Wideband Reconfigurable Bandpass-to-Bandstop Filter Based on Embedded Switches on Silicon Technology

This paper proposes a reconfigurable (switchable) bandpass-to-bandstop filter configuration with wideband performances. The suggested configuration is easy to design and implement by just using transmission line sections, avoiding the use of coupled-line stages. The filter is implemented in silicon technology by using embedded switches which are co-designed along with the transmission lines, which prevents the parasitic effects from SMD components and facilitates the integration with other subsystems and the system-on-chip (SoC) implementation. When the embedded switches are Off, the bandstop filter state is obtained leading to a fifth-order and very selective response along with a very broad upper passband. When they are turned On, a third-order bandpass filter response is achieved with one transmission zero. The proposed configuration also allows a good design flexibility between states. To validate the concept, a prototype centered at 3.0 GHz has been designed and implemented to present a 3-dB fractional bandwidth of 75% for both states, showing a good agreement between simulations and measurements.