Near-Field Microwave Loop Array Sensor for Breast Tumor Detection

In this work, we propose the use of loop antenna arrays excited by a single port as a microwave sensor for near-field microwave breast tumor detection. The proposed sensor has a high sensitivity to detect an abnormality in the dielectric properties of breast tissues. The existence of the breast tumors is detected by estimating the variations in the response of the reflection coefficient of the sensor for both tumours and healthy cases. The developed sensor comprises 4-element identical loop antenna array fed with a single port, the use of antenna array enlarges the sensitivity area as compared to a single element resulting in better detection of tumors located deeply inside breast tissues. Numerical simulations have been conducted using a numerical breast model with and without tumor cells placed in the near-field of the sensor. The sensor is capable of detecting a breast tumor inserted at five different locations and with various sizes. An experimental validation was conducted using a glass box filled with vegetable oil and metallic spheres that resembles healthy and tumourous breast tissues, respectively. The simulation and experimental results show that the array sensor has a high sensitivity for detecting a metallic sphere placed at five different locations inside a dielectric medium as well as detecting variable sizes of the metallic spheres.