Abstract: A method and apparatus for providing a high impedance structure or surface comprising at least one electrically conductive wire forming at least one elongate wire spiral, the at least one elongate wire spiral being defined by a plurality of spirals of said at least one wire, the spirals having a pitch and being spaced apart along a major axis of said elongate wire spiral; and an arrangement for varying the pitch of the spirals of said at least one wire to thereby tune the impedance of said tuneable impedance structure. An embodiment useful as an antenna aperture to steer a radio frequency beam having two different polarizations is disclosed.

Abstract: An electromagnetic wave detecting device includes a dipole antenna having a pair of disjointed arms for receiving an electromagnetic wave and a thermocouple having a first and a second leg of two dissimilar conductors, for detecting the electromagnetic wave received by the arms of the antenna.