Multiband THz Antenna for Non-Invasive Oral Cancer Diagnosis

The Tera Hertz (THz) wave is advantageous for clinical cancer diagnosis due to its nonionizing nature and high sensitivity to tissue structure, hydrogen bonds, and water content. These waves are capable of differentiating healthy and cancerous tissues because of their sensitivity to water content and molecular structures. This paper presents the design and analysis of two novel multiband THz antennas, which demonstrate exceptional performance in terms of return loss, peak gain, and gain bandwidth. The proposed antennas are designed by considering the substrate as Rogers 5880. The height of the substrate and its permittivity are <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0.25}\ \mu m$</tex> and 2.2, respectively. Both antennas operate effectively across multiple frequency bands, with antenna 1 achieving resonant frequencies at 0.216 THz, 0.424 THz, 0.503 THz, and 0.668 THz and peak gain values of 7.83 dB, 7.86 dB, 6.71 dB, and 9.09 dB, respectively. Similarly, antenna 2 resonates at 0.217 THz, 0.514 THz, 0.528 THz, and 0.582 THz, with corresponding peak gains of 8.08 dB, 7.54 dB, 7.42 dB, and 7.23 dB. These antennas exhibit excellent impedance matching, with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{11}$</tex> values as low as -35.82 dB and -30.3 dB, ensuring minimal signal reflection. Furthermore, the resonant frequency range of the proposed antennas aligns well with the THz frequency spectrum, which is highly suitable for biomedical applications such as oral cancer diagnosis.