Multi-band hybrid for WiFi

Abstract

Hybrid is an important wireless communication element, which could be used to construct balanced mixer, balanced amplifier, constant phase shifter and beam-forming network. With the increasing demand on wireless communication, the more and more wireless communication standards are required. Wi-Fi is one of the wireless communication systems with multiple standards. Engineers are attracted to develop a multiband and compactable size microwave circuit that could operate at two or more arbitrary frequency band. This report is aimed at the hybrid which could fulfil the Wi-Fi ISM band 2.4GHz, 5.2GHz and 5.8GHz. A 4x4 Butler Matrix, several hybrids and a phase shifter have been designed, fabricated and measured respectively in this project. The constructed hybrids were based on different requirements and theories. The transmission line theory, impedance matching, slow-wave have been proved in the design process. The phase shifter, with parallel open and short stub, small size, has been constructed. The measured result of the phase shifter has made a good agreement with the simulation, the method of open and short stub has been verified. And the beam-forming network, a Butler Matrix has constructed with new structure, which is equipped with lower loss than the traditional structure.