Time Domain Analysis of Terahertz Photoconductive Antennas Using High- Frequency Structure Simulator (HFSS)

In this thesis, an in-depth guide and description on how to model and perform frequency and mainly time domain analysis of a THz photoconductive antenna using HFSS will be presented. The main purpose of this thesis is to master and document the procedures for transient domain analysis in HFSS to fill the lack of documentation about this topic. Moreover, another goal is to compare the results from HFSS with the ones from another program, COMSOL (conducted by a PhD student), in order to validate the correctness of the procedure. From this thesis, it can be concluded that in order to obtain accurate results in the time domain there are some factors that need to be considered. One of this consideration is the fact that the mesh size in the time domain is much smaller than in the frequency domain and must be increased by using some mesh fixing techniques. Another consideration is the fact that while materials properties in the frequency domain can remain constant over a frequency range, in the time domain they automatically follow the Debye model but can be configured differently. Taken into account these considerations, the average electric field in the y-direction inside the substrate of an antenna with custom current source excitation was obtained and compared with the results from COMSOL. Since both results were identical, the procedures developed using HFSS to perform time domain analysis were validated, making this project a success.