A Reconfigurable Dielectric-Loaded Millimeter-Wave Waveguide Bandpass Filter Based on Customized 3D-Printing Vanadium Dioxide Filament

A reconfigurable millimeter-wave waveguide bandpass filter utilizing 3D-printed free-form dielectric resonators is presented in this paper. The dielectric resonators are fabricated using novel customized reconfigurable 3D-printing filaments, composed of thermoplastic copolyester and vanadium dioxide nanoparticles. To evaluate thermal reconfigurability of the filament, the dielectric constant and loss tangent of the proposed filament have been characterized at W-band at both room temperature and phase transition temperature, with dielectric constant changes observed clearly. The proposed waveguide bandpass filter exhibits a center frequency of 23.63 GHz at room temperature, which shifts to 23.03 GHz when heated to the phase transition temperature. Experimental results demonstrate excellent agreement with simulations, validating the proposed design and implementation methodology.