JPWO2018101437A1 - Variable phase multiplier - Google Patents

Abstract

The phase variable type multiplier of the present invention includes a multiplier that multiplies the frequency fref of the reference signal by n times, and a magnetoresistive element that outputs a high frequency having a pre-synchronization frequency fMR that is equal to or synchronizable with the frequency f after synchronization. And a bias voltage applying mechanism for changing the frequency of the pre-synchronization frequency fMR. By multiplying the frequency (1 / n) f of (1 / n) times (n is a natural number of 2 or more) or the frequency (1 / n) f of the reference signal frequency fref by injection locking to the magnetoresistive element, a multiplier is obtained. Outputs a first high-frequency output having a frequency f that is n times the frequency fref of the reference signal, and outputs a second high-frequency output having a synchronized frequency f from the magnetoresistive element before being synchronized by the bias voltage application mechanism. By changing the frequency fMR, the phase of the second high frequency output can be changed with respect to the phase of the first high frequency output.

Description

  The present invention generally relates to frequency multipliers, and more particularly to a phase variable frequency multiplier capable of changing the phase of a high frequency.

  In recent years, communication technology using high frequencies (about 100 MHz to 300 GHz) including microwaves (about 1 GHz to 300 GHz) has become more and more important, and the technology is widely used in wireless communication in mobile phones, wireless LANs, satellite broadcasting, radars, etc. in use. In wireless communication, information is transmitted and received by replacing a signal to be transmitted with high-frequency amplitude, frequency, or phase modulation.

  As the amount of communication increases, the frequency of radio communication signals is increasing, and the importance of a multiplier (frequency multiplier) that increases the frequency of a high-frequency oscillator to an integral multiple (2 times, 3 times,...). It is also increasing year by year. On the other hand, in recent years, it has been desired to provide high-frequency signal directivity in wireless communication. In order to give high-frequency signal directivity, it is necessary to arbitrarily change the phase of the high-frequency signal. For example, a phased array radar in which the radar has directivity.

  There is also an increasing demand for smaller and cheaper high-frequency oscillators, including those used in frequency multipliers. With the aim of reducing the size, for example, a high-frequency oscillator using a magnetoresistive element (hereinafter referred to as “MR element”) exemplified in Patent Document 1 has been proposed. In the high frequency oscillator using the MR element, there is a problem that the output frequency is not stable (the peak width is wide) similarly to the high frequency oscillator using the conventional resonator (VCO). In order to solve this problem, a technique called injection locking has been proposed (Non-Patent Document 1).

  In injection locking, by adding a reference signal source and injecting a stable (narrow peak width) high frequency output from the reference signal source into the MR element, the output frequency of the MR element is stabilized (the peak width is narrowed). Is. This utilizes the phenomenon that the output frequency of the MR element becomes the same as the output frequency of the reference signal when the frequency difference between the frequency of the reference signal and the pre-synchronization frequency of the MR element is smaller than a predetermined bandwidth. . In this case, not only the frequency becomes the same, but also the frequency follows and synchronizes accurately, so that the output frequency of the MR element can be stabilized.

JP 2006-295908 A

W. H. Rippard, MR. Pufall, S. Kaka, T. J. Silva, S. E. Russek, J. A. Katine, Physical Review Letters 95 (2005) 067203

  An object of the present invention is to provide a phase variable frequency multiplier (hereinafter referred to as “phase variable multiplier”) that can change the phase of a high frequency by using an MR element as a high frequency oscillator and utilizing injection locking. Is to provide.

The above injection locking not only improves the stability of the output frequency of the MR element (decreases the peak width), but can also arbitrarily control the phase difference Δφ which is the above-mentioned problem. Specifically, the phase difference Δφ between the frequency f _{ref of the} reference signal and the pre-synchronization frequency f _MR output by the MR element is

Δφ = arcsin {(f _MR −f _ref ) / W} (1)

There is a relationship. arcsin is an arc sine function. Since the pre-synchronization frequency f _MR of the MR element can be varied (controlled) by the applied voltage, magnetic field, temperature, etc., each frequency of the output of the reference signal and the output from the MR element is f by injection locking. Only the phase difference Δφ can be changed with the predetermined value (fixed value). However, the phase difference Δφ between the two output high frequencies f is not necessarily the same as Δφ. This is because the phase is shifted by passing through the signal line. Here, it is only necessary to explain that the phase difference Δφ between the two high frequencies to be output can be changed from the above equation (1).

On the other hand, when injection locking occurs, when the frequency after synchronization is f, the output frequency f _ref of the reference signal is equal to f, and the output (resonance) frequency f _{MR of the MR} element is equal to f. This occurs not only when the reference signal frequency f _ref is equal to or “nearly equal” n times f (n is a natural number greater than or equal to 2). The bandwidth W at which synchronization can occur tends to increase when the high-frequency output of the reference signal is increased. Even if “substantially equal” is satisfied, synchronization is possible within 40% of f, preferably within 30%. Therefore, in this specification, the expression “synchronizable” is used instead of “substantially equal”.

The inventors of the present invention have made the present invention paying attention to this n times. In the present invention, when the frequency after synchronization is f, injection locking is performed using a frequency f _ref of the reference signal that is equal to 1 / n times (f / n) instead of one time as usual. I decided to do it. Then, the reference signal is sent to the output separately from the MR element system, and at that time, the frequency is returned to n times by the multiplier. In general, a multiplier is a device that increases the frequency by 2 times, 3 times,..., But in the present invention, a device that reduces the frequency by 1/2, 1/3 times,. Call. By doing so, the high frequency having the frequency f multiplied by the multiplier is output (output 1), while the high frequency having the frequency f synchronized with the reference signal is output (output 2) from the MR element system. Can do. At this time, since the pre-synchronization frequency f _MR of the MR element can be varied, the phase of the output 1 can be changed while the phase of the output 1 is stabilized. As a result, the MR element can be changed to a predetermined (can be changed). A phase difference Δφ can be obtained. This is an outline (principle) of phase variation of the phase variable type multiplier (n-times multiplier) of the present invention.

Based on the above-described principle, the phase variable multiplier according to one aspect of the present invention includes a multiplier that multiplies the frequency f _{ref of the} reference signal by n times, and a pre-synchronization frequency f that is equal to or synchronizable with the frequency f after synchronization. A magnetoresistive element that outputs a high frequency having _MR and a bias voltage application mechanism for changing the frequency of the pre-synchronization frequency f _MR are provided. The frequency (1 / n) f, which is 1 / n times the frequency f after synchronization (n is a natural number equal to or greater than 2) or the inverse thereof, is injected and synchronized with the magnetoresistive element as the frequency _fref of the reference signal, thereby being multiplied. A first high-frequency output having a frequency f that is n times the frequency f _ref of the reference signal is output from the device, and a second high-frequency output having a synchronized frequency f is output from the magnetoresistive element. Furthermore, the phase of the second high-frequency output can be changed with respect to the phase of the first high-frequency output by changing the pre-synchronization frequency f _MR by the bias voltage application mechanism.

It is a figure which shows the structure of the phase variable type | mold multiplier of one Embodiment of this invention. It is a figure which shows the structure of the phase variable type | mold multiplier of other one Embodiment of this invention. It is a figure which shows the structure of MR element of one Embodiment of this invention. It is a figure which shows the structure (input / output) of the divider | distributor of one Embodiment of this invention. It is a figure which shows the structure (input / output) of the attenuator of one Embodiment of this invention. It is a figure which shows the structure (input / output) of the directional coupler of one Embodiment of this invention. It is a figure which shows the flow of the signal in the phase variable type multiplier of one Embodiment of this invention. It is a figure which shows the change of the output spectrum of MR element with respect to the bias voltage of one Embodiment of this invention. It is a figure which shows the change of the frequency of MR element with respect to the bias voltage of one Embodiment of this invention. It is a figure which shows the high frequency spectrum of 2 outputs of the phase variable type | mold multiplier of one Embodiment of this invention. It is a figure which shows the bias voltage dependence of the frequency of 2 outputs of the phase variable type | mold multiplier of one Embodiment of this invention. It is a figure which shows the bias voltage dependence of the phase difference of 2 outputs of the phase variable type | mold multiplier of one Embodiment of this invention.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a phase variable multiplier according to an embodiment of the present invention. 1 includes a multiplier 1, an MR element 2, a bias voltage application mechanism 3, a first signal line 4, an output signal line 5, a coupling means 6, a bias tee (Bias Tee). ) 7 is included. A multiplier 1 that increases the frequency f _ref (= f / n) of an input reference signal by n times (a natural number of 2 or more) is also called a frequency multiplier. Specifically, a circuit using a class B or class C amplifier, a variable capacitance diode, and a band pass filter is used as the multiplier 1. Both the class B and class C amplifiers used as a multiplier are amplified when a reference signal (clean sine wave = fundamental wave) is input, but the output signal is distorted, and the output signal has harmonics ( Have a frequency that is an integer multiple of the frequency of the reference signal). Therefore, a filter is provided on the output side of the amplifier so that only harmonics having a desired integer multiple frequency are passed and the others are cut. Thus, it functions as a multiplier. The multiplier 1 may reduce the frequency f _ref (= f / n) of the input reference signal by n times (the reciprocal of a natural number of 2 or more). What is reduced is generally called a frequency divider, but in the present invention, it is called a “multiplier” for convenience of explanation. Specific examples of such a multiplier (generally a frequency divider) include those using a flip-flop circuit.

The MR element 2 oscillates at a frequency f _MR and outputs a high frequency. MR elements are classified into a horizontal type, a vertical type and a magnetic vortex type depending on the direction of magnetization, and any of them can be used. As illustrated in FIG. 3, the MR element basically includes a free layer, a nonmagnetic layer, and a fixed layer. The free layer and the fixed layer are made of a ferromagnetic material and are made of, for example, FeB or CoFeB. The nonmagnetic layer is made of a nonmagnetic metal or an insulator, and is made of, for example, Cu, Ag, Cr or the like, or an oxide, nitride, halide or the like of Mg, Al, Si, Ca, Li or the like. In the MR element 2, when a direct current is passed from the free layer to the fixed layer or vice versa, the electron spin of the free layer is excited by the spin torque of the direct current, and the relative angle between the magnetization of the free layer and the fixed layer is the time. Resonates against. This resonance is converted into a high-frequency signal through the tunnel magnetoresistive effect or the giant magnetoresistive effect, and the MR element oscillates a high frequency (sometimes referred to as “output” in the present invention).

The bias voltage application mechanism 3 is required for operating the MR element 2 and changing the oscillation (output) frequency f _MR . By inputting a bias voltage (DC), the resonance frequency of the MR element changes, and the output frequency f _MR (and therefore the phase difference Δφ) can be changed. The bias voltage application mechanism generally includes a bias voltage source and a signal line for voltage application. Since the MR element generally has a resistance of about 10 to 1 kΩ, it is necessary to apply a voltage of about 100 to 700 mV. Therefore, a DC power supply with a maximum output of 1 V and about 100 mA is desirable as the bias voltage source.

The first signal line 4 receives a reference signal having a frequency f _ref (= f / n) and guides it to the multiplier 3. In other words, the reference signal source (details will be described later) and the multiplier 3 are electrically connected. It is made of a conductive material such as gold, silver, copper, or aluminum. If a semiconductor manufacturing technique is used, it can be formed with a line width of the nm to μm level. However, in the laboratory, it is convenient to use a copper stranded wire or a coaxial cable. Although expressed as “line”, it is conceptual and may have a finite size.

  The output signal line 5 electrically connects the output terminal of the MR element 2 and the output terminal of the output 2 and, like the first signal line, a conductive material such as gold, silver, copper, aluminum or the like. Made with. In the laboratory, it is convenient to use a copper stranded wire or a coaxial cable. Also in this case, it is expressed as “line”, but it is conceptual and may have a finite size.

The coupling means 6 guides a reference signal having a frequency f _ref (= f / n) to the MR element 2. In other words, the coupling means 6 electrically connects a reference signal source (described later in detail) and the MR element 2. The first signal line 4 is made of a conductive material such as gold, silver, copper, or aluminum. Although FIG. 1 shows a line connecting the first signal line 4 and the output signal line 5, this is also conceptual and may have a finite size depending on the case.

  The bias tee (Bias Tee) 7 generally includes a capacitor and a coil, and is used to superimpose a DC signal (here, a bias voltage) on an AC signal. If a DC signal may be applied to the reference signal side, output 1 and output 2, the bias tee 7 may not be used and a bias voltage may be applied directly to the MR element 2.

  FIG. 2 is a diagram showing the configuration of a phase variable multiplier according to another embodiment of the present invention. 2, the reference signal source 12, the divider 9, the attenuator 10, and the directional coupler 12 constituting the coupling means 6, compared to the phase variable type multiplier of the embodiment of FIG. An amplifier 8 and a filter 14 on the output signal line 5 and a magnetic field applying mechanism 13 to the MR element 2 are further added. Only these added means will be described below. The other configurations that are the same as those in FIG. 1 have already been described above, and a description thereof will be omitted.

Reference signal source 12 outputs a reference signal having a high frequency of f _ref. The frequency f _{ref of the} reference signal is selected to be equal to 1 / n times the post-synchronization frequency f (n is a natural number of 2 or more or its inverse). n is preferably 2 to 12 or 1/12 to 1/2. In particular, n is preferably 2. As the reference signal source 12, for example, a voltage controlled oscillator (VCO), a phase locked loop (PLL) oscillator, a crystal (LC) oscillator, or the like is used.

  The distributor 9 uses, for example, a resistance type three-port distributor shown in FIG. 4, and distributes the reference signal into two signals. Although it is close to a simple coupling point, the signal input from each port is divided into two and output to other ports. There is no signal directionality. The signal of port3 → port1 and the signal of port1 → port3 have the same output signal strength when coming out from port2. Since it is used for signal synthesis in addition to distribution, it is sometimes called a “distributor / synthesizer”.

  The attenuator 10 is a device that attenuates a high-frequency signal shown in FIG. 5, for example. There is no signal directionality. The signal of port2 → port1 and the signal of port1 → port2 have the same output signal strength. In the configuration of FIG. 2, the MR element 2 is used because an excessive high frequency signal is not injected. The breakdown voltage of the MR element 2 is generally about 200 mV to 1 V. For this reason, if the injection locking input exceeds the above voltage, element destruction occurs. Therefore, it is necessary to adjust the input to the MR element 2 using an attenuator.

  The directional coupler 12 is greatly different from a simple coupling point. For example, as shown in FIG. 6, a signal input from port 1 is output to port 3 with little attenuation. A signal of about −14 dB of the signal input from port 1 flows into port 2 (just a little). The signal that enters from port 3 is output to port 1 with little attenuation. A signal of about −28 dB (almost zero) of the signal input from port 3 flows to port 2. For this reason, since the directionality of a signal becomes important, it is called a directional coupler.

  The amplifier 8 is provided in order to amplify the signal intensity (amplitude) of the high frequency signal (fundamental wave = before synchronization) output from the MR element (resonance) as very low as about 10 mV (rms). Note that rms (root mean square) means an effective value. As the amplifier 8, a transistor or a circuit using the transistor is used as the amplifier.

The filter 14 is appropriately provided with filters when unnecessary signals are input to the outputs 1 and 2 and others. In the configuration of FIG. 2, a filter 14 is inserted after the amplifier 8 so that the output 2 outputs only the signal (frequency f _MR ) from the MR element 2. This filter is not an actual actual device but is artificially inserted by signal analysis processing. The filter includes a reflection type and an attenuation type. Here, the attenuation type is desirable.

The magnetic field applying mechanism 13 to the MR element 2 is additionally provided when the MR element 2 is operated by inputting a bias voltage (DC) and it is desired to change the output frequency f _MR (and therefore the phase difference Δφ). Depending on the magnetic field, the MR element 2 can be easily operated, and the oscillation frequency f _MR can be changed. The magnetic field application mechanism 13 may be a permanent magnet, but is preferably an electromagnet that can easily change the magnetic field strength. An electromagnet is usually a magnet that temporarily generates a magnetic force by winding a coil around a magnetic material core and energizing it. Here, however, there is no magnetic material (core) and a magnetic field created simply by an electric current is applied. It can also be used as a mechanism.

The phase variable multiplier of one embodiment of the present invention shown in FIG. 2 was mounted using the following devices, and the operation was confirmed.
Multiplier 1: As a multiplier with n = 2, a wideband multiplier ZX90-2-36 + manufactured by Mini-Circuits Inc. having a conversion loss index of about 11 dB and a band of 1.7 GHz to 5.4 GHz was used.
MR element 2: the free layer is an FeB layer (thickness 2 nm), the nonmagnetic layer is an MgO layer (thickness 1 nm), and the fixed layer is CoFeB (thickness 3 nm) / Ru (thickness 0.86 nm) / A multilayer film made of CoFe (thickness 2.5 nm) / PtMn (thickness 15 nm) was used.
Bias voltage application mechanism 3: A Precision Source Measure Unit B2912A manufactured by Keysight Technologies with a minimum power source resolution of 100 nV was used.
Bias-Tee 7: A broadband Bias-Tee 11612A manufactured by Keysight Technologies with an insertion loss index of about 0.8 dB and a band of 45 MHz to 26.5 GHz was used.

Amplifier 8: A wideband amplifier ZVA-183W + manufactured by Mini-Circuits with an amplification factor of about 27 dB, a noise figure of 2.4 dB, and a band of 100 MHz to 18 GHz in the vicinity of the output frequency (6.7 GHz) of the MR element 2 was used. .
Divider 9: A wide-band resistive divider ZFRSC-183 + manufactured by Mini-Circuits with an insertion loss index of about 7 dB and a band of DC-18 GHz was used.
Attenuator 10: A broadband attenuator BW-K20-2W44 ++ manufactured by Mini-Circuits Inc. having an insertion loss index of about 20 dB and a band of DC-40 GHz was used.
Directional coupler 11: A coaxial directional coupler 87301D manufactured by Keysight Technologies was used.
Reference signal source 12: An analog signal generator E8257D manufactured by Keysight Technologies Inc. having an output power of −135 dBm to +21 dBm and a band of 250 kHz to 40 GHz was used.
Filter 14: A 10-stage Butterworth high-pass filter with a cutoff frequency of 8 GHz was used.

  FIG. 7 shows a signal flow in the embodiment of the phase variable multiplier using each of the above devices. A reference signal having a frequency f / 2 (3.37 GHz) of 16 dBm is output from the reference signal source 12 and is equally distributed to two 10 dBm signals by the distributor 9. One of the 10 dBm signals distributed by the distributor 9 is input to the multiplier 1. The multiplier 1 operates and outputs a high-frequency signal having a frequency f (6.74 GHz) of 0 dBm to the output 1. Further, the other 10 dBm signal distributed by the distributor 9 passes through the attenuator 10, the directional coupler 11, and the Bias-tee 7 and is injected into the MR element 2 after the signal intensity is attenuated to about −10 dBm. Injection locking occurs.

  The MR element 2 outputs a high frequency signal having a frequency f (6.74 GHz) of about −30 dBm by the bias voltage from the bias voltage application mechanism 3. The high frequency signal of the MR element 2 is amplified through the Bias-tee 7, the directional coupler 11, the amplifier 8, and the high-pass filter 14, and a high frequency signal having a frequency f (6.74 GHz) of −17 dBm is output to the output 2. At this time, of the other 10 dBm signal distributed by the distributor 9, the signal branched by the directional coupler 11 through the attenuator 10 is amplified through the amplifier 8, and the frequency f / 2 of -11 dBm is obtained. In order to prevent a high frequency signal (3.37 GHz) from being output to the output 2 through the amplifier 8, the high-pass filter 14 attenuates the high frequency signal having a frequency f / 2 (3.37 GHz) of -11 dBm. . The signal of the MR element 2 passes through the directional coupler 11, the attenuator 10, and the distributor 9, and a high frequency signal of −56 dBm frequency f (6.74 GHz) is input to the multiplier 1. The signal is attenuated here and does not contribute to the output because the power is not reached.

FIG. 8 shows the results of measuring the output spectrum (especially the frequency and spectrum intensity of the output frequency f _MR ) in the predetermined bias voltage range (200 to 230 mV around 215 mV) for the MR element 2 used as an example. Show. At this time, a magnetic field is applied to the MR element 2 using an electromagnet as the magnetic field applying mechanism 13. The magnitude of the magnetic field was 3 kOe, and the magnetic field was applied in a direction inclined at an elevation angle of 67 degrees with respect to the film surface and 120 degrees with respect to the fixed layer magnetization. The MR element 2 exhibits a unimodal output spectrum in the bias voltage range of 200 to 230 mV. The integrated output of the unimodal output spectrum has not changed.

FIG. 9 is obtained from the result of FIG. 8, and shows a change in the output frequency f _MR (before synchronization) of the MR element 2 in a predetermined bias voltage range (200 to 230 mV around 215 mV). . As a result, it was shown that the output frequency f _MR changes substantially monotonically (about 6.78 to about 6.68 GHz) around 6.72 GHz in the bias voltage range of 200 mV to 230 mV.

  FIG. 10 shows the result of operating the example of the phase variable multiplier according to the embodiment of the present invention shown in FIG. 2 using the MR element 2 having the characteristics shown in FIGS. The peak widths of the output spectrum of output 1 of (a) and output 2 of (b) were both as small as 6 kHz. In this case, as already described above, the reference signal having the frequency of 3.37 GHz (f / 2) from the reference signal source 12 is injection-locked to the MR element and phase-locked to the output frequency f = 6.74 GHz. For comparison, when the high frequency was output only by the MR element 2 without outputting the reference signal from the output 1 (comparative example), the peak width of the output 2 was as large as about 3 MHz.

FIG. 11 shows frequency changes of the output 1 from the multiplier 1 and the output 2 from the MR element 2 in a predetermined bias voltage range (around 209 mV). Since the output frequency f _MR (fundamental wave = before synchronization) of the MR element 2 is synchronized with the reference signal by injection locking, the output 2 is a doubled signal (frequency f / 2) of the reference signal (frequency f / 2) regardless of the bias voltage. ) And the same frequency (6.74 GHz).

  FIG. 12 shows changes in the phase difference Δφ between the output 1 (frequency f) from the multiplier 1 and the output 2 (frequency f) from the MR element in a predetermined bias voltage range (around 209 mV). The phase difference Δφ between the outputs 1 and 2 changed from −π / 2 to + π / 2 with respect to the change in the bias voltage applied to the MR element 2. Thus, it was confirmed that the phase difference Δφ between the outputs 1 and 2 can be changed without changing the frequency f between the outputs 1 and 2 by changing the bias voltage.

  Embodiments of the present invention have been described with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the present invention can be implemented in variously modified, modified, and modified forms based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

  The phase variable type multiplier of the present invention can output a high frequency (first output = output 1) having a stable frequency (narrow peak width) synchronized after the multiplication (first output = output 1) and the first output (= output). It is possible to change the phase of the second output (= output 2) with respect to the phase of 1). This phase variable type multiplier is small and inexpensive by using an MR element. Therefore, the multiplier of the present invention can be used for various communication devices.

1: Multiplier 2: MR element 3: Bias voltage application mechanism 4: First signal line 5: Output signal line 6: Coupling means 7: Bias Tee
8: Amplifier 9: Divider 10: Attenuator 11: Directional coupler 12: Reference signal source 13: Magnetic field applying mechanism 14: Filter (high-pass filter)

Claims (7)

A multiplier for multiplying the frequency f _{ref of the} reference signal by n times;
A magnetoresistive element that outputs a high frequency having a pre-synchronization frequency f _MR that is equal to or synchronized with the frequency f after synchronization;
A bias voltage application mechanism for changing the frequency of the pre-synchronization frequency f _MR ,
The reference signal from the multiplier is obtained by injection-synchronizing the frequency (1 / n) f of the frequency f after synchronization (1 / n) times (n is a natural number of 2 or more or the inverse thereof) to the magnetoresistive element as a reference signal. A first high-frequency output having a frequency f which is n times the frequency f _ref of the first frequency f is output, and a second high-frequency output having a frequency f synchronized with the magnetoresistive element is output.
A phase variable type multiplier capable of changing the phase of the second high-frequency output with respect to the phase of the first high-frequency output by changing the pre-synchronization frequency f _MR by the bias voltage application mechanism. Further comprising the magnetoresistive element a magnetic field applying mechanism for applying a magnetic field, characterized by varying the frequency of the synchronizing frequency before f _MR by changing the magnetic field, the phase variable multiplier according to claim 1.   2. The variable phase multiplier according to claim 1, wherein n is two.   The phase variable type according to claim 2, further comprising: a reference signal source that outputs the reference signal; and a distributor that distributes the reference signal from the reference signal source toward the multiplier and the magnetoresistive element. Multiplier.   An attenuator that attenuates the reference signal after distribution between the distributor and the magnetoresistive element; and the attenuated reference signal is directed to the output stage of the magnetoresistive element and the second high-frequency output. The phase variable multiplier according to claim 4, further comprising a branching directional coupler. An amplifier and a filter are further provided between the directional coupler and the output stage of the second high-frequency output;
The phase variable multiplier according to claim 5, wherein the directional coupler branches the second high-frequency output output from the magnetoresistive element toward the amplifier.   The phase variable multiplier according to claim 6, further comprising a bias tee between the magnetoresistive element and the bias voltage application mechanism.

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