A Novel Liquid Crystal Phase Shifter Enhanced Butler Matrix Topology for Continuously Steerable 60 GHz Antenna Array

In this paper, a continuously steerable 1x4 antenna array operating at GHz is presented. Traditional Butler matrix networks provide discrete beam steering, limiting their flexibility for modern high data rate millimeter-wave applications. To overcome this limitation, a novel hybrid topology is proposed in which tunable liquid crystal (LC) phase shifters are integrated into the Butler matrix. This configuration enables smooth and continuous beam steering across the angular range without relying on complex control schemes or mechanical movement. A key advantage of the proposed design over conventional LC-based phased arrays is the significantly reduced phase shift requirement. Thanks to the directional biasing introduced by the Butler matrix, only of differential phase shift is needed from the LC elements to achieve full angular coverage by interpolating between Butler-defined beam directions. The LC phase shifters are optimized for GHz operation and integrated seamlessly into the network without degrading broadband characteristics. Simulation results validate continuous beam steering over maintaining low sidelobe levels and flat gain, making the design well-suited for dynamic GHz communication systems.