Design of THz Antennas for a Continuous-Wave Interdigitated Electrode Photomixer
Jepsen, Peter Uhd; Krozer, Viktor (Department of Photonics Engineering–Department of Electrical Engineering, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby, Denmark)
The design of a dual-slot antenna integrated with an interdigitated electrode (IDE) LT GaAs photomixer together with choke filters and a dielectric lens, optimized for high output power at an operating frequency of 1 THz is proposed. An equivalent-circuit model for determination of coplanar waveguide (CPW) IDE capacitance is suggested, in order to tune it out using a dual-slot antenna. The initial design based on a Smith chart approach has been validated by carrying out exhaustive simulations in CST MicroWave Studio software. The radiation efficiency, incase of a dual-slot antenna integrated with a lumped capacitor element is found to be 81% with a directivity value of 11.47 dBi. The effect of choke filters on different antenna radiation parameters is also investigated. A 3-fan CPW radial stub gives a radiation efficiency of 62% with a directivity of 10.5 dBi and has a potential of providing better performance.
