Abstract: The present invention is related to a method in the design of constellation of non-geostationary satellites for broadband multimedia communications. A broadband multimedia satellite communication system based on the present invention will not have interference problems with the GEO satellites and terrestrial communications. Users of the system will be able to use very low cost simple automatic tracking antenna to access broadband multimedia services anywhere around the world.

Abstract: A high performance phased array antenna system for receiving satellite communication signals, with a structural top layer formed as a perforated plate (or solid plate made of very low loss plastic material), a middle layer functioning as the single layer antenna aperture layer, preferably in the form of a single layer printed circuit board on which is formed an array of antenna elements and plurality of stripline feed network circuits, each combining in-phase outputs from several adjacent antenna elements, the bottom layer functioning as the ground plane for the antenna aperture layer and also including a single level waveguide combining network for combining in-phase outputs from stripline feed network circuits electromagnetically coupled to respective transition probe holes of the waveguide combining network. Each antenna element is preferably a dual polarization octagonal patch antenna element disposed on a common surface of the antenna aperture layer.

Abstract: A cavity-backed slot array antenna is provided which offers wide frequency bandwidth in a conformal structure and further offers forward horizon coverage and wide angle beam scanning. The slot array antenna has a plurality of cavity-backed slot arrays. Each array contains a plurality of conductive cavities and radiating slots. The conductive cavities have varying size length and width in accordance with a log-periodic scale and, some conductive cavities have a maximum constant width. The slots are preferably formed in a folded configuration extending along a substantial portion of the width of the conductive cavity and further extend along a portion of the length of the conductive cavity one or more times. For a conductive cavity at maximum width, the corresponding slots are further extended in the effective overall length so as to further extend the frequency bandwidth, while maintaining a compact antenna structure.

Abstract: A dual cavity-backed slot antenna is provided which exhibits a relatively wide frequency bandwidth and dual resonant frequency capabilities. The antenna includes a first substrate board having a bottom conductive surface and a top surface with a conductive feedline etched thereon. A second substrate board is further included having a bottom surface which is bonded to the top surface of the first substrate board. The second substrate board has a top conductive surface with radiating slots etched thereon. First and second conductive cavities are provided which extend from the top conductive surface of the second substrate board to the bottom conductive surface of the first substrate board. Each of the first and second cavities enclose at least one of the radiating slots.

Abstract: A printed circuit cavity-backed crossed-slotted conductive element having two legs of each slot coupled by stripline feeders to a radio communications device. The feeders supply the radio frequency signal with a 180 degree phase shift in order to cancel cross-coupling from one leg to another around the intersection. The conductive element and the stripline feeders are mounted on separate substrates which are attached together with other elements to provide shielding and mechanical protection. The crossed-slot design reduces space and structure required for a mobile application while achieving good performance. When mounted in an array, the crossed slot antennas may be directionally tuned to a specific satellite/frequency/direction via pin diode phase shifters.