×

Steerable transmit, steerable receive frequency modulated continuous wave radar transceiver

  • US 9,285,461 B2
  • Filed: 03/12/2013
  • Issued: 03/15/2016
  • Est. Priority Date: 03/12/2013
  • Status: Active Grant
First Claim
Patent Images

1. An apparatus, comprising:

  • a transceiver coupled to a dual-orthogonally polarized antenna assembly, capable of transmitting circularly polarized signals that are a component of a multi-element radar beam;

    a transmit phase shifting circuit in the transceiver, configured to apply a phase shift to a transmit signal from a local oscillator, in response to receiving transmit phase control signals;

    a power amplifier in the transceiver coupled to the transmit phase shifting circuit, having a differential output with a first port coupled through a first isolation coupler to a first polarity terminal of the dual-orthogonally polarized antenna assembly, for transmission of in-phase signals and with a second port of the differential output coupled through a second isolation coupler and a 90-degree phase delay to a second polarity terminal of the dual-orthogonally polarized antenna assembly, for transmission of quadrature-phase signals, the in-phase and quadrature-phase signals at the antenna assembly terminals forming a circularly polarized electromagnetic wave that is additively combined with circularly polarized electromagnetic waves transmitted from other transceivers, to perform phased-array beam steering of the multi-element radar beam in response to the transmit phase control signals;

    a power combining circuit in the transceiver, with a first input terminal coupled through the first isolation coupler to the first polarity terminal of the dual-orthogonally polarized antenna assembly and with a second input terminal coupled through the second isolation coupler to the second polarity terminal of the dual-orthogonally polarized antenna assembly, and an output terminal;

    a low noise amplifier in the transceiver, with an input terminal coupled to the output terminal of the power combining circuit, and an output terminal, configured to amplify a received circularly-polarized signal;

    a first mixer having a first input coupled to the first isolation coupler and a second input coupled to the output of the low noise amplifier, configured to output a difference signal at an output thereof, related to a difference in frequency of transmitted and received radar signals, with the difference signal generated using a signal in-phase with the local oscillator signal;

    a second mixer having a first input coupled to the second isolation coupler through a quadrature phase-shifting circuit and a second input coupled to the output of the low noise amplifier, configured to output a difference signal at an output thereof, related to a difference in frequency of transmitted and received radar signals, with the difference signal generated using a signal in quadrature with the local oscillator signal;

    a first variable-gain amplifier coupled to the first mixer, configured to amplify in-phase receive signals in response to a first weighted value of the receive phase control signals;

    a second variable-gain amplifier coupled to the second mixer, configured to amplify quadrature phase of the receive signals in response a second weighted value of the receive phase control signals; and

    a signal combining circuit coupled to outputs of the first and second variable gain amplifiers, configured to combine the amplified in-phase receive signals with the amplified quadrature phase of the receive signals, to rotate the phase of the received signal in response to the receive phase control signals, to steer a received multi-signal radar beam composed of signals reflected by an object, which were earlier transmitted from the other transceivers.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×