Compact 4 × 4 Butler matrix design-based switch beamforming antenna
array for 5G applications
Abstract
This paper, presents a 4×4 BM based on four direction switch BM antenna
array. The proposed design operated at 3.5 GHz. The use of multi-beam
antennas or switched-beam antenna arrays (SAAs) promised users of
high-gain and large coverage areas for 5G technologies. The BM was
implemented by combining 3-dB BLC, two crossovers, and 45
o phase shifters fabricated on the RT5880LZ substrate,
with using a triangular slot and T-shape based on the BM design. The
proposed design focused on the miniaturization and enhancement of the
bandwidth. The return loss and isolation were better than -15 dB at all
the ports, according to the simulated and measured result showed that
with excellent insertion loss -6.1 ± 2 dB. A fractional bandwidth of
49.7% and the overall dimension were reduced to 56% as compared to the
conventional BLC and crossover. Hence, the proposed design of BM
performed an excellent size reduction of 80% and improvement bandwidth
up to 836 MHz compared to the traditional BM. The switched beam
directions were measured at -34 o, -40
o, +32 o and +35 o
at 3.5 GHz for each input port of 1-4 excitation. The proposed design BM
is suitable of 5G application.