Tunable 3 × 3 Nolen Matrix Network for Power-Saving Phased Array

Abstract

In this article, a tunable Nolen matrix with small phase tuning range phase shifters and simple control is presented. The proposed circuit topology is constructed from $3\times 3$ Nolen matrix embedded with three tunable phase shifters with small tuning range of 0°–120°. For each input port excitation in this proposed network, a continuous 120° tunable progressive phase difference is obtained at the output ports, and the full 360° tunable phase progression is achieved by exciting all three input ports. Most importantly, all tuning range relaxed phase shifters are controlled simultaneously by only two-channel dc voltages to achieve full progressive phase tuning range, which can simplify the control method of beam steering. Compared to the conventional feeding matrix, the proposed design achieves a flexible progressive phase, compact size, easy control, and low power consumption. The theoretical analysis is carried out for the proposed circuit topology, and the closed-form equations are derived to minimize the phase shifter’s tuning range and reduce the control complexity. To verify the proposed design concept, a prototype tunable Nolen matrix operating at 5.8 GHz is designed and tested, and the experimental results agree well with simulation and theoretical analysis.