A Novel Miniaturized Microwave Microstrip Filter Used Cross-Coupled Square Resonators

A novel cross-coupled band-pass filter(BPF)based on the flute resonator is proposed in this paper. Due to the adoption of the same new configuration of coupling coefficient, the distance between the two loops is clearly shortened, which offers BPF an advantage of miniaturization. The configuration is characterized by a higher Q factor by introducing two transmission zeros in the transfer-function. Through the analysis of electromagnetic software CST to achieve the structural parameter of the coupling coefficient of this configuration, the band-pass filter used in K waveband and X waveband are designed in this experiment with dimension of 2.3times2.4 mm
²
and 5.9times5.9 mm
²
respectively. The X-band bandpass filter's insertion loss (IL) of 3.2 dB, and the IL of the out-passband of 25 dB. The result of the experiment agrees well with emulate wave.