Miniaturized Fully Reconfigurable Bandpass Filter with Automated Varactor Biasing

A miniaturized substrate integrated waveguide (SIW) reconfigurable filter is presented in this paper. The filter is based on quasi-lumped substrate integrated coaxial resonators. Varactors are used as tuning elements to enable a continuous control of all filter parameters. To obtain any targeted response, an automated hardware optimization of the filter is demonstrated based on a single-board computer and a high-voltage varactor driver module. This process enables us to obtain the bias voltages of all varactors for obtaining a particular response. Thus, a twopole filter example, with a compact size of 5.60×5.85 mm
²
has been designed, manufactured and measured, showing different reconfiguration scenarios, both in terms of absolute bandwidth and frequency in the n77 and n78 5G channels.