Enhanced and directional transmission through a slit surrounded with grooves in a conducting plane

Enhanced and directional transmission through a slit surrounded with grooves in a conducting plane is investigated. A boundary-value problem of electromagnetic wave scattering from a slit surrounded with a finite number of rectangular grooves on both surfaces in a conducting plane is rigorously solved based on the eigenfunction expansion, Fourier transform and mode matching method. The radiated power density and the transmission coefficient are represented in a series. Computation is performed to illustrate the transmission behaviours in terms of the groove geometry.