A THz Lens Antenna fed by a Photoconductive Connected Dipole Array

Abstract

Photoconductive antennas have been used extensively for THz radiation the last few years. In this thesis, we propose a photoconductive connected dipole array consisting of 36x36 elements that is used as a feed in a THz silicon lens and radiates in a band ranging from 100 GHz to 5 THz. Specifically, we compute theoretically the radiated field patterns of the array as well as the secondary field beyond the lens. Furthermore, we investigate the feasibility of the fabrication of such a photoconductive connected array, given the challenges in 3D printing of a um-sized microlens array that is used to focus the laser power to the excitation gaps of the dipoles. We conclude that microlenses of sufficient accuracy can be fabricated in the premises of TU Delft without compromising the efficiency expected in theory. Lastly, we build a Matlab GUI that computes the far field radiated by various types and sizes of lens antennas in transmission, provided that the field radiated by the feed is already known. This tool has been successfully validated and supported the work in the first part of the thesis at the calculation of the far field of our proposed THz silicon lens antenna.