Waveguide-Based Phased Array With Integrated Element-Specific Electronics for 28 GHz

Scalable and beam-steerable phased antenna array prototype for the wireless backhaul communication is presented for the 28 GHz. The 16-element phased array consists of low-loss waveguide power division network, waveguide-to-PCB transitions, phase shifters on PCB, and horn antenna elements fed from the PCB. The paper presents a state-of-the-art design where the electronically controlled phase shifters are implemented on the PCB right in the immediate proximity of the radiating elements. Thus, the transmission losses are kept as low as possible, even though each element has their specific PCB-mounted electronics. The design is scalable so that element-specific parts on the PCB do not consume more area than the antenna element. Furthermore, novel matching steps with easy manufacturing are presented in the power division network. The simulated and measured results show good agreement. The measurement results show that the grating-lobe free beam-steering range is ±20° in both azimuth and elevation. The measured antenna gain at broadside is 11.3 dBi after element phase adjustment, and the majority of the losses are due to the implemented electronics, i.e., the phase shifters.