Noninvasive Microwave-Multielement Sensor for Breast Phantoms Analysis and Tumor Detection

This article proposes a microwave sensor for breast phantom analysis and tumor detection. The sensor is developed on the small-size (
$25\times25$
mm2) low-cost RT/duroid 5880 substrate. The structure of the proposed sensor is made up of four sensory elements. The sensor performance is experimentally validated by the evaluation of the S-parameters and radiation patterns. The proposed sensor has a 2–30-GHz-wide operating bandwidth, lower mutual coupling (
${S} _{{21}} \le -30$
dB) between the elements, and offered a desirable directional radiation pattern. Four types of breast phantoms are mimicked: normal phantom, phantom with 3-, 5-, and 10-mm tumor. Developed phantoms have experimented with the proposed sensor and tumor identification is carried out. Measurement of the S-parameters, i.e., reflection coefficients (
${S} _{{11}}$
,
${S} _{{22}}$
,
${S} _{{33}}$
,
${S} _{{44}}$
) and mutual coupling coefficient (
${S} _{{21}}$
,
${S} _{{31}}$
,
${S} _{{41}}$
) with and without tumor phantom is executed. A large difference in the peak value of the S-parameters results for normal and malignant phantoms is observed over the 2–20-GHz frequency range. Reflection results from data are further processed through principal component analysis (PCA) to better visualize the difference between normal and malignant phantoms. Obtained PCA results exhibited a significant difference between normal and malignant phantoms. Specific absorption rate (SAR) analysis is also performed to separate normal and malignant phantoms. The proposed approach is a noninvasive, low-cost modality and can analyze the phantoms for tumor detection.