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This paper describes the design, fabrication, and testing of a seven-element S-band phased array, in which the beam is steered by means of a coupled-oscillator technique. Seven monolithic-microwave integrated-circuit-based voltage-controlled oscillators were coupled via microstrip transmission lines in such a manner that they mutually injection locked and, thus, oscillated as an ensemble. The output of each oscillator was connected to a microstrip patch array element and the seven elements were disposed in a line on a Duroid substrate. The resulting antenna was characterized in benchtop tests, revealing the relative phase behavior of the oscillators, and in range tests, producing far-field pattern cuts. Patterns showing beams steered to several angles were obtained by applying appropriate tuning voltages to the end oscillators of the array.

In this paper, we describe the fabrication of the array of voltage controlled oscillators, the experimental determination of the behavior of this array, and comparison of the experimentally observed behavior with theoretical predictions. We further discuss the design of the microstrip patch radiating aperture and describe the experimental measurement of the antenna patterns under various scan conditions.