Tapered Radial Fed Circuit and Varactor-Mounted Waveguide Switch for Millimeter-Wave Switched Sector-Beam Antenna

This paper describes the simulated designs of an improved radial fed circuit and a varactor-mounted waveguide switch, which are expected to play important roles in the realization of a millimeter-wave switched sector-beam antenna. The aim of this antenna´s development is to realize an ultra-high-speed gigabit-rate wireless LAN. In this paper, an eight-sector beam antenna is described. The radial structure is designed so that the input power from a unique RF port at the structure´s center can be sent to any one of the selected sectors with maximum power under the required bandwidth. The simulation results of the proposed tapered radial structure show that the bandwidth of S₂₁, with an insertion loss of -1.0 dB in the frequency range of 59-66 GHz, is 5.4 GHz, which is the three times that achieved in our previous work. Basic study is also carried out on factors such as choke structure, switch position, and the losses caused by the dielectric and metallic materials as well as the parasitic components of the varactor of the proposed waveguide switch