Tri-band filter with multiple transmission zeros and controllable bandwidths

2014 ◽  
Vol 8 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Qun Li ◽  
Yong-Hong Zhang ◽  
Xin Feng ◽  
Yong Fan
Keyword(s):  
High Selectivity ◽  
Bandpass Filter ◽  
Electrical Coupling ◽  
Resonant Frequencies ◽  
Splitting Technique ◽  
Transmission Zeros ◽  
Band Filter ◽  
Feed Network ◽  
Multiple Transmission ◽  
Good Agreement

This paper presents a compact microstrip tri-band bandpass filter (BPF) using two multimode stepped-impedance resonators (SIRs) with a 0° feed structure. The fundamental odd-mode and even-mode resonant frequencies and the third resonant frequency are utilized to determine the center frequencies of the tri-band filter. The mode-splitting technique is used by combining two SIRs with electrical coupling. Therefore, two modes generate one passband and the bandwidths can be controlled by the electrical coupling strength. The 0° feed network is applied to create one pair of transmission zeros at each side of all the triple passbands, resulting in high selectivity. Finally, a tri-band BPF with the central frequencies of 1.8, 2.4, and 5.8 GHz, and respective fractional bandwidths of 8.9, 12.5, and 5.3% are designed and fabricated. The simulated and measured results show a good agreement.

Multilayer SIW Dual-Band Filters with Independent Band Characteristics and High Selectivity

Frequenz ◽  
2019 ◽  
Vol 73 (9-10) ◽  
pp. 293-300
Author(s):  
Dinghong Jia ◽  
Jianqin Deng ◽  
Yangping Zhao ◽  
Ke Wu
Keyword(s):  
High Selectivity ◽  
Bandpass Filter ◽  
Large Range ◽  
Metal Layer ◽  
Dual Band ◽  
Effective Dimension ◽  
Dual Mode ◽  
Transmission Zeros ◽  
Design Freedom ◽  
Good Agreement

Abstract This work presents an approach to developing dual-mode dual-band substrate integrated waveguide (SIW) bandpass filter based on multilayer process. TE102/TE201 and TE101/TE102 modes are used to feature the two passbands, respectively. To begin with, large range of band location ratios are decided by the effective dimension of the SIW resonator. With reference to the field distribution, independent coupling schemes of the dual-modes are then realized by slots or circular apertures etched on the middle metal layer. It allows to not only introduce a large design freedom of bandwidth but also keep compactness. Finally, source-load and mixed couplings are deployed to produce transmission zeros around the passband in providing a sharp selectivity in the two filters, respectively. The details to independently control the center frequencies and bandwidth of two passbands are also presented. A two-order double-layered and a triple-layered SIW dual-band bandpass filter are prototyped to evaluate the proposed design approach, respectively. Results show a good agreement between simulations and measurements. The proposed filter exhibits flexible design freedom, high selectivity as well as good out-of-band rejection.

scholarly journals High Selectivity Dual-Band Bandpass Filter with Tunable Lower Passband

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Wei-Qiang Pan ◽  
Xiao-Lan Zhao ◽  
Yao Zhang ◽  
Jin-Xu Xu
Keyword(s):  
High Selectivity ◽  
Bandpass Filter ◽  
Bandpass Filters ◽  
Dual Band ◽  
Transmission Zeros ◽  
Resonant Modes ◽  
Novel Method ◽  
Good Agreement ◽  
Tunable Bandpass Filter

This paper presents a novel method to design dual-band bandpass filters with tunable lower passband and fixed upper passband. It utilizes a trimode resonator with three controllable resonant modes. Discriminating coupling is used to suppress the unwanted mode to avoid the interference. Varactors are utilized to realize tunable responses. The bandwidth of the two bands can be controlled individually. Transmission zeros are generated near the passband edges, resulting in high selectivity. For demonstration, a tunable bandpass filter is implemented. Good agreement between the prediction and measurement validates the proposed method.

scholarly journals A Compact Quint-Band Bandpass Filter Based on Stub-Loaded Resonators

2017 ◽  
Vol 7 (3) ◽  
pp. 1694-1698
Author(s):  
M. Farhat ◽  
J. Munisami ◽  
M. Abdul-Niby ◽  
M. Nahas
Keyword(s):  
Design Methodology ◽  
High Selectivity ◽  
Bandpass Filter ◽  
Center Frequency ◽  
High Isolation ◽  
The Third ◽  
Transmission Zeros ◽  
Band Filter ◽  
Sufficient Degree ◽  
Simulation Results

This paper presents a planar quant-band bandpass filter with a high out-of-band rejection. The filter is based on inter-coupled stub-loaded resonators, where pairs of resonators are electromagnetically coupled to each other and the feed lines. This results in excitation of passbands, where the first and the third passbands are generated by λ/4 stub-loaded resonators. The second and the fifth passbands are excited by λ/2 stub-loaded resonators. And the fourth passband is generated by λ/2 resonators. The proposed technique provides sufficient degree of freedom to control the center frequency and bandwidth of the five passbands. In addition, the seven transmission zeros created around the passbands results in a quant-band filter with high selectivity, sharp 3dB cut-off frequency, high isolation, and low passband insertion-loss. Design methodology and simulation results of the filter are provided.

scholarly journals Novel Notched UWB Filter Using Stepped Impedance Stub Loaded Microstrip Resonator and Spurlines

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Ramkumar Uikey ◽  
Ramanand Sagar Sangam ◽  
Kakumanu Prasadu ◽  
Rakhesh Singh Kshetrimayum
Keyword(s):  
Bandpass Filter ◽  
Experimental Results ◽  
Microstrip Resonator ◽  
Resonant Frequencies ◽  
Notched Band ◽  
Band Filter ◽  
5 Ghz ◽  
Good Agreement

This paper presents a novel ultrawideband (UWB) bandpass filter using stepped impedance stub loaded microstrip resonator (SISLMR). The proposed resonator is so formed to allow its four resonant frequencies in the UWB passband, which extends from 3.1 GHz to 10.6 GHz. Moreover, two spurline sections are employed to create a sharp notched-band filter for suppressing the signals of 5 GHz WLAN devices. Experimental results of the fabricated filters are in good agreement with the HFSS simulations and validate the design.

Design of Novel Compact Quad-Band Bandpass Filter with High Selectivity

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 53-59
Author(s):  
Qingchun Cao ◽  
Hui Liu ◽  
Li Gao
Keyword(s):  
Return Loss ◽  
High Selectivity ◽  
Bandpass Filter ◽  
Center Frequency ◽  
Transmission Zeros ◽  
Compact Size ◽  
Left And Right ◽  
Embedded Structure ◽  
Better Than ◽  
Good Agreement

AbstractThis paper presents a compact quad-band bandpass filter. The filter is realized by multi-embedded stub-load resonators. By utilizing multi-embedded structure, the whole filter exhibits a compact size. And due to the multi-section stub-loaded lines, four passbands can be realized and the center frequency of the four passbands can be controlled individually to accommodate different communication protocols. Moreover, by using 0° degree feed structure, there are two transmission zeros locates at left and right side of a passband, which greatly enhance the selectivity. To validate the proposed idea, a quad-band bandpass filter, which operates at 2/2.7/3.45/4.55 GHz is implemented. The insertion loss is smaller than 2 dB and return loss is better than 10 dB. Good agreement between the predicted and measured results demonstrates the proposed idea.

Designing Modern Compact Microstrip Planar Quadband Bandpass Filter for Hand Held Wireless Applications

Frequenz ◽  
2020 ◽  
Vol 74 (5-6) ◽  
pp. 219-227 ◽  
Author(s):  
Abdul Basit ◽  
M. Irfan Khattak
Keyword(s):  
Bandpass Filter ◽  
Mode Analysis ◽  
Dual Mode ◽  
Resonant Frequencies ◽  
Wireless Applications ◽  
The Third ◽  
Transmission Zeros ◽  
Half Wave ◽  
Feeding Structure ◽  
Good Agreement

AbstractThis paper presents a modern compact quad-band bandpass filter (BPF) using dual-mode stub loaded half wave (λ/2) resonators, where a couple of directly fed resonators are loaded with two identical inner resonators such that the direct fed resonators will act as feeding structure for the loaded resonators. Based on the proposed stub loaded resonators, a modern filter with seven transmission zeros (TZs) is designed by folding the two identical inner resonators. The proposed design has a symmetrical geometry, therefore even-odd mode analysis is used to predict the resonant frequencies of the passbands. The first and second passbands are obtained through fundamental odd and even modes respectively while the third one is achieved by placing loaded inner resonators in the proposed design. The second even harmonic of the direct fed resonators is utilized to achieve the fourth passband and is controlled by the stubs loaded at the middle of the resonators. The filter is simulated and fabricated for the purpose of validation, wherein a good agreement can be seen in both simulated and experimental results.

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