Affiliation(s):
School of Information Science and Technology, and the Research Center for Intelligent Information Technology, Nantong University, Nantong 226019, China
Abstract: A compact input-reflectionless balanced bandpass filter (BPF) with flexible bandwidth (BW) using a three-line coupled structure (TLCS) is presented in this paper. For the differential mode (DM), the TLCS is applied to realize the bandpass response; meanwhile, the coupled-feed line of the TLCS is reused in the input absorptive network. This design shows a good fusion of the bandpass and absorptive sections, effectively reducing the circuit size, and the BW of the two sections that can be controlled separately results in a flexibly controllable DM and BW of the proposed input-reflectionless balanced BPF. Additionally, detailed analyses of the ratio of the two-part BWs are given for the first time, which is vital for the passband flatness and reflectionless feature. Accordingly, in the codesign of this work, the input-reflectionless DM bandpass response can be optimized easily, while wideband common-mode (CM) absorption is also achieved by the input absorptive network. To verify the design method, a prototype with a compact size (0.52λ×0.36λ) is designed and measured in the 0-7.0 GHz range. The DM center frequency (f0) is located at 2.45 GHz with a measured 3 dB fractional bandwidth of 31.4 %. The simulated and measured results with good agreement are presented, showing good performance, e.g., low insertion loss (0.43 dB), wide upper stopband for the DM bandpass response (below 20 dB up to 2.72f0), and wideband DM reflectionless and CM noise absorption (absorptive bandwidth of 285.7 %).
Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article
Reference
Open peer comments: Debate/Discuss/Question/Opinion
Open peer comments: Debate/Discuss/Question/Opinion
<1>