scholarly journals A Compact Tri-Band Bandpass Filter with High Out-of-Band Rejection

2017 ◽  
Vol 7 (4) ◽  
pp. 1786-1790
Author(s):  
M. Abdul-Niby ◽  
M. Farhat ◽  
M. Nahas ◽  
Μ. Μ. Alomari

This paper presents a planar tri-band bandpass filter with high out-of-band rejection over a wide band. The filter is based on two pairs of λ/4 resonators embedded inside an open loop ring resonator without any size increase, where each pair of resonators are electromagnetically coupled to each other and the feedlines. This results in the excitations of passbands, where the first passband is generated by the open loop resonators. The second and the third passbands are excited by λ/4 resonators. The proposed technique provides sufficient degrees of freedom to control the center frequency and bandwidth of the three passbands independently. In addition, the six transmission zeros created around the passbands results in a tri-band filter with high selectivity, sharp 3 dB cut-off frequency, high isolation, low passband insertion-loss and high out-of-band harmonic rejection across an ultra-broadband frequency range up to 17 GHz. The proposed technique has the ability to switch from triple to dual band by removing one pair of the inner resonators. Design methodology and simulation results of the filter are provided.

Frequenz ◽  
2016 ◽  
Vol 70 (9-10) ◽  
Author(s):  
Chuanming Zhu ◽  
Jin Xu ◽  
Wei Kang ◽  
Zhenxin Hu ◽  
Wen Wu

AbstractIn this paper, a miniaturized dual-band bandpass filter (DB-BPF) using embedded dual-mode resonator (DMR) with controllable bandwidths is proposed. Two passbands are generated by two sets of resonators operating at two different frequencies. One set of resonators is utilized not only as the resonant elements that yield the lower passband, but also as the feeding structures with source-load coupling to excite the other to produce the upper passband. Sufficient degrees of freedom are achieved to control the center frequencies and bandwidths of two passbands. Moreover, multiple transmission zeros (TZs) are created to improve the passband selectivity of the filter. The design of the filter has been demonstrated by the measurement. The filter features not only miniaturized circuit sizes, low insertion loss, independently controllable central frequencies, but also controllable bandwidths and TZs.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sheng Zhang ◽  
Chao Ji ◽  
Meng-Han Tong ◽  
Zhen-Jiang Xie ◽  
Cong Xu

Abstract A compact dual-band balanced bandpass filter with high frequency selectivity and adjustable passband based on the perturbed circular substrate integrated waveguide cavity is firstly proposed in this paper. Two pairs of metallic vias are located at 45°direction of cavities to separate a pair of degenerate modes (TM110 modes) to achieve the differential-mode (DM) dual-band response. Moreover, the perturbation vias can also be used to control the center frequency of the second DM passband while the first one still stays unaffected. The introduction of source-load coupling makes the filter exhibit excellent selectivity. And four controllable transmission zeros appear near two DM passbands. Finally, good common-mode suppression has been got owing to the proposed balanced structure. The measured results are in accordance with the simulated ones well.


2018 ◽  
Vol 27 (07) ◽  
pp. 1850100 ◽  
Author(s):  
Amit Bage ◽  
Sushrut Das

This paper presents a planar insert-loaded compact, dual-pole, dual-band, waveguide bandpass filter with adjustable multiple transmission zeros. Two identical inserts are placed on the transverse plane of a standard WR-90 waveguide at 8.41[Formula: see text]mm distance to achieve the filter characteristics. The insert consists of a stub-loaded C-shaped resonator and two asymmetric slot resonators. Two stub-loaded C-shaped resonators have been used to achieve dual-pole, dual-band response whereas the asymmetric slot pairs have been used to introduce transmission zeros. The structure allows independent control of the center frequencies of the passbands and transmission zeros, which is useful to control the rejection level of out-of-band signals without disturbing the center frequency. Measured result shows a dual-pole, dual-band, bandpass response with center frequencies at 8.81[Formula: see text]GHz and 10.9[Formula: see text]GHz, the respective 3[Formula: see text]dB bandwidths of 0.276[Formula: see text]GHz and 0.398[Formula: see text]GHz and transmission zeros at 8.02, 8.5, 9.46, 10.13, 11.53 and 12 GHz.


2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Chia-Mao Chen ◽  
Shoou-Jinn Chang ◽  
Yen-Liang Pan ◽  
Cheng-Yi Chen ◽  
Cheng-Fu Yang

A new type of balun-bandpass filter was proposed based on the traditional coupled-line theory and folded open-loop ring resonators (OLRRs) configuration. For that, a new device with both filter-type and balun-type characteristics was investigated and fabricated. Both magnetic and electric coupling structures were implemented to provide high performance balun-bandpass responses. The fabricated balun-bandpass filters had a wide bandwidth more than 200 MHz and a low insertion loss less than 2.51 dB at a center frequency of 2.6 GHz. The differences between the two outputs were below 0.4 dB in magnitude and within 180 ± 7° in phase. Also, the balun-bandpass filter presented an excellent common-mode rejection ratio over 25 dB in the passband. An advanced design methodology had been adopted based on EM simulation for making these designed parameters of OLRRs, microstrip lines, and open stubs. The measured frequency responses agreed well with simulated ones.


2017 ◽  
Vol 7 (3) ◽  
pp. 1694-1698
Author(s):  
M. Farhat ◽  
J. Munisami ◽  
M. Abdul-Niby ◽  
M. Nahas

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.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Liyun Shi ◽  
Jianjun Gao

A planer millimetre-wave dual-band bandpass filter with multitransmission zeros is proposed for 5G application. This filter includes two dual-mode open-loop resonators. The U-shape nonresonating node is employed to generate an extra coupling path. Finally, a dual-band bandpass filter with five transmission zeros is obtained. The filter is fabricated and measured. Good agreement between simulation and measurement is obtained.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chia-Mao Chen ◽  
Shoou-Jinn Chang ◽  
Sung-Mao Wu ◽  
Yuan-Tai Hsieh ◽  
Cheng-Fu Yang

A balun-bandpass filter was proposed by using two folded open-loop ring resonators (OLRRs) to couple three microstrip lines. By tuning the size of the OLRR, the operating frequency of the balun-bandpass filter could be tuned to the needed value. By tuning the size of open stub at the end of microstrip lines, the balanced impedance of the balun-bandpass filter could also be tuned. The fabricated balun-bandpass filter had a wide bandwidth and a low insertion loss at center frequency of the passband. The balun-bandpass filter presented an excellent in-band balanced performance with common-mode rejection ratio more than 20 dB in the passbands. An advanced design methodology had been adopted based on EM simulation for making these designed parameters of OLRRs and microstrip lines. Good correlation was seen between simulation and measurement, and the result was that first run pass had been achieved in the majority of our designs.


2020 ◽  
Vol 9 (1) ◽  
pp. 65-69
Author(s):  
H. A. Atallah

This work proposes a design of compact filter-antenna with fixed and frequency-agile bands for wireless communications and cognitive radio (CR) systems. The filter-antenna is realized by attaching a bandpass filter with an independent fixed band and a tunable band to a UWB antenna. The dual bandpass filter consists of a folded open loop resonator loaded with single varactor diode at a suitable location to achieve reconfigurability operations for the high band while the low band remains fixed at 4.5 GHz. A reconfigurable broadband frequency range of 3.2 GHz from 7.8 to 4.6 GHz is achieved for the high band by changing the capacitance of the varactor from 0.16 to 2.25 pF, respectively. A prototype of the filter-antenna is fabricated and measured at a selected capacitance of 0.6 pF to verify the simulation results. Good agreements between simulated and measured results are obtained.


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