Abstract: An antenna circuit, a method of manufacturing, and a method of operating the same are provided. An antenna member, a first dielectric layer, a top ground plane, a radiating slot ring through the top ground plane, a second dielectric layer, a stripline feed member, a third dielectric layer, and a bottom ground plane are all laminated together within a specified arrangement to form an efficient multi-band micro-strip antenna circuit. A micromachined electromagnetic switch is utilized to alter the length of the antenna member, thereby producing resonant frequencies which correlate with those radiated by the ring slot.

Abstract: A dielectric-loaded, microwave sensor which can detect dielectric coatings, e.g., air, water and ice, on a road surface. The sensor includes an antenna having an aperture and also includes a dielectric member with a lower surface and an upper surface. The dielectric member is arranged with its lower surface across the antenna aperture and the sensor is embedded in a road with the dielectric member's upper surface coplanar with the road's surface. An antenna beam, which is incident upon the dielectric member, generates a return microwave signal which is the composite of microwave reflections from the dielectric member's inner and outer surfaces. Air, water and ice can be uniquely identified by the absence or presence of an amplitude minimum at predetermined frequencies of the return microwave signal. The thickness of an ice coating is determined by observation of the frequency of the amplitude minimum.