Double-channel narrowband terahertz filter based on parallel plate waveguide cavities

A tunable double-channel narrowband terahertz filter integrated with parallel plate waveguide cavities is described. The filter is formed by machining two rectangular grooves into upper and bottom plates of parallel plate waveguide, respectively. Tuning is achieved by a relative lateral shift of two metal plates with rectangle grooves. Simulation results show that both the resonance frequency and the Q values can be tuned by simply changing the separation between two grooves.