Affordable Array Antennas for Multiple Satellite Links

For tactical communication systems parabolic antennas can acquire a single satellite but requires complex mechanical structure and control systems. For multiple satellite links, separate antennas are necessary. This consumes valuable area on the ship, and requires more hardware and resources. With the availability of a mature monolithic microwave based Transmit/Receive modules it is now possible to look at alternative concepts. The availability of the T/R modules alone is not sufficient if a low cost shared aperture antenna is to be realized. Innovative front end partitioning and use of other technologies, such as multilayer printed circuit microwave technology or low temperature co-fired ceramics needs to be incorporated. For an antenna to acquire two simultaneous satellite links in the X-band, C-band, and KU-band requires an innovative concept that will compete with the single parabolic concept. It is important to realize that the signal to noise ratio at the input of the antenna, based on a constant power radiated from a distant satellite, is determined by the aperature of the antenna. Any elements introduced behind the antenna aperature, such as filters or amplifiers with a known loss or noise figure, will degrade the subsequent signal to noise ratio. Active phase array radars require solid state T/R modules with high output poster, low noise figure, high third order intercept, and sufficient gain. The T/R module cost is typically 40% of the antenna cost and, therefore, it is important to realize that an innovative concept with an architecture that requires a milumum number of the active components. The Multibeam Array approach proposed under this Phase I SBIR can be utilized for either the narrow or wideband arrays. The capability for changing the array excitation, amplitude, and phase distribution across a particular aperture requires a control circuit, a Sideband power splitter or feed network, and a wideband antenna element. The specific technical objectives of the Phase I SBIR proposed herein examines the critical issues that will make a Multibeam aperature phase array antenna a practical technology. The requirement to operate several systems simultaneously from a conunon aperature can be achieved by using a control circuit at each element. The control circuit consists of an arrangement of a multiplexer, an attenuator, and a phase shifter. The multiplexer is used to partition the aperature into several simultaneously operating antennas. The attenuato