# US 9,438,169 B2 · Mixer

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- Number: US 9,438,169 B2
- Document ID: US9438169B2
- Status: Granted
- Kind: B2
- Application number: 14/563,407
- Filed: 2014-12-08
- Published: 2015-05-28
- Granted: 2016-09-06
- Earliest claimed: 2012-10-31
- Assignees: Qualcomm Technologies International, Ltd.
- Applicants: Qualcomm Technologies International, Ltd.
- Inventors: James Collier; Tim Newton
- Web page: https://patentgrep.com/patent/US9438169B2

## CPC

- H03D 7/1483: {comprising components for selecting a particular frequency component of the output}
- H03D 7/1458: {Double balanced arrangements, i.e. where both input signals are differential}
- H03D 7/1466: {Passive mixer arrangements}
- H03D 7/165: {at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature (combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002)}
- H03H 7/01: Frequency selective two-port networks
- H03H 9/02259: {Driving or detection means}
- H04B 1/04: Circuits
- H04B 1/26: for superheterodyne receivers (multiple frequency-changing H03D7/16)
- H03H 2007/006: {MEMS}
- H04B 2001/0491: {with frequency synthesizers, frequency converters or modulators}
- 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)
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H04B: TRANSMISSION

## Abstract

A frequency shifter configured to shift the frequency of a signal, the frequency shifter comprising: a resonant structure configured to mechanically resonate at a first frequency; and a plurality of capacitors, each capacitor having a variable plate separation distance, wherein the resonant structure is configured to cause the plate separation distance of each capacitor to oscillate so as to cause the frequency of the signal to shift by the first frequency.

## Claims

### Claim 1

A receiver comprising:
an input for receiving an incoming signal;
a first input buffer arranged to buffer the incoming signal and provide a first buffered signal and an inverse first buffered signal;
a second input buffer arranged to buffer the incoming signal and provide a second buffered signal and an inverse second buffered signal;
a first capacitor having a first plate coupled to the first buffered signal;
a second capacitor having a first plate coupled to the inverse first buffered signal and a second plate coupled to a second plate of the first capacitor;
a third capacitor having a first plate coupled to the second buffered signal;
a fourth capacitor having a first plate coupled to the inverse second buffered signal and a second plate coupled to a second plate of the third capacitor; and
a resonant structure configured to mechanically oscillate at a first frequency, wherein the resonant structure is configured so that the oscillations of the resonant structure cause oscillations in the capacitances of the first, second, third, and fourth capacitors.

### Claim 2 (depends on 1)

A receiver according to claim 1, further comprising:
a first output buffer coupled to the second plate of the first capacitor to produce an in-phase output; and
a second output buffer coupled to the second plate of the third capacitor to produce a quadrature output.

### Claim 3 (depends on 2)

A receiver according to claim 2, wherein the first output buffer is a current-to-voltage converter and the second output buffer is a current-to-voltage converter.

### Claim 4 (depends on 1)

A receiver according to claim 1, wherein the oscillation of the capacitance of the first capacitor is out of phase by 180 degrees with respect to oscillation of the capacitance of the second capacitor, the oscillation of the capacitance of the third capacitor is out of phase by 180 degrees with respect to oscillation of the capacitance of the fourth capacitor, and the oscillation of the capacitance of the first capacitor is out of phase by 90 degrees with respect to oscillation of the capacitance of the third capacitor.

### Claim 5 (depends on 1)

A receiver according to claim 1, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in separations of the plates of the first, second, third, and fourth capacitors.

### Claim 6 (depends on 1)

A mixer according to claim 1, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in an overlap of the plates of the first, second, third, and fourth capacitors.

### Claim 7 (depends on 1)

A mixer according to claim 1, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in a dielectric constant of the first, second, third, and fourth capacitors.

### Claim 8 (depends on 7)

A mixer according to claim 7, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations of dielectric materials in and out of gaps between the plates of the first, second, third, and fourth capacitors.

### Claim 9

A mixer comprising:
an input buffer arranged to buffer an incoming signal and provide a first buffered signal and an inverse first buffered signal;
a first capacitor includes a first plate coupled to the first buffered signal;
a second capacitor includes a first plate coupled to the inverse first buffered signal and a second plate coupled to a second plate of the first capacitor; and
a resonant structure configured to mechanically oscillate at a first frequency, wherein the resonant structure is configured so that the oscillations of the resonant structure cause oscillations in the capacitance of the first capacitor and oscillations in the capacitance of the second capacitor.

### Claim 10 (depends on 9)

A mixer according to claim 9, further comprising a driver configured to drive the resonant structure.

### Claim 11 (depends on 9)

A mixer according to claim 9, wherein the oscillation of the capacitance of the first capacitor is out of phase by 180 degrees with the oscillation of the capacitance of the second capacitor.

### Claim 12 (depends on 11)

A mixer according to claim 11, further comprising an output buffer having an input coupled to the second plate of the first capacitor and converted to produce a mixer output as a voltage signal.

### Claim 13 (depends on 12)

A transmitter comprising a mixer according to claim 12, the transmitter being arranged to transmit a signal including the mixer output from the output buffer.

### Claim 14 (depends on 9)

A mixer according to claim 9, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in a separation of the plates of the first capacitor and oscillations in a separation of the plates the second capacitor.

### Claim 15 (depends on 9)

A mixer according to claim 9, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in an overlap of the plates of the first capacitor and oscillations in an overlap of the plates the second capacitor.

### Claim 16 (depends on 9)

A mixer according to claim 9, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations in a dielectric constant of the first capacitor and oscillations in a dielectric constant of the second capacitor.

### Claim 17 (depends on 16)

A mixer according to claim 16, wherein the resonant structure is further configured so that the oscillations of the resonant structure cause oscillations of a dielectric material in and out of a gap between the plates of the first capacitor and oscillations of a dielectric material in and out of a gap between the plates of the second capacitor.