Antenna Array Antenna Array Driven by Broadband Integrated Multibeam Network With Flat Amplitudes and Phases

This paper presents a broadband integrated Butler Matrix beamforming network (BFN). This proposed Butler Matrix BFN operates between the bandwidth of 28 GHz to 32 GHz and is implemented with subtrate integrated waveguides (SIWs). To facilitate the design and enhance the output amplitude and phase response, the phase shifters are incorporated into the design of directional couplers. Thus, the design of phase shifters doe not take the phase of crossover as a reference. The compensating SIW phase shifter is introduced into the design of −45° phase shifter, which helps to enhance the phase response over the operating bandwidth. The simulated phase dispersions of the designed Butler Matrix BFN are with peak to peak errors of only 13°, and the amplitude response over the bandwidth is −6 3 ± 1.2 dB. The designed Butler Matrix BFN would be a potential candidate in future 5G communications and other wireless communication systems.