Novel terahertz photoconductive antenna structures for sensor and communication applications

Abstract

The terahertz region of the electromagnetic spectrum is one of the widely explored areas over the past two decades due to the extraordinary properties of terahertz waves and their potential applications. This region remained unexplored due to the unavailability of efficient sources and detectors. However, in the recent days, extensive research has been carried out to explore this portion of the spectrum using schemes borrowed from its neighbouring regions to exclusively create devices to generate terahertz. newlineOne of the important technologies used to develop sources and detectors for terahertz waves is the photoconduction principle. It works on the concept of employing antennas from the microwave/RF domain and lasers from the optical domain, to obtain the emission from the radiator. The main objective of this thesis is to design and analyse terahertz photoconductive antennas using optoelectronic schemes followed by EM techniques. newlineInitially, a basic terahertz microstrip patch antenna is designed on a silicon substrate to obtain multiband resonances at the lower terahertz region, employing graphene as the radiator. The frequency dependent conductivity of graphene is calculated using Kubo s formalism and its chemical potential is varied to tune the frequencies. Utilizing graphene provides the advantage of employing a single structure to tune the frequency of operation and also provide multiple resonances, as fabrication of multiple devices to operate at separate frequencies is a major drawback at such small dimensions. newline