Frequency Reconfigurable Interdigital Filter Using Semi-conductor Distributed Doped Areas

This paper presents a frequency reconfigurable interdigital filter designed on a semi-conductor substrate. The filter associates parallel-coupled lines and two stubs, where both stubs switch from open-ended to short-ended. Therefore, the reconfigurability is achieved by biasing some Semi-conductor Distributed Doped Areas (ScDDAs), which are N+PP+junctions, working as active elements integrated in the substrate. The design method is based on a co-design of the active and the passive parts in a same time. A two order filter validates the co-design approach from the synthesis to the measurements. The filter resonant frequency commutes from 3.5 GHz to 2.2 GHz.