Bandpass Filter at 5 GHz with Reconfigurable Bandwidth Using Integrated ScDDAs

This paper presents a reconfigurable bandpass filter using semi-conductor distributed doped areas (ScDDAs) as active elements. The active and the passive parts are designed in the same way on a silicon substrate in microstrip technology. The ScDDAs are able to commute from quarter-wavelength short-circuited stubs to half-wavelength open-ended ones. This co-design method offers a great design flexibility and makes it possible to integrate the active elements in the substrate. In this paper, a two-pole bandpass filter is synthesized at 5 GHz with a 30 % bandwidth in the ON-state (when the stubs are short-circuited) and a 24 % bandwidth in the OFF-state (when the stubs are terminated by an open-circuit). The synthesis is detailed and the simulation and measurement results presented. A good fitting is obtained for these results proving the viability of such an approach.