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A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S-parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain.

Surface plasmon resonance (SPR) biosensors based on transition metal dichalcogenides (TMDC) materials have shown improved performance in terms of sensitivity, detection accuracy (DA), and quality factor (QF) over conventional biosensors. In this paper, we propose a five-layers model containing black phosphorus (BP) and TMDC (Ag/BP/WS2) in Kretschmann configuration. Using TM-polarized light at 633 nm, we numerically demonstrate the highest sensitivity (375°/RIU), DA (0.9210), and QF (65.78 1/RIU) reported so far over similar materials. Refractive index (RI) of the coupling prism has also played an essential role in enhancing the performance of these biosensors. The research on TMDC materials is still new, and these materials bring about opportunities to develop a new class of biosensor.

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