Dual-Band Bandpass Filter With Controllable Bandwidths Using Two Coupling Paths
ABSTRACT This letter presents the designs of dual-band bandpass filters using two coupling paths to control the bandwidth of each passband. One coupling path only delivers signals at the upper passband frequency whereas the other one couple signals at both passbands. Utilizing this method, the two bandwidths can be adjusted. The filters make use of stub-loaded resonators and it is convenient to tune the passband frequencies. Therefore, both the frequency and bandwidth of each passband can be easily controlled. For demonstration purpose, two example filters are implemented with different bandwidths. The experimental results are presented to verify the proposed method.
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ABSTRACT: A compact microstrip-line dual-band bandpass filter using a short stub-loaded resonator is presented. The resonator is formed by loading one short stub in shunt to a simple uniform impedance line. A key merit of the filter configuration is that the center frequency and bandwidth of the first passband can be conveniently controlled by properly adjusting the lengths of the short stubs and the coupling between the short stubs, whereas those of the second passband are fixed. To illustrate the concept, a third-order dual-band filter is designed, fabricated and measured. Simulated and measured results are found to be in good agreement with each other.Progress In Electromagnetics Research Letters 01/2012; 32. DOI:10.2528/PIERL12050105
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ABSTRACT: This study reports on tunable planar metamaterial design that is capable to achieve dual-band negative index of refraction responses operating in microwave regime. Its distinctive characteristic is the usage of tuning open stub-loaded stepped-impedance resonators. Parameters retrieval algorithm, and full-wave simulation of prism-shaped structure were carried out to validate the negative refraction characteristics of metamaterial structure. The results predict its prospect as a very promising alternative to the conventional ones, which is compatibly applicable on various potential microwave devices especially when dual-band function is required. In addition to that, its design flexibility offers a various frequency bands at any possible choice, which is alterable together with any design parameters changes.Progress In Electromagnetics Research B 01/2011; 35. DOI:10.2528/PIERB11082209
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ABSTRACT: This paper presents a tri-stubs loaded multimode resonator (TSLMR) for designing dual-band bandpass filters. The TSLMR produces four spitting modes and the modal character is analyzed by using odd- and even-mode methods. A pair of even–odd modes is used to form the first passband, while another pair is used to produce the second passband. This resonator structure provides sufficient degrees of freedom to control the central frequencies and bandwidth of each passbands. Meanwhile, multi-transmission zeros are properly tuned for the rejections between the two passbands and in the upper stopband. A dual-band BPF operating at 1.57 and 3.5 GHz is designed and fabricated. Without a shorted structure and extra resonator, the measured filter shows good performance for both in band matching and outside rejections of the desired dual-passbands.Journal of Electromagnetic Waves and Applications 08/2014; 28(16). DOI:10.1080/09205071.2014.957787 · 1.40 Impact Factor