Design of circularly polarized terahertz antenna with interdigital electrode photomixer

In the paper, we present the design of a circularly polarized antenna operating at 1 THz. The antenna is intended to be used for security applications where the object does not require a specific orientation for an optimal detection. In order to radiate high power, we integrated an LT GaAs photomixer with an interdigital electrode, choke filters and a dielectric lens into the antenna structure. Since a good impedance matching between the antenna and the photomixer is essential for radiating a high output power, we developed an equivalent model of the interdigital electrode and computed its capacitance to precisely design the matching circuit. The functionality of the designed structure was verified by simulations in CST Microwave Studio.