Filter design aspects in analog receiver front-ends for frequency scanning applications

In this paper, the design of filter components for a frequency scanning receiver RF front-end is described. The front-end is an integral component of a multichannel scanning and DF (direction finding) system. It covers a broad frequency range of VHF (very high frequency) and UHF (ultra high frequency) from 30MHz to 3GHz and comprises a scalable multichannel digital receiver as well as a hybrid synchronizable double superheterodyne analog receiver approach with direct sampling path. Focus is put on optimizing cost and benefit by balancing system and filter design efforts and choosing efficient technologies for filter implementation using COTS (commercial off-the-shelf) components. The design and implementation of a reconfigurable preselection filter bank, a coupled line resonator IF (intermediate frequency) filter, and a COTS IF filter bank are presented. The performance of these modules is demonstrated by measurement and simulation results.