RF Bandpass Filter with Reconfigurable In-Band Notches

This paper presents a RF bandpass filter featuring reconfigurable in-band notches embedded within a broad transmission frequency range. The filter design integrates tunable quasi-bandstop sections, allowing independent control over the center frequency and rejection level of each stopband. This dynamic capability facilitates the selection and combination of rejected bands, offering exceptional spectral adaptivity. The filter was designed and simulated using the RF PCB Toolbox from MATLAB, incorporating specific parameters such as substrate material, lumped elements, and precise geometric configurations. The filter operates over a bandwidth from 0.7 GHz to 1.2 GHz. To further validate the design, a prototype with two in-band second-order stopbands was manufactured and measured. This innovative filter concept provides a versatile and adaptable solution for interference mitigation, showing significant promise for advancing RF communication systems across various applications.