A compact Ku‐band MMIC subharmonic image rejection mixer using an active filter

Abstract

BPF. A three-stage BPF is fabricated in order to further improve the skirt at the outband performances in both lower and upper stopbands. All design parameters are the same those of the onestage filter except w 3 ϭ 0.1 mm, w 4 ϭ 0.24 mm, and w 6 ϭ 0.23 mm. The total length except 50-⍀ feed line is 23.48 mm. Figure 5 shows the measured and predicted frequency responses of the three-stage BPF. The skirt performance at the outband is sharper than that of the one-stage. Its measured and predicted maximum insertion loss are both less than 2.4 dB and the measured group delay varies between 0.27 and 0.73 ns with a maximum variation of 0.46 ns over the UWB band. CONCLUSIONSIn this letter, a novel UWB BPF using a DUC-EBG unit cell with multiple-mode resonance is presented for size reduction. This proposed filter has been demonstrated by various experiments and analyzed using the equivalent circuit of the DUC-EBG cell. The distributed L-C component values of the DUC-EBG cell are found using curve-fitting with the measured S-parameters. Moreover, a three-stage filter is designed and fabricated to improve the skirt performance. This design is very useful for UWB applications as the compactness is needed. REFERENCES