Error analysis on single sideband modulator

Abstract

mm, which can be regarded as an open stub, whereas the one at 6.65 GHz is owing to the parallel coupling between the two MMRs. It is interesting to note that both the simulated and measured return-loss curves show four distinct reflection zeros, the first (last) two of which pertain to the mode splitting due to the coupling between the two MMRs that are in /4 (/2) resonance. The presence of the reflection zeros thus enhances the transmission, leading to a relatively wide and flat passband. Also shown in Figure 6 is the measured group delay, which is less than 0.56 ns in the passband. The maximum in-band group-delay variation of 0.11 ns in conjunction with the flat insertionloss response in the passband implies the good linear characteristic of the proposed wideband BPF. Presented in Figure 7 is the photograph of the fabricated wideband BPF, which measures only 6.91 ϫ 11.71 mm 2 . CONCLUSIONA wideband BPF consisting of two MMRs has been proposed and implemented in this paper. The novel MMR was formed by combining two /4 SIRs, resulting in /4 resonance at one frequency and /2 at the other. By locating the fundamental resonant frequency of the inherent /4 SIR and that of the embedded /2 SIR in the designated passband of the proposed BPF, we have successfully realized a wideband BPF. The fabricated BPF was demonstrated to have a large passband bandwidth of 1:2.2 with an insertion loss of less than 0.86 dB and a small group-delay variation of not more than 0.11 ns in the passband.