A compact hairpin bandpass filter on high-permittivity dielectrics using A tape-casting technique

By using high-permittivity dielectrics, bandpass filters can be miniaturized. A hairpin-line filter based on high-permittivity dielectrics is proposed in this study. Ba₂Ti₉O₂₀, with high dielectric constant, low loss, and stable temperature is available for the dielectric resonator and is adopted as a material in the fabrication of high-permittivity ceramic substrates. A tape-casting technique is employed to produce thin and flat Ba₂Ti₉O₂₀-based ceramic substrates. The center frequency of the fabricated bandpass filter is 5.75 GHz and the bandwidth is 742 MHz. The measured insertion and return losses of the filter are -1.34 and -12 dB, respectively. The measured response of the fabricated filter is in, agreement with the simulated results.