Transmission Zeros of Trisection and Quadruplet Bandpass Filters With Mixed Cross Coupling

2021 ◽  
Vol 69 (1) ◽  
pp. 89-100
Author(s):  
Alexander Zakharov
Keyword(s):  
Cross Coupling ◽  
Bandpass Filters ◽  
Transmission Zeros

Two- and Four-Pole Multilayer SIW Filter with High Selectivity and Higher-Order Mode Suppression

Frequenz ◽  
2019 ◽  
Vol 73 (5-6) ◽  
pp. 209-217 ◽  
Author(s):  
Dinghong Jia ◽  
Quanyuan Feng ◽  
Qianyin Xiang
Keyword(s):  
High Selectivity ◽  
Filter Design ◽  
Design Method ◽  
Single Layer ◽  
Cross Coupling ◽  
Bandpass Filters ◽  
Coupling Scheme ◽  
Transmission Zeros ◽  
Compact Size ◽  
Spurious Mode

Abstract This letter presents an approach to design two-pole source-load coupling and four-pole cross-coupling substrate integrated waveguide (SIW) bandpass filters based on multilayer process. Utilizing the field distribution, the vertical magnetic and electric coupling of fundamental mode is designed by suppressing the first spurious mode. Then, source-load and cross-coupling schemes are realized with controllable features in two-pole and four-pole filters, respectively. The harmonic passband produced by TE102 mode can be suppressed by proper coupling technique enabling the connection with TE102 mode in two- and four-pole filter designs, respectively. Three transmission zeros, which are derived from source-load coupling, are introduced around the passband of two-pole filter to improve its selectivity. In the four-pole filter design, a six-order cross-coupling scheme including source and load produces four transmission zeros around the passband, leading to a sharp selectivity. In addition, another transmission zero is generated at the adjacent location of the passband to improve the out-of-band rejection. Compared with conventional horizontally coupled filters made of single layer, the proposed filters show a compact size. To demonstrate the proposed design method, a two-pole and a four-pole double-layered SIW bandpass filters are fabricated and measured. Measured results show that the proposed filters exhibit high selectivity and good out-of-band rejection, as well as a good agreement between simulated and measured results.

scholarly journals Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-band Rejection

2020 ◽  
Author(s):  
Xiaohu Wu ◽  
Yingsong Li ◽  
Xiaoguang Liu
Keyword(s):  
Impedance Matching ◽  
Cross Coupling ◽  
Bandpass Filters ◽  
Output Analysis ◽  
Design Concepts ◽  
Frequency Responses ◽  
Transmission Zeros ◽  
Prior Art ◽  
Coupled Lines ◽  
Stopband Attenuation

High-order quasi-reflectionless bandpass filters with improved passband flatness and good impedance matching both in-band and out-of-band are proposed in this work. The proposed design consists of conventional coupled-lines bandpass sections loaded with the presented absorptive stubs at the input and output. Analysis shows that the absorptive stub is equivalent to a 2-pole bandstop filter. Compared to the prior art, the higher-order nature of the presented absorptive stub enables a flatter passband and better out-of-band rejection. The overall filter stopband attenuation can be readily improved by increasing the number of coupled-lines sections without altering the passband responses. Furthermore, cross-coupling between the two absorptive stubs can be used to improve the out-of-band rejection by introducing two transmission zeros without affecting the absorption characteristics. The proposed design concepts are experimentally validated by the design and fabrication of a set of 2.4-GHz 1-, 2-, and 3-pole microstrip quasi-reflectionless bandpass filters. Measured frequency responses of these filters closely match those of the simulation.

scholarly journals Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-band Rejection

2020 ◽  
Author(s):  
Xiaohu Wu ◽  
Yingsong Li ◽  
Xiaoguang Liu
Keyword(s):  
Impedance Matching ◽  
Cross Coupling ◽  
Bandpass Filters ◽  
Output Analysis ◽  
Design Concepts ◽  
Frequency Responses ◽  
Transmission Zeros ◽  
Prior Art ◽  
Coupled Lines ◽  
Stopband Attenuation

High-order quasi-reflectionless bandpass filters with improved passband flatness and good impedance matching both in-band and out-of-band are proposed in this work. The proposed design consists of conventional coupled-lines bandpass sections loaded with the presented absorptive stubs at the input and output. Analysis shows that the absorptive stub is equivalent to a 2-pole bandstop filter. Compared to the prior art, the higher-order nature of the presented absorptive stub enables a flatter passband and better out-of-band rejection. The overall filter stopband attenuation can be readily improved by increasing the number of coupled-lines sections without altering the passband responses. Furthermore, cross-coupling between the two absorptive stubs can be used to improve the out-of-band rejection by introducing two transmission zeros without affecting the absorption characteristics. The proposed design concepts are experimentally validated by the design and fabrication of a set of 2.4-GHz 1-, 2-, and 3-pole microstrip quasi-reflectionless bandpass filters. Measured frequency responses of these filters closely match those of the simulation.

A Simple Compact Microstrip Wideband Bandpass Filter

2013 ◽  
Vol 760-762 ◽  
pp. 236-240
Author(s):  
Jian Kang Xiao ◽  
Wu Zhu ◽  
Yong Li ◽  
Wei Zhao
Keyword(s):  
Bandpass Filter ◽  
Bandpass Filters ◽  
Size Reduction ◽  
Transmission Zeros ◽  
Good Agreement

Two wideband bandpass filters with miniature size and wide stopband are proposed by using cascaded U-shaped resonators. The filters exhibit bandwidths of 31.1% and 28.8% at about 5.3GHz and 5.6GHz, respectively. Both designed filters have simple structures and compact sizes, wide passband, excellent out-band performance with wide lower and upper stopbands, and a pair of transmission zeros on both sides of passband. The new designs have evident circuit size reduction compared with relative reports. A wideband microstrip BPF is fabricated and measured, and the measurement exhibits good agreement with the prediction.

Two Types of Trisection Bandpass Filters With Mixed Cross-Coupling

2018 ◽  
Vol 28 (7) ◽  
pp. 585-587 ◽  
Author(s):  
Alexander Zakharov ◽  
Sergii Rozenko ◽  
Michael Ilchenko
Keyword(s):  
Cross Coupling ◽  
Bandpass Filters

Selectivity improved directional filters using cross-coupling introduced transmission zeros

2019 ◽  
Vol 33 (16) ◽  
pp. 2126-2141
Author(s):  
Jakub Sorocki ◽  
Kamil Staszek ◽  
Ilona Piekarz ◽  
Slawomir Gruszczynski ◽  
Krzysztof Wincza
Keyword(s):  
Cross Coupling ◽  
Transmission Zeros ◽  
Directional Filters

scholarly journals Compact Ultra-Wideband Bandpass Filters Achieved by Using a Stub-Loaded Stepped Impedance Resonator

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
Min-Hang Weng ◽  
Fu-Zhong Zheng ◽  
Hong-Zheng Lai ◽  
Shih-Kun Liu
Keyword(s):  
Resonant Mode ◽  
Bandpass Filters ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Transmission Zeros ◽  
Notch Band ◽  
Resonant Modes ◽  
Attenuation Level ◽  
Stepped Impedance Resonator ◽  
5 Ghz

In this paper, we develop a bandpass filter using a stub-loaded stepped impedance resonator (SLSIR) and calculate the even and odd resonant modes of this type of resonator using the input impedance/admittance analysis. In this study, two impedance ratios and two length ratios are operated as the design parameters for controlling the resonant modes of the SLSIR. Several resonant mode variation curves operating three resonant modes with different impedance ratios and two length ratios are developed. By tuning the desired impedance ratios and length ratios of the SLSIRs, compact ultra-wideband (UWB) bandpass filters (BPFs) can be achieved. Two examples of the UWB BPFs are designed in this study. The first example is UWB filter with a wide stopband and the second one is dual UWB BPF, namely, with UWB performance and a notch band. The first filter is designed for a UWB response from 3.1 to 5.26 GHz having a stopband from 5.3 to 11 GHz, with an attenuation level better than 18 dB. The second filter example is a dual UWB BPF with the frequency range from 3.1 to 5 GHz and 6 to 10.1 GHz using two sets of the proposed SLSIR. The measured results have insertion loss of less than 1 dB, and return loss greater than 10 dB. Furthermore, the coupling structures and open stub of the SLSIR also provide several transmission zeros at the skirt of the passbands for improving the passband selectivity.

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