Monopulse Networks for Series Feeding an Array Antenna

Series networks for feeding an array antenna are attractive because they can be designed compactly. A series "ladder" network is available which is particularly applicable for feeding a monopulse array antenna since it has complete independent control of the sum and difference excitations, minimum dissipative loss, and physical symmetry. This network consists of primary and secondary transmission lines feeding two sets of directional couplers that are interconnected to resemble a ladder. To obtain physical symmetry, the ladder is fed at the center by two hybrid junctions and an additional directional coupler. An experimental array fed by a ladder network was fabricated and tested. The design objectives of 25 dB sidelobe suppression for the sum and difference mode patterns were achieved.