Abstract: An array antenna system having a predetermined electric current distribution on an antenna aperture to form a desired shape of antenna beam. Active antenna elements arranged on the aperture transmit a signal for electronically scanning a predetermined region to detect a target and receive a signal reflected by the target. Passive antenna elements are also arranged on the aperture. The antenna system further includes a direction finding section including reception antenna elements which receive an incident signal. The active, passive and reception antenna elements are positioned to allow a predetermine electric current distribution to be established on the antenna aperture.

Abstract: A phased array antenna includes a plurality of first antenna elements and a plurality of phase shifters respectively connected to the first antenna elements. An amplitude and a phase of each of the antenna elements are determined by a method of opposing a pick-up antenna at a distance from the phased array antenna to measure a composite power of the phased array antenna while changing phases of the phase shifters for determining the ratio of the maximum power to the minimum power, and the phase value for the maximum power, from which the amplitude and phase are computed.

Abstract: A microstrip antenna offering a wide bandwidth while suppressing the standing wave ratio is obtained by interposing a conductor plate between a radiating conductor element and a ground plane conductor.