QMSIW-Based Slot Antenna for Tumor Sensing Applications in Breast Phantoms

A compact and lightweight Quarter Mode Substrate Integrated Waveguide (QMSIW) cavity-backed slot antenna is proposed as a near-field microwave resonant sensor for breast tumor detection, operating around the ISM frequency band. The proposed design is validated using two different feeding techniques: probe feed and microstrip line feed. When placed in proximity to breast tissues exhibiting abnormalities in dielectric properties, the sensor demonstrates exceptional sensitivity in its resonance characteristics. To tune the resonant frequency of ISM band, a slot is precisely etched into the antenna patch near the magnetic walls. The QMSIW cavitybacked antenna was initially designed to operate at 2.7 GHz, and the incorporation of the slot plays a crucial role in miniaturization while maintaining the sensor's sensitivity. For performance evaluation, the sensor is first tested with a healthy breast phantom, followed by a systematic variation of the tumor's position and radius. A significant contrast between healthy and malignant tissues is observed in both simulated and measured reflection coefficients, demonstrating the sensor's effectiveness in breast tumor detection.