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Active array self calibration

  • US 5,682,165 A
  • Filed: 05/02/1996
  • Issued: 10/28/1997
  • Est. Priority Date: 05/02/1996
  • Status: Expired due to Term
First Claim
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1. A method for receive self calibration of an active RF antenna array system comprising a plurality of radiating elements arranged in an array aperture, a corresponding plurality of transmit/receive modules each including independently adjustable phase shifting circuitry, a transmit signal source for providing transmit signals and a receiver responsive to the signals received through the radiating elements and T/R modules to provide a receiver signal, the method comprising the following steps:

  • (a) placing a radar absorbing hat over the array aperture;

    (b) setting the transmit drive to an appropriate level to obtain linear operation of the receive module;

    (c) setting a given T/R module under test to a receive state;

    (d) setting a reference T/R module to a transmit state;

    (e) setting all other T/R modules in the array except the module under test and the reference module to a safe state so as not to transmit or receive through said other modules;

    (f) receiving pulses of RF energy at the module under test via its corresponding radiating element which has been transmitted through the reference module via its corresponding radiating element;

    (g) changing the state of the phase shifting circuitry of the receive module under test on a pulse-to-pulse or between groups of pulses to add phase modulation to the received pulses of energy to collect measurement data;

    (h) analyzing the measurement data to determine the relative phase difference between the transmit module and the receive module under test;

    (i) repeating the calibration for other modules in the array to obtain a set of data indicating the relative phase differences between the modules in the array, wherein only one module is transmitting and only one module is receiving during a test of a module under test; and

    (j) storing the set of data for use in setting the phase shifters for accurate receive beam forming.

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