Patent attributes
A method for calibrating a phased-array antenna that involves transmitting a signal from a transmitting element, and sequentially receiving the transmitted signal at two receiving elements each spaced a first distance from the transmitting element. This step is then repeated one or more times, but transmitting from a different transmitting element in each repetition of the step, until each element being calibrated has received at least one transmission. Then, the first distance is changed to a second distance, and the steps are repeated one or more times to gather additional measurements. These measurements allow the determination from the received signals of two separate element mutual coupling ratios, one ratio for one subset of the elements being calibrated and the other for a second subset comprising the remaining elements being calibrated. Next, at least four additional transmissions and receptions are made via two transmissions each from two transmitting elements comprising one element of each subset, and the reception of transmissions from each of these two transmitting elements by each of two receiving elements, the two receiving elements being different elements than the two transmitting elements. From these last measurements a complex calibration ratio for all of the elements being calibrated with respect to a single element is determined. For calibration in the transmit mode, this same procedure is followed, but the transmissions become receptions and the receptions become transmissions.
