State-of-the-art SAW channelizer for EW receiver application

This paper discusses the implementation of a state-of-the-art, miniaturized SAW channelizer with seven contiguous SAW filters covering the frequency span of 257.5 MHz to 397.5 MHz. The filter bank exhibits time spurious suppression greater than 65 db, noise figure of less than 18 db, and a minimum input third-order intercept of 25 dBm. The noise figure requirement dictates that the SAW filter should have less than 15 dB loss over all conditions and should provide more than 65 dB electromagnetic crosstalk and triple-transit suppression. The SAW filters are fed by a power divider to reduce interaction between filters. The SAW channelizer is fitted in a hermetic, specially-tooled package (3.8 inches×1.7 inch×0.2 inch) to achieve the feed through suppression requirement. Wideband SAW delay lines are generally used in this type of receiver to store the incoming signal while initial frequency classification and other processing functions are performed. This paper also discusses the design of a wideband delay line/amplifier module with greater than 540 MHz bandwidth at a center frequency of 1250 MHz and triple-transit suppression of better than 70 dB