Abstract: A Huygens lens is disclosed. The Huygens lens includes a substrate of a dielectric material, the substrate having a first substrate surface and a second substrate surface opposing the first substrate surface. The Huygens lens includes first conductive elements disposed on the first substrate surface and second conductive elements disposed on the second substrate surface. The second conductive elements are electrically insulated from the first conductive elements by the substrate. The first conductive elements and the second conductive elements form an array of a plurality of unit cells, the array having a concentric phase distribution, each of the plurality of unit cells being operable within a range of frequencies, the range of frequencies including at least a part of a W-band of an electromagnetic spectrum.

Abstract: A contamination sensor for a gas turbine engine is disclosed herein. The contamination sensor is made of a selected composition of material and includes a base alloy, an alloy for improving oxide formation, and at least one element from the transition metal group. The composition of the contamination sensor can be adjusted to react with specific contaminants at specific temperature ranges.

Abstract: A contamination sensor for a gas turbine engine is disclosed herein. The contamination sensor is made of a selected composition of material and includes a base alloy, an alloy for improving oxide formation, and at least one element from the transition metal group. The composition of the contamination sensor can be adjusted to react with specific contaminants at specific temperature ranges.