length between the transmission lines 4c and 4d is approximately mλ (m
= 0, 1, 2, ...) (2) The sum of electrical lengths between the transmission lines 4c and 4d is approximately (n + 1).
/ 8) λ or (n + 3/8) λ (n = 0, 1, 2, ...
・ ・)

As described above, according to the ninth embodiment, the local oscillation signal and the high frequency signal can be separated without using a filter as in the first embodiment.

Embodiment 10 FIG. In the first to ninth embodiments, the anti-parallel diode pair is used as the non-linear element so that the even-order harmonic signals of the local oscillation signal remain in the diode and are not output to the outside. However, by using different types of nonlinear elements, it becomes possible to output even-order harmonic signals of the local oscillation signal and operate as a multiplier.

FIG. 16 is a block diagram of the frequency mixer of the tenth embodiment. In the figure, 17a and 17b are diodes. The diodes 17a and 17b are shown in FIG.
5 is provided in place of the anti-parallel diode pair 5a, 5b.

The basic operation of the frequency mixer of FIG.
Although it is the same as that of FIG. 15, since the diodes are used as the mixers, the harmonic signals are output from the diodes 17a and 17b, and the harmonics are outputted from the diodes 17a and 17b by the transmission lines 4c and 4d.
These two signals, which are out of phase by 0 °, are combined and output.

Embodiment 11 FIG. In Examples 1 to 10 described above, the frequency mixer was used for frequency conversion from the RF signal to the LO signal or from the LO signal to the RF signal. However, they can be used as quadrature modulators,
This has the effect of simplifying the configuration.

FIG. 17 is a block diagram of the quadrature modulator of the eleventh embodiment. This quadrature modulator is obtained by removing the intermediate frequency band 90 ° hybrid coupler 7 from the frequency mixer of FIG.

Next, the operation will be described. The second harmonic of the carrier wave input from the local oscillator signal terminal 1 is modulated by the low frequency baseband signals input from the intermediate frequency signal terminals 8a and 8b, respectively.

Here, the anti-parallel diode pair 5
Since the phase difference of the carrier waves input to a and 5b is 45 degrees,
The two modulated waves obtained by modulating the second harmonic of the carrier wave have a phase difference of 90 degrees. The power divider 12b combines the modulated waves having a phase difference of 90 degrees in the same phase to operate as a quadrature modulator. According to the eleventh embodiment, a quadrature modulator can be configured with a simple configuration without using a filter.

Embodiment 12 FIG. In the eleventh embodiment, the carrier wave is input to the two anti-parallel diode pairs with a phase difference of 45 degrees and the modulated waves are combined in the same phase. However, the carrier wave is input to the two anti-parallel diode pairs in the same phase. Also, the same effect can be obtained. FIG. 18 shows this embodiment 12
3 is a block diagram of a quadrature modulator of FIG. This quadrature modulator
9 is a diagram in which the 90 ° hybrid coupler 7 in the intermediate frequency band is removed from the frequency mixer of FIG.

The carrier wave input to the local oscillator signal terminal 1 is split into two by the power divider 12 with equal amplitude and equal phase, and then input to the anti-parallel diode pairs 5a and 5b, respectively.

Anti-parallel diode pair 5a, 5b
The modulated waves respectively generated in
Input to the 90 degree hybrid coupler 3 via b respectively,
They are combined with a 90-degree phase difference. According to this Example 12,
The quadrature modulator can be configured with a simple configuration without requiring a filter.

Example 13. FIG. 19 is a block diagram of the quadrature modulator according to the thirteenth embodiment. This quadrature modulator is obtained by removing the intermediate frequency band 90 ° hybrid coupler 7 from the frequency mixer of FIG.

The basic operation is the same as in the eleventh and twelfth embodiments. According to the thirteenth embodiment, a quadrature modulator can be configured with a simple configuration without using a filter.

Embodiment 14 FIG. In the above-described embodiment, there are some which use two non-linear elements, but if the characteristics of these two non-linear elements are not the same, the efficiency will deteriorate.
Therefore, by forming two non-linear elements on the same semiconductor substrate, it becomes possible to obtain a plurality of non-linear elements with uniform characteristics.

FIG. 20 is a specific circuit pattern diagram of the frequency mixer of FIG. In addition, FIG. 21 is a specific pattern diagram of the semiconductor substrate 20 of FIG. In these figures, 18a and 18b are dielectric substrates, and 19a and 19b.
Is a metal wire, 20 is a semiconductor substrate, 21a and 21b are electrodes, and 22 is a via hole.

As can be seen from these figures, the circuit is formed on the dielectric substrates 18a and 18b, and the substrates are connected by metal wires 19a and 19b. The diode which is a non-linear element is formed by integrating two diodes on a semiconductor substrate 20 mounted on a dielectric substrate 18a. The connection between the dielectric substrate 18a and the semiconductor substrate 20 is made via a via hole 22 and a metal wire (not shown).

According to the fourteenth embodiment, since the antiparallel diode pair which is a non-linear element is integrally formed on the semiconductor substrate, these characteristics can be made uniform.
Therefore, the efficiency of the frequency mixer is improved. The same applies when the nonlinear elements are the diodes 17a and 17b.

Embodiment 15 FIG. Although only the non-linear element is integrally formed on the semiconductor substrate 20 in the fourteenth embodiment, the same effect can be obtained even if all or part of the circuit elements are integrally formed on the same semiconductor substrate. FIG.
FIG. 16 is a pattern diagram of a specific semiconductor substrate of the frequency mixer of this Example 15.

Diode 17 which is a circuit and a non-linear element
The components a and 17b are integrally formed on the semiconductor substrate 21.

According to the fifteenth embodiment, since the diode, which is a non-linear element, is integrally formed on the semiconductor substrate, these characteristics can be made uniform. Therefore, the efficiency of the frequency mixer is improved. The same applies when the non-linear element is the anti-parallel diode pair 5a, 5b.

Example 16. The frequency mixer shown in the first embodiment or the like can be used in the transmitter or the receiver. FIG. 23 is a block diagram of the transmitting apparatus according to the sixteenth embodiment. In the figure, 23 is a baseband circuit, 2
4 is a modulator, 25a and 25b are oscillators, 26 is a frequency mixer, 27 is a high-power amplifier, and 28 is an antenna.

Next, the operation will be described. The carrier wave generated by the oscillator 25a is modulated by the modulator 24 by the low frequency signal generated by the baseband circuit, and a modulated wave is generated. The generated modulated wave is frequency-mixed by the frequency mixer 26 with the harmonic of the local oscillation signal generated by the oscillator 25b, and a high frequency signal is generated. Here, the frequency mixer 26
If the image rejection type harmonic frequency mixer according to the first embodiment is used, the image signal is not output. Therefore, the image suppression filter becomes unnecessary.

Example 17 Although the above-described Example 16 describes the transmitting device, the same effect can be obtained even when used in the receiver. FIG. 24 is a block diagram of the receiving apparatus according to the seventeenth embodiment. In the figure, 29 is a low noise amplifier and 30 is a demodulator.

Example 18. In the above-described Embodiments 16 and 17, the transmitting device or the receiving device has been described, but the same effect can be obtained even when the transmitting device or the receiving device is used. FIG. 25 is a block diagram of the transmitting / receiving apparatus of the eighteenth embodiment. In the figure, 25 is an oscillator.

Next, the operation will be described. The local oscillation wave generated by the oscillator 25 is multiplied by the frequency mixer 26 and transmitted via the antenna 28.

On the other hand, the received signal received by the antenna 28 is frequency-mixed with the harmonic of the local oscillation wave generated by the oscillator 25 in the frequency mixer 26, and the generated intermediate frequency signal is input to the baseband circuit. To be done.

This transmission / reception apparatus combines the function of the transmission multiplier and the function of the reception frequency mixer into one frequency mixer 23.
(For example, the one shown in FIG. 16).
This method is particularly effective in a transmitter / receiver that performs homodyne detection, such as an FM-CW radar.

[0157]

As described above, according to the first and second aspects of the invention, the distribution phase difference of the high frequency signal and the distribution phase difference of the local oscillation signal by the hybrid coupler, the first transmission line and the second transmission line. The propagation phase difference of the high frequency signal and the propagation phase difference of the local oscillation signal due to the transmission line are combined to give a predetermined phase difference to the high frequency signal and the local oscillation signal. The second non-linear element performs frequency conversion processing on the basis of the high frequency signal and the local oscillation signal, and when the output signal of one of the intermediate frequency signal terminals is used as a reference, upper sidebands each having a phase difference of approximately ± 90 ° are provided. Since the signal and the lower sideband signal are output to the other intermediate signal terminal, it is possible to provide an image rejection mixer and a quadrature modulator having a simple configuration.

According to the third aspect of the invention, the hybrid coupler provides a predetermined distribution phase difference of the high frequency signal, and the first nonlinear element and the second nonlinear element generate the high frequency signal and the local oscillation signal. Frequency conversion processing is performed based on the output signal from one of the intermediate frequency signal terminals, and the upper sideband signal and the lower sideband signal, each of which is approximately ± 90 ° out of phase with each other, are output to the other intermediate signal terminal. Therefore, it is possible to provide an image rejection mixer and a quadrature modulator having a simple configuration.

According to the invention of claim 4, the first
Of the non-linear element and the second non-linear element, the short stub provided at the connection point connecting the sides of the non-hybrid coupler that are not connected to each other to the first non-linear element and the second non-linear element. Also, since the high frequency signal is short-circuited without affecting the local oscillation signal, it is possible to further avoid the interference between the high frequency signal and the local oscillation signal.

Further, according to the invention of claim 5, the hybrid coupler connected to the local oscillation signal terminal gives a predetermined distribution phase difference to the local oscillation signal, so that the image rejection mixer having a simple structure is provided. And a quadrature modulator can be provided.

Further, according to the invention of claim 6, since the power distributor connected to the high frequency signal terminal gives a predetermined phase difference to the high frequency signal, the image rejection mixer and the quadrature are simple in construction. A modulator can be provided.

According to the inventions of claims 7 and 8, the first non-linear element is provided between the local oscillation signal terminal and the first non-linear element and the second non-linear element, respectively.
Since the transmission line and the second transmission line give a predetermined phase difference to the local oscillation signal, it is possible to provide an image rejection mixer and a quadrature modulator having a simple configuration.

According to the invention of claim 9, the first
Of the transmission line or the second transmission line resonates at the local oscillation frequency to reduce the change in the phase characteristic near the resonance point, so that the frequency conversion characteristic of the frequency mixer is reduced. Is stable.

Further, according to the invention of claim 10, a predetermined propagation phase difference is given to the high frequency signal and the local oscillation signal by the first transmission line and the second transmission line, and the high frequency signal and the local oscillation signal are transmitted. The non-linear element 2 performs frequency conversion processing on the basis of the high frequency signal and the local oscillation signal, and when the output signal of one of the intermediate frequency signal terminals is used as a reference, the upper side band signal whose phase is approximately ± 90 ° different from each other. And the lower sideband signal is output to the other intermediate signal terminal,
An image rejection mixer and a quadrature modulator having a simple structure can be provided.

According to the eleventh aspect of the invention, the antiparallel diode pair operates as the first nonlinear element and the second nonlinear element without outputting the harmonic of the local oscillation signal to the outside. A high frequency signal and a harmonic of a local oscillation signal are mixed.

According to the twelfth aspect of the present invention, the diode operates as the first nonlinear element and the second nonlinear element, and outputs a harmonic of the local oscillation signal. Can be provided.

According to the invention of claim 13, the first intermediate frequency signal terminal and the second intermediate frequency signal terminal are connected to the plurality of terminals of one set, and the plurality of terminals of the other set. A hybrid coupler in which a third intermediate frequency signal terminal and a fourth intermediate frequency signal terminal are connected to a signal of a frequency band above the third intermediate frequency signal terminal and the fourth intermediate frequency signal terminal, or Since only one of the signals in the lower frequency band is output, an image rejection mixer having a simple structure can be provided.

According to the fourteenth aspect of the invention, by forming them on the same semiconductor substrate, the characteristics of the first nonlinear element and the second nonlinear element can be made uniform, and the frequency efficiency can be improved. It can be mixed well.

Further, according to the fifteenth aspect of the present invention, it is possible to provide a transmitter having a simple structure.

According to the sixteenth aspect of the present invention, it is possible to provide a receiver having a simple structure.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a frequency mixer according to a first embodiment.

FIG. 2 is an explanatory diagram of a down-conversion operation of the frequency mixer according to the first exemplary embodiment.

FIG. 3 is an explanatory diagram of an up-conversion operation of the frequency mixer according to the first exemplary embodiment.

FIG. 4 is a diagram for explaining the operating principle of the frequency mixer of the first embodiment.

FIG. 5 is a diagram for explaining the operating principle of the frequency mixer according to the first embodiment.

FIG. 6 is a functional block diagram of a frequency mixer according to a second embodiment.

FIG. 7 is a functional block diagram of a frequency mixer according to a third embodiment.

FIG. 8 is a functional block diagram of a frequency mixer according to a fourth embodiment.

FIG. 9 is a functional block diagram of a frequency mixer according to a fifth embodiment.

FIG. 10 is a functional block diagram of a frequency mixer according to a sixth embodiment.

FIG. 11 is a functional block diagram of a frequency mixer according to a sixth embodiment.

FIG. 12 is a functional block diagram of a frequency mixer according to a seventh embodiment.

FIG. 13 is an explanatory diagram of the operation of the frequency mixer of the seventh embodiment.

FIG. 14 is a functional block diagram of a frequency mixer according to an eighth embodiment.

FIG. 15 is a functional block diagram of a frequency mixer according to a ninth embodiment.

FIG. 16 is a functional block diagram of a frequency mixer of the tenth embodiment.

FIG. 17 is a functional block diagram of a quadrature modulator according to an eleventh embodiment.

FIG. 18 is a functional block diagram of a quadrature modulator according to a twelfth embodiment.

FIG. 19 is a functional block diagram of a quadrature modulator according to a thirteenth embodiment.

FIG. 20 is a circuit pattern diagram of the frequency mixer of the fourteenth embodiment.

FIG. 21 is a pattern diagram of an anti-parallel diode pair of Example 14.

FIG. 22 is a circuit pattern diagram of the frequency mixer of the fifteenth embodiment.

FIG. 23 is a functional block diagram of a transmitter according to a sixteenth embodiment.

FIG. 24 is a functional block diagram of a receiver according to the seventeenth embodiment.

FIG. 25 is a functional block diagram of a transmitter / receiver according to an eighteenth embodiment.

FIG. 26 is a sectional view of a conventional frequency mixer.

FIG. 27 is an explanatory diagram of a down conversion operation of a conventional frequency mixer.

FIG. 28 is an explanatory diagram of an up-conversion operation of a conventional frequency mixer.

FIG. 29 is a functional block diagram of a conventional frequency mixer.

[Explanation of symbols]

1 station signal terminal, 2 high frequency signal terminal, 3 90 degree hybrid coupler, 4 transmission line, 5 anti-parallel diode pair, 6 low pass filter, 7 intermediate frequency band 90 degree hybrid coupler, 8 intermediate frequency signal terminal, 9
Band pass filter, 10 open stubs, 11 short stubs, 12 power dividers, 13 termination resistors, 1
4 Coupling line with shorted ends, 15 Bandstop filter, 17 Diode, 18 Dielectric substrate, 19
Metal wire, 20 semiconductor substrate, 21 electrode, 22 via hole, 23 baseband circuit, 24 modulator 2
5 oscillator, 26 frequency mixer, 27 high output amplifier, 28 antenna, 29 low noise amplifier, 30 demodulator, 59 180 degree hybrid coupler

Claims (17)

[Claims] 1. A plurality of terminals isolated from each other are set, and a plurality of signals input to a plurality of terminals of one set are combined with different phase differences to a plurality of terminals of the other set. A hybrid coupler for outputting, a high frequency signal terminal and a local oscillation signal terminal respectively connected to a plurality of terminals of one set of the hybrid coupler, and a first terminal connected to a plurality of terminals of the other set of the hybrid coupler, respectively. Transmission line and second transmission line, and the first transmission line and the first transmission line respectively connected to the first transmission line and the second transmission line.
A non-linear element and a second non-linear element, and a first intermediate frequency signal terminal and a second intermediate frequency signal terminal respectively connected to the first non-linear element and the second non-linear element, The difference between the electrical length of the first transmission line and the electrical length of the second transmission line is approximately (m / 4 ± 1/8) · λ (however,
λ: a frequency mixer having a length corresponding to a wavelength of a local oscillation signal in each transmission line, m: 0 or a natural number). 2. The electrical length of the first transmission line and the second length
The difference from the electrical length of the transmission line is approximately (m / 2 ± 1/4)
A length corresponding to λ (where λ is the wavelength of the local oscillation signal in each transmission line, m: 0 or a natural number), and the harmonics of the local oscillation signal and the high frequency signal are frequency-mixed. 1. The frequency mixer according to 1. 3. A plurality of sets of terminals isolated from each other are provided, and a plurality of signals input to the plurality of terminals of one set are combined with different phase differences to obtain a plurality of terminals of the other set. A hybrid coupler for outputting, a high-frequency signal terminal connected to one of the terminals of one set of the hybrid coupler, a power distributor connected to the local oscillation signal terminal, and a plurality of terminals of the other set of the hybrid coupler. A first non-linear element and a second non-linear element respectively connected to the output terminal of the power divider, and the hybrid coupler of the first non-linear element and the second non-linear element Open stubs which are respectively provided at the connection parts of the first open circuit and open to the high frequency signal and short circuit to the local oscillation signal; Short stubs, which are respectively provided in the connection parts of the power divider of the non-linear element, are short-circuited to a high frequency signal and open to a local oscillation signal, and are connected to the first non-linear element and the second non-linear element, respectively. A first intermediate frequency signal terminal and a second
And a frequency mixer having an intermediate frequency signal terminal. 4. The first non-linear element and the second non-linear element are connected to each other on the non-connection side of the hybrid coupler, and a high frequency signal is short-circuited to this connection portion to open a local oscillation signal. 4. The frequency mixer according to claim 3, further comprising a short stub. 5. The frequency according to claim 3, further comprising a hybrid coupler connected to the local oscillation signal terminal, in place of the power distributor connected to the local oscillation signal terminal. Mixer. 6. The frequency mixer according to claim 3, further comprising a power distributor connected to the high-frequency signal terminal, instead of the hybrid connected to the high-frequency signal terminal. 7. A first non-linear element is provided between the local oscillation signal terminal and the first non-linear element and the second non-linear element, respectively.
And a second transmission line, the difference between the electrical length of the first transmission line and the electrical length of the second transmission line is approximately (m / 4 ± 1/8) · λ (however, ,
7. The frequency mixer according to claim 3, wherein λ is a wavelength corresponding to a wavelength of a local oscillation signal in each transmission line, m: 0 or a natural number. 8. A first circuit is provided between the local oscillation signal terminal and the first nonlinear element and the second nonlinear element, respectively.
And a second transmission line, and a difference between an electrical length of the first transmission line and an electrical length of the second transmission line is approximately (m / 2 ± 1/4) · λ (however, ,
7. The frequency mixer according to claim 3, wherein λ is a wavelength corresponding to a wavelength of a local oscillation signal in each transmission line, m: 0 or a natural number. 9. The method according to claim 1, wherein at least one of the first transmission line and the second transmission line is provided with a coupling line whose tips are coupled to each other. The frequency mixer according to claim 7 or claim 8. 10. A high-frequency signal terminal, and a first transmission line and a second transmission line, one ends of which are connected to the high-frequency signal terminal, respectively.
Transmission line, a first nonlinear element and a second nonlinear element connected to the other ends of the first transmission line and the second transmission line, respectively, and a local portion connected to the second nonlinear element. An oscillation signal terminal, a first intermediate frequency signal terminal and a second intermediate frequency signal terminal connected to the first non-linear element and the second non-linear element, respectively. The difference between the length and the electrical length of the second transmission line is set to a length corresponding to approximately m · λ (where λ is the wavelength of the local oscillation signal in the transmission line, m: 0 or a natural number), and The sum of the electrical length of the first transmission line and the electrical length of the second transmission line is approximately (n + 1/8)
.Lamda., Or roughly (n + 3/8) .lamda. (Where .lamda .:
A frequency mixer having a length corresponding to either the wavelength of a local oscillation signal in a transmission line, n: 0 or a natural number. 11. The frequency mixer according to claim 1, wherein each of the first nonlinear element and the second nonlinear element is an antiparallel diode pair. 12. The frequency mixer according to claim 1, wherein each of the first nonlinear element and the second nonlinear element is a diode. 13. The first intermediate frequency signal terminal and the second intermediate frequency signal terminal are connected to a plurality of terminals of one set, and the third intermediate frequency signal is connected to a plurality of terminals of the other set. The frequency mixer according to any one of claims 1 to 12, further comprising a hybrid coupler to which the terminal and the fourth intermediate frequency signal terminal are connected. 14. The frequency mixer according to claim 1, wherein the first nonlinear element and the second nonlinear element are formed on the same semiconductor substrate. 15. A transmitter comprising: a frequency mixer for converting a modulated intermediate frequency signal into a high frequency signal based on a local oscillation signal; and an antenna for receiving an output of the frequency mixer and radiating a radio wave into space. A transmitter, wherein the frequency mixer is the frequency mixer according to any one of claims 1 to 14. 16. A receiving device comprising: an antenna for receiving radio waves; and a frequency mixer for converting the output of the antenna into an intermediate frequency signal based on a local oscillation signal, wherein the frequency mixer is one of the claims. 14. A receiver, wherein the frequency mixer is any one of 14. 17. A transmission / reception device comprising a transmission device and a reception device, wherein the transmission device is the transmission device according to claim 15 and the reception device is the reception device according to claim 16.