Switched-Beam Smart Antenna for Wi-Fi 8 Solutions in FTTR Applications

Fiber-to-the-room (FTTR) is a new in-premises indoor network technology relying on the optical fiber backhauling to deliver Wi-Fi connectivity in each room with a Quality of Service (QoS) superior than traditional Wi-Fi systems. This paper presents a high-gain switched-beam antenna with a cost-effective design for multi-Access Points (Multi-APs) solution, mainly for FTTR, to improve Wi-Fi 8 indoor coverage and reliability. The antenna spatial switchable pattern diversity is optimized for Wi-Fi sub-6 GHz range of 5.15 to 5.87 GHz and with cost-effective standard FR4 substrate. It reduces EM Interferences (EMI) between APs by reducing radiation in unnecessary directions, at least 20 dB, which also improves FTTR power consumption, compared to conventional multi-AP antennas. We optimized the antenna's radiation performance in CST Microwave Studio, then prototyped and measured it in an anechoic chamber. Experimental qualifications of the fabricated antenna and the feeding systems accordingly demonstrate good agreement with simulated antenna characteristics. Each of four generated beams illuminates one-quarter of the room, with realized Gain of approximately 5 dBi, Envelope Correlation Coefficient of 25 dB, ensuring that each MIMO stream can operate independently. The overlapped high-gain beams into the entire room space minimizes the combined Gain and allow transmit power to have sufficiently high level while complying with the regulated limits of Effective Isotropic Radiated Power (EIRP). Further studies are ongoing to present advantages of beam-switch antennas and the spatial division of the radiation pattern in the rooms to improve Wi-Fi coverage and throughput for a FTTR Wi-Fi user. This approach aims to reduce the dependency of such performance on each AP installation and location in the room, compared to the first generation of FTTR without switch-beam features.