Compact E-plane varactor -tuned bandpass filters

This paper presents electromagnetic simulation of a varactor-tuned E-plane waveguide band-pass filter. Silicon varactor diodes which can operate through X band are placed between gaps in the centre fins of an E-plane extracted pole section to provide tuneability for the filter structures. The simulation of the filter was carried out by CST Microwave Studio with the diodes being modelled by its Spice model in CST Design Studio. Tuning range of 280 MHz is achieved.