Shaped horn antenna for spot focusing THz imaging application

A novel shaped horn antenna is proposed to improve the spot focusing and imaging systems performance at terahertz frequencies. In this paper, a waveguide-horn-waveguide structure scheme is used to model a horn antenna in order to avoid lens corrected on horn apertures usually needed to enhance the focusing. The shaped horn and lens corrected horn are compared for performance comparison at 0.92, 0.94, 0.98 and 1THz keeping horn aperture diameter 1.7mm and length 3.1mm for both type of horn antennas. The horn antennas are designed and simulated with an accurate proprietary Body-of-revolution Finite-Element code and fed by circular waveguide operating at TE11 mode. Comparison study highlighted that, the shaped horn provided slightly better spot focusing of 0.16, 0.15, 0.08 and 0.09mm as compared to lens corrected horn. The proposed shaped horn is found suitable candidate for frequency domain near field focusing in terahertz imaging systems.