A 3D-printed circularly polarized cavity-based slotted waveguide antenna for a kidney cancer detection application

This paper presents a novel circularly polarized (CP) slot antenna based on a waveguide cavity resonator for kidney cancer detection applications. The cavity is coupled to the input port via a capacitive iris, ensuring strong coupling and improved impedance matching compared to conventional waveguide slot antennas. An L-shaped radiating slot, formed by two orthogonal linearly polarized (LP) slots, is etched into the broad wall of the cavity to generate CP radiation. The axial ratio bandwidth (ARBW) is enhanced by optimizing the slot dimensions. To validate the predicted results, a 3D-printed prototype was fabricated and tested. The measured 10- dB fractional bandwidth (FBW) is 7.4 % at the center frequency (f0) f0 = 10 GHz, while the 3- dB ARBW and peak gain are 7.0 % and 7.5 dBic, respectively. The detection capability of the proposed antenna is evaluated in a modeled measurement system, revealing a calculated sensitivity of 0.175 GHz/RIU at f0 =10 GHz. Furthermore, the antenna exhibits a resonance frequency shift of 0.21 GHz when tested with renal cancer cells, distinguishing them from normal cells. These findings demonstrate that the proposed antenna effectively distinguishes between normal and cancerous kidney cells, making its potential as a good candidate for kidney cancer detection.