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Microwave radar array antennas generally employ a beamformer which functions as the interface between the array elements and the transmitter-receiver, distributing signals to the array elements on transmit, and coherently combining the elemental signal components on receive. A conventional beamformer typically consists of corporate feed manifolds comprised of waveguide or coaxial cables, stripline combiner circuits, etc. These manifolds grow increasingly large and heavy in proportion to the number of elements in the array. Optical bemaformers, which utilize manifolds made up of optical fibers, promise a lightweight and very compact alternative approach. In an optoelectronic implementation the electrical signals are first converted to a modulation on an optical carrier frequency, and then the distribution and combining manifolds are configured with optical fibers. This paper compared conventional and optical implementations for a large, dual band (S and UHF) radar array. A detailed dual band beamformer design is developed for each technology and the two designs are compared with respect to weight, volume and power consuption. Both designs meet the same set of dynamic range, noise figure, bandwidth, power output, and sidelobe weighting requirements.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
