A Reconfigurable Beamsteering Antenna Array at 28 GHz Using a Corporate-Fed 3-Bit Phase Shifter

Abstract

A 3-bit beam steerable antenna array based on a microstrip line is designed and implemented at 28 GHz for millimetre-wave application. The antenna consists of an 8-element tightly stacked aperture and a switchable feeding network. The latter consists of a one-to-eight-way uniform microstrip corporatefed power divider and is separated from the radiating element by a ground plane. To achieve coupled feeding, the ground plane has two rows of slots under each antenna element. A switching mechanism was implemented on the microstrip line to realize 3-bit periodic phase shifting for beamsteering. By sampling 8 feed points with a separation distance of λ/8, a 3-bit phase shifter was constructed with phases of 0and −315 • . Continuous beamsteering was achieved from −50 • to +50 • by switching eight different sampling states, both in numerical calculation and in simulation. The design was verified by fabricating and testing three different prototype configurations at 28 GHz. The measured prototypes showed an excellent match with the simulation results. Notably, the maximum measured gain was found to be 13.44 dBi with a gain threshold of 10 dBi within the steering range (viz. 100 • ).INDEX TERMS Reconfigurable, millimeter-wave antenna, aperture-fed antenna, 3-bit-phase shifter, beamsteering.

Design of a Compact and Minimalistic Intermediate Phase Shifting Feed Network for Ka-Band Electrical Beam Steering

“…This discrepancy results from the mutual coupling between antennas. A Similar observation was made in [ 30 ]. The feed network does not have Wilkinson power dividers due to the lack of space.…”

“…Therefore, a high-density design is paramount. Other similar works [ 29 , 30 ] operating in the Ka -band were not able to achieve this. They fabricated and measured only passive versions of the original reconfigurable designs.…”

“…Moreover, their main performance metrics are compared in Table 6 . It should be noted that the most similar works in the Ka -band are [ 29 , 30 ]. However, they were not able to fabricate the full system since the reconfigurable components were replaced with short or open connections.…”

“…The above result is significant since other Ka -band reconfigurable feed networks [ 29 , 30 ] are missing complete biasing structures and components in their fabricated designs. The potential reasons are the lack of space or difficulties in obtaining the biasing.…”

“…Therefore, the designs were limited to low frequency bands below 10 GHz. As discussed before, the similar Ka -band designs [ 29 , 30 ] did not contain a full design. Our biasing method provides a way to implement fully fabricatable and functional designs in the Ka -band.…”