Terahertz Antenna Design for Biomedical Sensing and Imaging

Abstract

Background/objectives: Research in terahertz (THz) frequency range has accelerated, bridging the gap between microwave and infrared technologies, in response to the increasing demand for quicker data transmission, improved image resolution, and effective biomedical diagnostics. The non-ionizing nature of the THz band makes it highly suitable for high-resolution imaging and noninvasive biomedical sensing. The choice of substrate, however, significantly impacts on THz antenna performance, affecting radiation efficiency, bandwidth, and biocompatibility. This study aims to construct and optimize microstrip patch antennas operating at 1 THz to determine which substrate is best suited for biological sensing and imaging applications. This study also aims to develop a comparative understanding of the impact of substrate dielectric characteristics on antenna performance and their suitability for integration into sixth-generation (6G)-enabled healthcare systems. Methods: CST Microwave Studio was used to model and simulate several THz microstrip patch antennas. A 50-Ω waveguide port was used to excite each antenna, and open boundary conditions were used to simulate free-space propagation. Several substrate materials, such as polyimide, FR4, Rogers RT/Duroid 5880, gallium arsenide (GaAs), and silicon arsenide (SiAs), were selected for comparative analysis of THz antenna performance. To assess return loss, gain, directivity, bandwidth, and radiation efficiency, frequency sweeps were conducted over 0.5–1.5 THz. Finding the substrate material with the best trade-offs between electrical and biological compatibility was the primary goal of the comparative investigation. Results: According to simulation data, polyimide and Rogers RT/Duroid 5880 substrates outperformed FR4, GaAs, and SiAs in terms of antenna performance. With gain values of approximately 5 dBi at 1 THz, these materials demonstrated improved radiation efficiency, a wider impedance bandwidth, and minimum return loss (<−30 dB). In on-body designs, polyimide offers additional benefits, such as flexibility, low dielectric loss, and consistent responsiveness, making it particularly suitable for wearable biomedical devices. The investigation confirmed that impedance matching and the overall radiation behavior are significantly influenced by the substrate’s dielectric constant and loss tangent. The findings indicate the promise of THz antennas for high-speed wireless communication, noninvasive diagnosis, and real-time biological sensing in healthcare settings. Conclusions: This study offers a methodical comparison of THz patch antennas made of various substrate materials for biomedical imaging and sensing. According to the results, polyimide and Rogers RT/Duroid 5880 are the most effective substrates because they provide the best possible balance of biocompatibility, wide bandwidth, and high gain. The integration of these materials into future implantable and wearable medical systems based on THz shows excellent promise. For 6G communication-enabled healthcare networks and next-generation biomedical equipment, the study advances the creation of high-performance antennas. Future work includes exploring flexible and miniature antenna topologies, experimental validation of the proposed designs, and evaluating real-time performance in biological environments.