Abstract: A built-in coupling means (14) for coupling test signals to an electronically scanned antenna (13), thereby permitting the iterative establishment of corrected phase setting on individual phasers (19') associated with respective radiation elements (17) in said antenna (13).

Abstract: In a slotted array antenna (12), an asymmetric ridge waveguide element (13) defining colliner radiating slots (16), said waveguide elements (13) defining a central hollow region (13') and an axial ridge (13") separating first and second series of side chambers (17' and 17") alternating in height with respect to each other, whereby production of second order beams of radiation from said antenna (12) is eliminated and much lower side lobe levels are produced when the element (13) is used in an array scanned in a plane perpendicular to the element axes.

Abstract: 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.