Microwave Devices Simulation with Ansoft HFSS

Some microwave passive devices for applications in microwave moisture content measurement, including waveguide absorption type variable attenuator, optimum H surface horn antenna, optimum pyramidal horn antenna, were simulated by Ansoft´s HFSS. Certain targets have been achieved, and it is a new attempt to apply the microwave simulation technology to instructing practice. The dielectric slab painted absorbing material (graphite powder) method or both sides of it inflicted resistance boundary condition method was separately used for the attenuator models. The latter method may achieve the big attenuation and satisfy the need of microwave moisture content measurement according to the simulation results. Optimum gain H surface horn antenna and pyramidal horn antenna with E and H 3dB lobe width equal were designed. The pyramidal horn antenna is better, which can obtain good antenna pattern, big gain and small VSWR according to the simulation results; therefore, it has been used widely in the microwave moisture content measurement.