Abstract: A lightweight phased array antenna systems that is conformable to an aircraft fuselage combines air-filled cavity-backed slots with printed circuit elements for operation in two or more frequency bands. The printed circuit elements are separated from a conductive ground plane in which the slots are cut by a dielectric honeycomb material. The slots and printed circuit elements are individually excitable by a multiband feed network and transmit/receive modules for operation in the UHF band and S band or L band, respectively.

Abstract: An antenna having decreased sidelobes relative to the mainlobe. In the preferred embodiments, the antenna reduces sidelobes by using the sidelobes within an array to cancel the sidelobes of a corresponding, symmetrically related, array.

Abstract: A method for determining the phase delay of microwave energy passing through a dielectric material, and for determining values related to the dielectric constant for microwave circuit boards. Phase delay is determined by positioning a pair of transducers adjacent different surfaces of the dielectric material, and injecting microwave energy at a certain frequency along a path through the material from the first transducer to the second transducer. The frequency of microwave radiation is that frequency at which S.sub.11 and S.sub.22 for the transducers are both less than a selected amount. Where the dielectric material is a conductively surfaced microwave circuit board, the path through the material is from one edge of the board to another edge through the plane of the board.