Patent ID: 8593337

Claim:
A phase calibration method for a phased array antenna, the phased array antenna comprising: an oscillator that generates radio waves; a plurality of antenna elements; a plurality of phase shifters, each of which is connected to each of the plurality of antenna elements and changes a phase of radio waves radiated by the plurality of antenna elements; means for distributing radio waves generated by the oscillator to the plurality of antenna elements via the plurality of phase shifters; means for controlling the plurality of phase shifters and the distributing means; and a signal input part that inputs received signals outputted from a receiver that detects power of radio waves radiated by the plurality of antenna elements; and the phase calibration method comprising: at the controlling means, calibrating a phase of each of the phase shifters for each pair of antenna elements located at a pair of positions symmetric with respect to a central axis of an array of the phased array antenna, among the plurality of antenna elements; and subsequently performing, with respect to an antenna element located at a position of the central axis of the array and all pairs of antenna elements located at positions symmetric with respect to the central axis of the array, the steps of: supplying radio waves from the oscillator via the distributing means to an antenna element located at a position of the central axis of the array and a pair of antenna elements located at positions symmetric with respect to the central axis of the array, among the plurality of antenna elements; obtaining a directivity pattern formed by the antenna element and the pair of antenna elements from a distribution in a received power of the radio waves, received at the receiver via the signal input part, along a horizontal direction with respect to an array direction of the plurality of antenna elements, while changing a phase of each of the phase shifters connected to the pair of antenna elements in the same manner; and setting a value of the phase of each of the phase shifters in such a manner that a level of side lobes, which occur in the directivity pattern obtained, becomes a predetermined value.