Design of a Wideband and High directive Log Spiral THz Antenna for Photoconductive Sources

This paper presents the design of a log spiral antenna operating at THz frequencies. The antenna was designed and simulated numerically by using the CST software within the frequency range 0.1–3.0 THz. It is found that the antenna is characterized with a wideband impedance matching which extends from 1.0 to 2.8 THz (|S11|< −10 dB)), high directivity with a maximum value Dmax = 5.61 dBi at 2.05 THz, high gain with a peak Gmax = 4.72 dBi at 2.2 THz, and high efficiency with a maximum ηmax = 81.5 % at 1.38 THz. With these obtained performances, we estimate that our proposed structure can be a good candidate for THz source applications.