Terahertz Photoconductive Antenna Based on Tai-Chi Totem and Plasmonic Structure for Cancer Detection

The asymptomatic nature of cancer in its early stages has been a major problem in medical research. Terahertz (THz) radiation has great potential in cancer detection due to its outstanding properties of non-ionization, non-invasion, and accuracy. As an auspicious THz radiation source, the photoconductive antenna (PCA) is now becoming adopted in investigating and analyzing THz applications. In this paper, a fabricable novel structure of THz PCA working on THz band is proposed. The design of plasmonic contact fingers is applied to the antenna gap in order to improve the efficiency by enhancing the absorption of surface current, leading to a larger THz radiation. The proposed design is analysed and compared to the conventional design, indicating that the directivity and E-field magnitude of the proposed work are significantly improved in range of 0.3 to 0.6 THz, up to 7.33 dBi and 20.33 V/m. The E-field distribution inside the structure and at the electrodes-substrate interface is provided to show the superior optical absorption by the plasmonic contact fingers. The proposed PCA fulfils the requirements of cancer detection and other medical biosensing scenarios.