Non-invasive antenna sensor for dielectric material identification at a distance

Abstract

A planar leaky wave antenna is used as a non-invasive microwave sensor for dielectric material identification at a distance. The antenna radiation pattern main lobe points to specific angles according to the dielectric material under test, placed above the antenna. In this work, two materials were used, and compared to the antenna with no material under test, namely quartz with a dielectric constant of 3.75 and borosilicate glass with a dielectric constant of 4.5. The antenna sensor described in this work, is designed to operate at 18 GHz and has a total dimension of 150 × 32 mm. The experimental methods used in this work consist of validating the sensor antenna design in Ansys HFSS®, electromagnetic simulation software and comparing simulated results with measured tests performed in an anechoic chamber. Dielectrics are placed over the sensor antenna and measured radiation patterns recorded. The sensor antenna presented displacement in the main lobe of its radiation pattern when in contact with a dielectric under test. In the presence of quartz, the maximum radiation angle is 33°, in the presence of borosilicate glass the angle shifted to 37°.