Algorithms for remote calibration of active phased array antennas for communication satellites

This article describes two algorithms that are effective for the remote calibration of an N/sub e/ element active phased array antenna. These algorithms involve transmission of orthogonal encoded signals. The unitary transform encoding (UTE) algorithm is most suited for digital beamforming as it requires additional encoding hardware for an analog implementation. The control circuit encoding (CCE) algorithm is ideally suited for analog beamformers as it requires no additional encoding hardware. The CCE method encodes phased array elemental signals using a Hadamard matrix to control the switching of intrinsic phase shifter delay circuits. The UTE and CCE algorithms can reduce the average measurement integration times for the complete set of calibration parameters by /spl sim/N/sub e/ relative to the corresponding values for single-element calibration procedures.