Abstract: The radar cross section (RCS) of a vehicle/antenna combination is reduced by using an antenna and ground plane which are of substantially the same area, and using a frequency selective surface (FSS) in the regions on the periphery of the ground plain where the FSS is designed to be transparent and thereby pass out-of-band frequencies, while reflecting one or more operating frequencies of the antenna. A multilayer absorber below the FSS absorbs the out-of-band frequencies that a larger ground plane may have otherwise reflected to the body of the vehicle to which the antenna is mounted.

Abstract: The suprastructure over a substrate integrated waveguide (SIW) can provide for beam scanning utilizing a reconfigurable metasurface. The reconfigurable metasurface will have a plurality of PIN diode arrays that can be turned ON and OFF. In one design, the length of the reconfigurable metasurface is effectively enlarged or reduced in size to achieve beam scanning. In another design the tilt angle of the reconfigurable metasurface is adjusted to achieve beam scanning. The suprastructure also can be modified with metallic offset wings, where two or more pairs of offset wing can form a horn shaped element. The presence of the wings or horn, as well as control of the size and number of the wings can improve the gain of the SIW. These two suprastructure improvements may be used in combination, and they may be used over classical slotted SIWs or over an SIW with curved sections between consecutive slots.

Abstract: Subreflectors for frequency-reuse types of satellite communication system which cover the S and C bands take the form of a three-dimensional waveguide with cross dipoles on each end, where each branch of each dipole is electrically connected by conductor that passes through the center of a substrate that fills the volume of the waveguide. The frequency selective surface sub-reflector is configured to permit the S-band antenna to transmit therethrough with an insertion loss of less than 0.5 decibels, and to reflect transmissions of the C-band antenna with transmissions through the frequency selective surface sub-reflector being less than 15 decibels.