Band-Pass Tunable Ferroelectric Filter Based on Uniplanar Dielectric Resonators

An X-band 2-pole filter based on uniplanar dielectric resonators (UPDR) with ferroelectric tuning was designed and fabricated. UPDRs were chosen because of their high Q-factor, the rarefied spectrum of resonance mode frequencies, simplicity of manufacture and the convenience for integrating a ferroelectric tuning varactor. The analytical description of the filter response is presented and good agreement between simulated and measured experimental data is demonstrated. At a frequency of ~10.5 GHz the filter displayed insertion losses not more than S₂₁ = -3.5 dB in the bandwidth Deltaf 110 MHz. The frequency of tuning was DeltaF 420 MHz.