1-D and 2-D Beam Steering Arrays Antennas Fed by a Compact Beamforming Network for Millimeter-Wave Communication

In this article, a new Beamforming Network (BFN) realized in Broadside Coupled Stripline (BCS) is proposed to feed 1 × 4 and 2 × 2 arrays antenna at 28 GHZ-Band. The new BFN is composed only of couplers and phase shifters. It doesn’t require any crossover compared to the conventional Butler Matrix (BM) which requires two crossovers. The tight coupling and low loss characteristics of the BCS allow a design of a compact and wideband BFN. The new BFN produces the phase differences of (±90◦) and (±45◦
, ±135◦ ) respectively in x- and y-directions. Its integration with a 1 × 4 linear array antenna reduces the array area by 70% with an improvement of the gain performance compared with the conventional array. The integration with a 2 × 2 array allows the realization of a full 2-D beam scanning. The proposed concept has been verified experimentally by measuring the fabricated prototypes of the BFN, the 1-D and 2-D patch arrays antennas. The measured 11.5 dBi and 11.3 dBi maximum gains are realized in θ0 = 14◦ and (θ0, φ0) = (45◦
, 345◦ ) directions respectively for the 1-D and 2-D patch arrays. The physical area of the fabricated BFN is only (0.37λ0 × 0.3λ0 × 0.08λ0), while the 1-D array and 2-D array antennas areas without feeding transmission lines are respectively
(0.5λ0 × 2.15λ0 × 0.08λ0) and (0.9λ0 × 0.8λ0 × 0.08λ0).