# US 10,374,675 B1 · Direct digital synthesis based phase shift digital beam forming

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- Number: US 10,374,675 B1
- Document ID: US10374675B1
- Status: Granted
- Kind: B1
- Application number: 15/913,835
- Filed: 2018-03-06
- Granted: 2019-08-06
- Earliest claimed: 2018-03-06
- Assignees: Raytheon Company
- Applicants: Raytheon Company
- Inventors: Harry B. Marr; Daniel Thompson; Ralston S. Robertson
- Web page: https://patentgrep.com/patent/US10374675B1

## CPC

- H04B 7/0617: {for beam forming}
- G01S 7/032: {Constructional details for solid-state radar subsystems}
- H01Q 3/36: with variable phase-shifters
- G01S 13/282: {using a frequency modulated carrier wave (G01S13/286 takes precedence)}
- G01S 13/286: {frequency shift keyed}
- G01S 13/288: {phase modulated}
- G01S 2013/0245: {Radar with phased array antenna}
- H04B: TRANSMISSION
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A system for beamforming, in a phased array antenna. Subtraction of a sinusoidal signal from a received signal, or from a signal to be transmitted, is used to shift the phase of the received signal, or from a signal to be transmitted. A separate sinusoidal signal may be generated for each antenna array element, making it possible to shift the phase on a per-element basis, to perform beamforming.

## Claims

### Claim 1

A transmitter, comprising:
a first antenna element;
a second antenna element;
a first waveform generator;
a second waveform generator;
a third waveform generator;
a first differencing circuit,
having:
a first input connected to the first waveform generator,
a second input connected to the second waveform generator, and
an output operatively coupled to the first antenna element, and
being configured to generate at the output a difference between a signal at the first input and a signal at the second input; and
a second differencing circuit,
having:
a first input connected to the first waveform generator,
a second input connected to the third waveform generator, and
an output operatively coupled to the second antenna element, and
being configured to generate at the output a difference between a signal at the first input and a signal at the second input,
wherein the first waveform generator is configured to generate a modulated waveform.

### Claim 2 (depends on 1)

The transmitter of claim 1, wherein the second waveform generator is configured to generate a piecewise sinusoidal signal and the third waveform generator is configured to generate a piecewise sinusoidal signal.

### Claim 3 (depends on 2)

The transmitter of claim 2, wherein each of:
the first waveform generator;
the second waveform generator;
the third waveform generator;
the first differencing circuit; and
the second differencing circuit,
is a portion of a digital circuit.

### Claim 4 (depends on 3)

The transmitter of claim 3, further comprising:
a first digital to analog converter having:
an input connected to the output of the first differencing circuit, and
an output;
a first mixer having an intermediate frequency port, a local oscillator input, and a radio frequency port, the intermediate frequency port being connected to the output of the first digital to analog converter;
a first filter having:
an input connected to the radio frequency port of the first mixer, and
an output;
a first amplifier having an input connected to the output of the first filter and an output connected to the first antenna element;
a second digital to analog converter having:
an input connected to the output of the second differencing circuit, and
an output;
a second mixer having an intermediate frequency port, a local oscillator input, and a radio frequency port, the intermediate frequency port being connected to the output of the second digital to analog converter;
a second filter having:
an input connected to the radio frequency port of the second mixer, and
an output; and
a second amplifier having an input connected to the output of the second filter and an output connected to the second antenna element.

### Claim 5 (depends on 3)

The transmitter of claim 3, wherein the digital circuit is a hard-wired digital circuit.

### Claim 6 (depends on 3)

The transmitter of claim 3, wherein the digital circuit is a programmable digital circuit.

### Claim 7 (depends on 1)

The transmitter of claim 1, wherein the first waveform generator comprises a direct digital synthesizer.

### Claim 8 (depends on 1)

The transmitter of claim 1, wherein each of:
the second waveform generator; and
the third waveform generator
comprises a direct digital synthesizer.

### Claim 9

A receiver, comprising:
a first antenna element;
a second antenna element;
a first waveform generator;
a second waveform generator;
a first differencing circuit,
having:
a first input operatively coupled to the first antenna element,
a second input connected to the first waveform generator, and
an output, and
being configured to generate at the output a difference between a signal at the first input and a signal at the second input;
a second differencing circuit,
having:
a first input operatively coupled to the second antenna element,
a second input connected to the second waveform generator, and
an output, and
being configured to generate at the output a difference between a signal at the first input and a signal at the second input; and
an adding circuit, having a first input connected to the output of the first differencing circuit and a second input connected to the output of the second differencing circuit,
wherein each of:
the first waveform generator; and
the second waveform generator
comprises a direct digital synthesizer.

### Claim 10 (depends on 9)

The receiver of claim 9, wherein the first waveform generator is configured to generate a piecewise sinusoidal signal and the second waveform generator is configured to generate a piecewise sinusoidal signal.

### Claim 11 (depends on 10)

The receiver of claim 10, wherein each of:
the first waveform generator;
the second waveform generator;
the first differencing circuit;
the second differencing circuit; and
the adding circuit,
is a portion of a digital circuit.

### Claim 12 (depends on 11)

The receiver of claim 11, further comprising:
a first analog to digital converter having:
an output connected to the first input of the first differencing circuit, and
an input;
a first mixer having an intermediate frequency port, a local oscillator input, and a radio frequency port, the intermediate frequency port being connected to the input of the first analog to digital converter;
a first filter having:
an output connected to the radio frequency port of the first mixer, and
an input;
a first amplifier having an output connected to the input of the first filter and an input connected to the first antenna element;
a second analog to digital converter having:
an output connected to the first input of the second differencing circuit, and
an input;
a second mixer having an intermediate frequency port, a local oscillator input, and a radio frequency port, the intermediate frequency port being connected to the input of the second analog to digital converter;
a second filter having:
an output connected to the radio frequency port of the second mixer, and
an input; and
a second amplifier having an output connected to the input of the second filter and an input connected to the second antenna element.

### Claim 13 (depends on 12)

The receiver of claim 12, wherein each of:
the first filter, and
the second filter
is a band-pass filter.

### Claim 14 (depends on 11)

The receiver of claim 11, wherein the digital circuit is a hard-wired digital circuit.

### Claim 15 (depends on 11)

The receiver of claim 11, wherein the digital circuit is a programmable digital circuit.