Ferdows B. Zarrabi

Miniaturization of terahertz (THz) absorbers is crucial for advancing compact and efficient electromagnetic (EM) devices. This study investigates the impact of various spoof plasmon topologies T-slot, grating, and L-slot on the miniaturization and performance of THz metamaterial absorbers (MAs). The proposed designs utilize dual-ring and single-ring gold structures on a quartz spacer. Our structures demonstrate up to 15% size reduction while maintaining high absorption rates (96%–98%). The L-slot topology exhibits optimal performance with absorption peaks at 0.758 and 0.984 THz (dual ring) and 1.00 THz (single ring), compared to the conventional design’s 0.77-/1.15- and 1.14-THz resonances, respectively. Comprehensive analyses reveal that spoof structures significantly alter phase response, modify group delay characteristics, and enhance electric field distribution uniformity across the resonator surface. The coupled mode theory (CMT) model accurately predicts these behaviors with parameters extracted from simulation results.

THz antenna with wide bandwidth and high Q-factor is interesting for various application including 6G application and THz sensing and controlling the surface current of the antenna is known as a technique for bandwidth enhancement. The slot antenna with metasurface is a good candidate for this aim. In this research, we have suggested a multilayer slot antenna with metamaterial load to provide wide bandwidth which covers the 0.38 to 0.57 THz with bandwidth of 40%. The metamaterial loads make various paths for the current on the surface of the antenna that makes possible achieving the wider bandwidth. The proposed antenna has gain of 4 dBi. To achieve higher bandwidth the dielectric silicon (Si) load is placed over the metasurface. The result shows that the height and form of the Si element can impact the bandwidth of the antenna. To modify the results of the antenna, the shape, height and width of the dielectric load over the antenna is examined. The antenna bandwidth is enhanced more than 100% and it covers 0.371 to 0.616 THz with 49% bandwidth. The proposed antenna is simulated with full wave time domain technique of FIT (finite integrated technique).

THz spectrum is one of the safest areas of light for the body which can be considered in biomedical sensing applications in the human body and can be utilized for high sensitivity detection. In this paper, a THz antenna with a single negative (SNG) load is developed for early cancer detection application. The SNG load is useful to increase the gain and efficiency of the antenna. The primary antenna has a circular slot on the ground plane. Metamaterial element is placed on the cylindrical dielectric. The total size of the antenna is 400 × 400 μm ² and the loss-less quartz substrate is used to design the proposed antenna. In addition, the SNG load provides dual-band characteristics, and the proposed antenna covers 0.85 and 1 THz with high directivity and efficiency which is more than 90%. The achieved results proved that the antenna has higher sensitivity at a lower frequency. Moreover, we showed the proposed dual-band antenna can be used to increase the sensing accuracy of the device to detect the progress of cancer in a specific sample.