PCB-Covered Cavity Filter for Fine RF Frequency Band Tuning

The patent implements a movable tuning electrode that can be adjusted after assembly to change the capacitance between the tuning electrode and resonance elements. This dynamic adjustment mechanism allows frequency band tuning without complex manufacturing processes, as the electrode position can be modified post-assembly to achieve desired frequency characteristics.

The patent changes the electrical parameter (capacitance) by adjusting the physical position of the tuning electrode relative to the resonance elements. By varying the distance and overlap area between electrodes, the capacitance value changes, thereby tuning the resonant frequency of the cavity filter without requiring complex manufacturing variations.

The tuning electrode is designed to be movable along the resonance element, allowing post-assembly frequency adjustment. This simple mechanical movement provides a straightforward method to correct manufacturing tolerances without introducing complex adjustment mechanisms.

The electrode structure is segmented into fixed parts and movable tuning parts, allowing independent adjustment of the tuning electrode position. This segmentation enables simple post-assembly frequency tuning by moving only the relevant electrode segment without affecting other parts of the filter.

The tuning electrode is strategically positioned to interact only with specific resonance elements that require frequency adjustment. This localized interaction allows frequency selectivity improvement without adding extensive electrode structures throughout the entire filter, thereby minimizing additional electrical loss.

The tuning mechanism uses simple electrode patterns that replicate standard PCB trace geometries, allowing implementation with conventional manufacturing techniques. This approach avoids complex electrode structures that would increase electrical loss while achieving the desired frequency tuning capability.