Antenna Arrays for Physical Layer-Based Directional Networking Technology

Abstract

Due to the terrain (mountains, ridges, forest, and vast areas) challenges in the rural areas, it is difficult and costly to implement broadband and affordable coverage with currently available wireless technologies. To overcome communication networking challenges in rural areas, an advanced directional networking technology has been proposed. The approach is based on enhancing intelligence and logic capabilities in the physical layer without causing changes in the other OSI layers of the communication network. Low-cost and low-profile circularly polarized antenna arrays and beam-switching feed networks are fundamental building blocks in this approach. A broadband long-slot antenna array fed by simplified microstrip structures was designed to cover the frequency band of 4–6 GHz. For lower profile, a narrower band (4.4–5.1 GHz) high-gain stacked-patch-antenna array with annular gap was also developed. For low cost and fast beam switching, a compact broadband microstrip-based 8 × 8 Butler matrix was realized with a compact crossover. The antenna arrays and the Butler matrix were fabricated and experimentally characterized. Simulation results were verified with the measured results, as well as the beam-switching capability of the antenna arrays and the Butler matrix.