Multi-mode dual-feed array radar antenna

摘要

A multi-aperture array antenna provides a narrow beam width, low side lobe radiation pattern for an illuminating beam through the forward feed of a ladder-type feed structure. Alternatively, the rear feed of the ladder network is so electrically tapered as to provide three simultaneous low side lobe smaller apertures which can be independently directed via phase shifters to provide distinct received beams for interferometric phase comparison. A feed connected to one radiating element in each of the three apertures form a broad-beam pattern for side-lobe cancellation. A phase shifter is positioned adjacent to each radiation element to steer the beam and switch between antenna functions by precise control of the phase excitation to each port. The feed structure is connected in a ladder configuration forming a front feed and a rear feed. The front feed network is connected through one feed structure to the transmitter such that all the radiating elements can be used to generate a single high gain, narrow illuminating beam aperture for searching and mapping. The rear network is connected through three distinct feed structures to a separate receiver, such that each receiver uses one-third of the radiating elements forming separate lower gain, wider beam apertures for azimuth direction finding by interferometric measurements. The three separate apertures formed through the rear feed network can also be independently directed through proper control signals applied to the phase shifters.