Electronic rotman lens

Patent metadata

Field	Value
Publication number	US-2016248172-A1
Application number	US-201414199126-A
Country	US
Kind code	A1
Filing date	Mar 6, 2014
Priority date	Mar 6, 2014
Publication date	Aug 25, 2016
Grant date	—

Abstract

Embodiments are directed to operating an analog signal processing circuit to emulate a Rotman lens. The analog signal processing circuit applies a plurality of time delays to a plurality of signals associated with a plurality of beam ports. The analog signal processing circuit forms a plurality of output beams for transmission by a plurality of array ports included in an array based on the time delayed signals by summing the time delayed signals. The time delays are based on a direction of transmission of the output beams.

First claim

What is claimed is:

1 . A method for operating an analog signal processing circuit to emulate a Rotman lens, the method comprising:
applying, by the analog signal processing circuit, a plurality of time delays to a plurality of signals associated with a plurality of beam ports; and forming, by the analog signal processing circuit, a plurality of output beams for transmission by a plurality of array ports included in an array based on the time delayed signals by summing the time delayed signals, wherein the time delays are based on a direction of transmission of the output beams.

2 . The method of claim 1 , wherein the analog processing circuit comprises switched sample-and-hold circuits, the method further comprising:
coupling, by a first series of the sample-and-hold circuits, a first beam port included in the plurality of beam ports to a first array port included in the array.

3 . The method of claim 2 , further comprising:
coupling, by a second series of the sample-and-hold circuits, a second beam port included in the plurality of beam ports to the first array port; and summing an output of the first series of the sample-and-hold circuits with an output of the second series of the sample-and-hold circuits; and driving the first of the array port based on an output of the summation.

4 . The method of claim 2 , further comprising:
applying independent weights to each of the sample-and-hold circuits included in the first series.

5 . The method of claim 4 , further comprising:
using a floating-gate transistor circuit or a digital to analog converter (DAC) programmed to have a constant output wired to a gate of a transistor to implement the weights.

6 . The method of claim 1 , further comprising:
applying, by the analog processing circuit, a fast Fourier transform (FFT) algorithm and an inverse FFT algorithm in forming the output beams.

7 . The method of claim 6 , further comprising:
applying, by the analog processing circuit, a phase shift and summation matrix to an output of the FFT algorithm.

8 . The method of claim 1 , further comprising:
receiving a signal via the array ports; applying a fast Fourier transform (FFT) algorithm to the signal from each of the array ports to divide the signal from each of the array ports into frequency bins; summing each array port's frequency binned signals and applying a phase shift to each frequency bin for each input beam; and performing an inverse FFT algorithm on each input beam.

9 . The method of claim 8 , further comprising:
applying a FFT algorithm to a second signal to generate a plurality of beams; applying a phase shift to the generated beams; applying an inverse FFT algorithm to the phase shifted beams; and transmitting one or more outputs of the inverse FFT algorithm via the array ports;

10 . A system for emulating a Rotman lens, comprising:
a plurality of beam ports; an array comprising a plurality of array ports; and an analog signal processing circuit configured to form an output beam for transmission by the array ports based on applying a plurality of time delays to a signal from at least one of the beam ports, where the time delays are selected in accordance with a selected direction for transmission wherein the array is configured to simultaneously transmit multiple output beams by summing time delayed signals from multiple beam ports at each array port.

11 . The system of claim 10 , wherein the analog signal processing circuit is configured to form input beams based on the plurality of time delays applied to the array ports and summed at a beam port, and wherein the array is configured such that a plurality of time delays are applied to each array element to form multiple input beams simultaneously where the true time delays are selected in accordance with a selected direction for reception.

12 . The system of claim 10 , wherein the analog processing circuit comprises switched sample-and-hold circuits.

13 . The system of claim 12 , wherein a first series of sample-and-hold circuits couples a first of the beam ports to a first of the array ports.

14 . The system of claim 13 , wherein a second series of sample-and-hold circuits couples a second of the beam ports to the first of the array ports, and wherein an output of the first series of sample-and-hold circuits is summed with an output of the second series of sample-and-hold circuits, and wherein an output of the summation drives the first of the array ports.

15 . The system of claim 13 , wherein independent weights are applied to each of the sample-and-hold circuits included in the first series.

16 . The system of claim 15 , wherein the weights are implemented using a floating-gate transistor circuit.

17 . The system of claim 15 , wherein the weights are implemented using at least one of a current domain circuit and a charge domain circuit.

18 . The system of claim 10 , wherein the analog processing circuit is configured to apply a fast Fourier transform (FFT) algorithm and an inverse FFT algorithm in forming the output beam, and wherein the analog processing circuit is configured to apply a phase shift and summation matrix to an output of the FFT algorithm.

19 . The system of claim 10 , wherein the array ports are configured to receive a signal, and wherein the analog processing circuit is configured to:
apply a fast Fourier transform (FFT) algorithm to the signal from each of the array ports to divide the signal from each of the array ports into frequency bins; and sum each array port's frequency binned signals, apply a phase shift to each frequency bin, and perform an inverse FFT algorithm for each beam port.

Assignees

• Raytheon Co

Inventors

• Marr Harry B
• Schulte Jr Walter B
• Gianvittorio John P

Classifications

• H01Q15/02

  Refracting or diffracting devices, e.g. lens, prism · CPC title

• H01Q3/2676

  Optically controlled phased array · CPC title

• H01Q25/008 Primary

  lens fed multibeam arrays · CPC title

• H04B7/0671

  using different delays between antennas · CPC title

• G01S7/38

  Jamming means, e.g. producing false echoes · CPC title