An Efficient Plasmonic Photoconductive Antenna for Terahertz Continuous-Wave Applications

An efficient terahertz (THz) photoconductive antenna (PCA) are proposed in this paper. The antenna is designed for continuous wave (CW) applications in the frequency range of 0.5-3 THz. The overall optical-to-THz efficiency of the proposed PCA is improved by enhancing the optical-to-electrical and radiation efficiencies. For the presented PCA, three types of excitation gap are investigated numerically and are compared. To enhance the excited photocurrent, plasmonic excitation is applied to amplify the electric field distribution in the structure. Owing to plasmonic excitation, the optical-to-electrical efficiency of photomixer is increased by a factor of 100. Moreover, the substrates of the proposed PCA is reshaped to improve the radiation efficiency, directivity and side lobe level (SLL). Finally, the radiation characteristics of the proposed PCA is compared with conventional extended-hemispherical lens antenna. The comparison shows a 4-fold reduction in size achieved by the proposed antenna compared to those with similar radiation features.