Design of highly directive terahertz photoconductive dipole antenna using frequency-selective surface for sensing and imaging applications

The prospects for improving the gain and directivity of a photoconductive dipole antenna (PCA) using a bandpass frequency-selective surface (FSS) as a superstrate at terahertz frequencies for imaging and sensing applications are presented. The physical parameters of the proposed bandpass FSS for the PCA are determined using a simple synthesis technique based on a single square loop bandpass FSS. Furthermore, the effect of the unit-cell periodicity of the FSS on the resonance condition of the antenna structure is studied, and its effect on the gain, directivity, and front-to-back lobe ratio of the proposed antenna is also presented. Moreover, control over the transmission characteristics of the FSS in a particular frequency band is also discussed.