A Novel Antenna for 8 Element Beam Forming Antenna Array using Butler Matrix

Abstract

This paper presents design of novel microstrip antenna for an 8-element linear array with 8x8 Butler Matrix as a beamforming network. The proposed structure resonates at 2.4 GHz frequency and is implemented using Microstrip Technology with FR-4 Substrate having ε r =4.3 and height=1.6 mm. Simulation results are given for the components (microstrip antenna, quadrature couplers, crossovers, phase shifters) used to implement the matrix. The 8-element antenna array is connected to the matrix to form a beamforming system and produces eight orthogonal beams at −55 • , −36 • , -21 • , -7 • , 55 • , 36 • , 21 • , and 7 • . The reflection coefficients and isolations at all ports are below −10 dB at the center frequency and side lobes of radiation pattern are sufficiently low. The applications for this technique are in lower frequency bands of 5G and LTE, wearable devices and IEEE 802.11 WLAN.