# US 10,873,294 B2 · Balanced magnetoresistive frequency mixer

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- Number: US 10,873,294 B2
- Document ID: US10873294B2
- Status: Granted
- Kind: B2
- Application number: 16/326,342
- Filed: 2017-08-17
- Published: 2019-09-12
- Granted: 2020-12-22
- Earliest claimed: 2016-08-18
- Assignees: MultiDimension Technology Co., Ltd.
- Applicants: MultiDimension Technology Co., Ltd.
- Inventors: James Geza Deak; Zhimin Zhou
- Web page: https://patentgrep.com/patent/US10873294B2

## CPC

- H03D 7/14: Balanced arrangements
- G01R 33/0023: {Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration (G01R33/0017 takes precedence)}
- G01R 33/0094: {Sensor arrays}
- G01R 33/09: Magnetoresistive devices
- G01R 33/091: {Constructional adaptation of the sensor to specific applications}
- G01R 33/098: {comprising tunnel junctions, e.g. tunnel magnetoresistance sensors}
- H03D 2200/0074: using a resistive mixer or a passive mixer
- H03D: DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; demodulating pulses H03K9/00; transforming types of pulse modulation H03K11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B7/14; demodulators adapted for AC systems of digital information transmission H04L27/00; synchronous demodulators adapted for colour television H04N9/66)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A balanced magnetoresistive frequency mixer comprises a first spiral coil, a second spiral coil, a balanced magnetoresistive sensor bridge, and a magnetic shielding layer. The coils are located between the magnetic shielding layer and the sensor bridge. The sensor bridge comprises a magnetoresistive full bridge consisting of four bridge arms and a balancing bridge arm connected to the power supply end of the full bridge. The four bridge arms contain pairs located in a first sub region and a second sub region above or below the first spiral coil, the balancing arm is located in a third sub region above or below the second spiral coil, a first frequency signal is input into the first spiral coil, a second frequency signal is input into the second spiral coil, and a frequency-mixed signal is output from a signal output end of the full bridge.

## Claims

### Claim 1

A balanced magnetoresistive frequency mixer, comprising:
a spiral coil;
a balanced magnetoresistive sensor bridge; and
a magnetic shielding layer,
wherein the spiral coil is located between the magnetic shielding layer and the balanced magnetoresistive sensor bridge,
wherein the spiral coil comprises a first spiral coil and a second spiral coil, an upper surface or a lower surface of the first spiral coil has a first sub region and a second sub region in which the current flows in opposite directions, and an upper surface or a lower surface of the second spiral coil has a third sub region in which the current flows in one direction,
wherein the balanced magnetoresistive sensor bridge comprises a magnetoresistive full bridge and a balancing magnetoresistive arm connected to the magnetoresistive full bridge, the magnetoresistive full bridge consists of four magnetoresistive bridge arms, two of which are located in the first sub region and the other two are located in the second sub region, and the balancing magnetoresistive arm is located in the third sub region,
wherein a first frequency signal is input into the first spiral coil (40), a second frequency signal is input into the second spiral coil, and a frequency-mixed signal is output from a signal output end of the magnetoresistive full bridge, wherein the output frequency of the frequency-mixed signal is a sum of or a difference between the frequencies of the first frequency signal and the second frequency signal.

### Claim 2 (depends on 1)

The balanced magnetoresistive frequency mixer according to claim 1, wherein
there is one balancing magnetoresistive arm that is connected to a power supply output end or an input end of the magnetoresistive full bridge; or
there are two balancing magnetoresistive arms that are connected to a power supply output end and an input end of the magnetoresistive full bridge, respectively.

### Claim 3 (depends on 2)

The balanced magnetoresistive frequency mixer according to claim 2, wherein the magnetoresistive bridge arms and the balancing magnetoresistive arm separately comprise M*N arrayed magnetic tunnel junctions, the magnetic tunnel junctions in each column are connected in series to form a magnetic tunnel junction cell string, the magnetic tunnel junction cell strings are connected in series, in parallel, or in a series/parallel manner to form a two-port structure, N denotes a column of an arrayed structure, M denotes a row of the arrayed structure, and N and M are respectively positive integers greater than or equal to 1.

### Claim 4 (depends on 3)

The balanced magnetoresistive frequency mixer according to claim 3, wherein sensitive axes of the magnetic tunnel junctions in the magnetoresistive bridge arms are all perpendicular to a current direction of the first spiral coi, sensitive axes of the magnetic tunnel junctions in the balancing magnetoresistive arm are all perpendicular to a current direction of the second spiral coil, and distribution characteristics of sensitive axial magnetic fields of the magnetic tunnel junctions in the first sub region are opposite to those of the magnetic tunnel junctions in the second sub region.

### Claim 5 (depends on 3)

The balanced magnetoresistive frequency mixer according to claim 3, wherein the magnetic tunnel junctions in the first sub region and the magnetic tunnel junctions in the second sub region are connected in identical structures and arranged symmetrically.

### Claim 6 (depends on 3)

The balanced magnetoresistive frequency mixer according to claim 3, wherein
resistances of the magnetic tunnel junctions in the first sub region and the second sub region are respectively linear to sensitive axial magnetic fields of the magnetic tunnel junctions generated by the first spiral coil; and
resistances of the magnetic tunnel junctions in the third sub region are linear to sensitive axial magnetic fields of the magnetic tunnel junctions generated by the second spiral coil.

### Claim 7 (depends on 3)

The balanced magnetoresistive frequency mixer according to claim 3, wherein the magnetic tunnel junctions in the first sub region and the second sub region are perpendicular or parallel to the current direction of the first spiral coil, and the magnetic tunnel junctions in the third sub region are perpendicular or parallel to the current direction of the second spiral coil.

### Claim 8 (depends on 1)

The balanced magnetoresistive frequency mixer according to claim 1, wherein the first frequency signal is connected to the first spiral coil actively or passively, the second frequency signal is connected to the second spiral coil passively or actively, and the frequency-mixed signal is connected to the signal output end of the balanced magnetoresistive sensor bridge passively or actively.

### Claim 9 (depends on 1)

The balanced magnetoresistive frequency mixer according to claim 1, wherein the spiral coil is a coil of a high-conductivity metal material comprising one or more of copper, gold, silver, aluminum, and tantalum, and the magnetic shielding layer is a layer of a high-permeability ferromagnetic alloy comprising one or more of NiFe, CoFeSiB, CoZrNb, CoFeB, FeSiB, and FeSiBNbCu.

### Claim 10 (depends on 1)

The balanced magnetoresistive frequency mixer according to claim 1, wherein the thickness of the spiral coil is 1-20 μm, the width of the spiral coil is 5-40 μm, a spacing between two adjacent spiral coils is 10-100 μm, and the thickness of the magnetic shielding layer is 1-20 μm.