Comparison of terahertz antennas

There are many problems associated with THz technique. For example, how to design efficient THz antennas that are very different from the conventional antennas. There has been very little publication on this subject. This paper is aimed at addressing this problem. Due to how THz signals are generated, there are basically two types of THz antennas: the conventional antennas and photoconductive antennas . In THz region, the skin depth of a conductor is very small, thus conductive loss could be very high. Photoconductive antenna is the one attracted more attention and it seems to performance better. Normally a photoconductive antenna has a coplanar stripline structure. It consists of a semiconductor substrate and a coplanar stripline with a dipole antenna fabricated on the substrate. Some recent researchers observed that if being added the indentations at the edge of the dipole, the antenna can get a better performance on generating the signals. In this paper, we will not only compare various THz antennas, but also explain the reasons, such as why the indentations can improve the performance of the antenna. Some simulation results will also be provided to aid our discussion.