Compact Wideband Reflective/Absorptive Bandstop Filter With Multitransmission Zeros

Kong, Mengdan; Wu, Yongle; Zhuang, Zheng; Liu, Yuanan; Kishk, Ahmed A.

doi:10.1109/tmtt.2018.2886847

Cited by 35 publications

(19 citation statements)

References 22 publications

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“…The ripple bandwidth BW r and hence the cut-off frequency f 1 of the prototype filter can be calculated from BW 3dB [37]. Initial parameters of the absorptive stub circuit (Z a , Z b , Z c ) are then determined by (1), (9), (10), and (11). For simplicity, the resistor R can be set to be the same with the termination reference impedance Z 0 .…”

Section: Design Proceduresmentioning

confidence: 99%

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Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-Band Rejection

Liu

2020

IEEE Access

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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 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-ofband 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.

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Section: Design Proceduresmentioning

confidence: 99%

“…Several reflectionless bandstop filter designs have been reported based on lossy resonators [6]- [11], the bridge-T structure [12], and the complementary diplexer architecture [13]. Essentially, directional filter topologies are used to implement reflectionless bandpass filters [14]- [16].…”

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confidence: 99%

Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-Band Rejection

Liu

2020

IEEE Access

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“…Low-Q lossy resonators are also used to achieve either one-port absorption [18]- [20] or symmetrical two-port absorption [21]- [25] for bandstop filters. Quasi-Gaussian lowpass filter prototypes are reported with both ports reflectionless because of the lossy components in the circuit [26], [27].…”

Section: Introductionmentioning

confidence: 99%

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

Liu

2020

IEEE Trans. Microwave Theory Techn.

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In this paper, we present the first demonstration of distributed and symmetrical all-band quasi-absorptive filters that can be designed to arbitrarily high orders. The proposed quasi-absorptive filter consists of a bandpass section (reflective-type coupled-line filter) and absorptive sections (a matched resistor in series with a shorted quarter-wavelength transmission line). Through detailed analysis, we show that the absorptive sections not only eliminate out-of-band reflections but also determine the passband bandwidth. As such, the bandpass section mainly determines the out-of-band roll-off and the order of the filter can be arbitrarily increased without affecting the filter bandwidth by cascading more bandpass sections. A set of 2.45-GHz 1-, 2-, and 3-pole quasi-absorptive microstrip bandpass filters are designed and measured. The filters show simultaneous input and output absorption across both the passband and the stopband. Measurement results agree very well with the simulation and validate the proposed design concept.

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“…In practical circuit design, it is impossible to make RL/S 11 equals infinity, however, it is feasible to enhance the attenuation of S 11 for reducing the reflection to the source. The reflectionless filters [1][2][3][4][5][6][7][8] have been overlooked in the past time until recent years they obtain more and more attention.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Absorption Reflectionless Bandstop Filter and Its Design Using Multi-Layer Self-Packaged SCPW

Xiao

2020

IEEE Access

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Compact Wideband Reflective/Absorptive Bandstop Filter With Multitransmission Zeros

Cited by 35 publications

References 22 publications

Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-Band Rejection

Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-Band Rejection

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

Synthesis of Absorption Reflectionless Bandstop Filter and Its Design Using Multi-Layer Self-Packaged SCPW

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