Quad‐band BPF based on SLRs with inductive source and load coupling

In this paper, a quad-mode dual-band bandpass filter (BPF) only using a stub-loaded circular resonator is presented. The odd-and even-mode resonant frequencies can be easily computed and flexibly controlled by the radius of the circle and the two sets of stubs, as all odd-and even-mode equivalent circuits are half-wavelength resonators (double-ended short-circuited uniform transmission line resonator). Introducing the resonator makes the filter be analyzed and designed easily. To further improve the isolation between the two passbands, a dual-band BPF is designed by introducing the source-load coupling technique; the simulation and test S-parameter curves show that the designed BPF has four controllable transmission zeros. The good agreement of measured data with simulation results verifies the proposed design.

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“…1a. Due to the symmetrical structure of the resonator, the theory of odd and even modes can be used to analyze it [11][12][13].…”

Section: Analysis Of the Proposed Resonatormentioning

confidence: 99%

Quad-mode dual-band bandpass filter based on a stub-loaded circular resonator

Liu

Xiang

Ren

et al. 2019

J Wireless Com Network

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“…As is well known, it is very easy to implement a dual‐band BPF rather than a quad‐band BPF. Therefore, after designing two dual‐band BPFs with different sizes, the two filters used a common input/output . The filter performance is summarized in Table .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, after designing two dual-band BPFs with different sizes, the two filters used a common input/output. [13][14][15][16] The filter performance is summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Simple quad‐band bandpass filter implemented on a 50‐Ω microstrip line

Sung

2019

Micro & Optical Tech Letters

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In this study, we implement a compact quad‐band bandpass filter (BPF) on a 50‐Ω microstrip line. The proposed structure comprises an input/output stage with one end terminated at a 50‐Ω C‐shaped open‐loop resonator. When the gap between the input stage and the output stage is located at the center and the filter structure is symmetric, it acts as a dual‐band BPF, but when the gap moves and the filter structure becomes asymmetric, it acts as a quad‐band BPF. The proposed structure is very small in size because it is implemented on a 50‐Ω line without any additional space. Even though it supports four frequency bands, the design complexity is minimized by reducing the number of design parameters. In addition, analysis of the current distribution and parameter study suggest a method to control only one or two specific resonant frequencies among four resonant frequencies. The fabricated BPF demonstrates four passbands located at 1.5, 3.6, 5.4, and 7.2 GHz. Within the four passbands, the minimum insertion losses are 0.2, 0.6, 1.8, and 1.7 dB, respectively.

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“…The most direct approach is combining several resonators with common input/output ports to achieve a quad-band BPF, which suffers from a relatively large circuit area. For example, in [1], a quad-band BPF is achieved by cascading two dual-band BPFs together with a single metallic via-holed feed line. In [2], a short-end stub-loaded resonator is used to yield the third passband, and the other multi-stub-loaded resonators operate at the first, second, and fourth passband.…”

Section: Introductionmentioning

confidence: 99%

“…To settle these matters, it is vital to introduce TZs on the both sides of each passband. Source-load coupling [1], zero-degree feed lines [3], multi-paths propagation [7], meandering structure [10], and mixed electric and magnetic coupling (MEMC) configuration [11] are all capable to generate additional TZs. Besides, to the author's knowledge, very little research has been reported so far for the quad-band BPF design using QMRs under MEMC.…”

Section: Introductionmentioning

confidence: 99%

A compact quad-band bandpass filter with mixed electric and magnetic coupling

Zhou

Wang

et al. 2019

Int. J. Microw. Wireless Technol.

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In this paper, based on a novel multimode stub-loaded resonator, a second-order quad-band bandpass filter (BPF) with mixed electric and magnetic coupling is presented. The electric coupling and magnetic coupling are realized by arranging the parallel coupled lines and the grounded stub, respectively. Eight controllable resonant modes can be simultaneously excited and easily tuned. Eight transmission zeros are created, enhancing the passband selectivity. In addition, the bandwidths can be controlled independently by adjusting the coupling strength. A quad-band BPF centering at 0.67, 1.51, 2.84, 3.58 GHz with respective 3 dB fractional bandwidths of 13.4, 15.6, 9.2, 11.5% is designed, fabricated, and measured. The filter is compact with overall size 0.058λg × 0.13λg. The measured results show a good consistence with the simulated ones.

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Quad‐band BPF based on SLRs with inductive source and load coupling

Cited by 9 publications

References 10 publications

Quad-mode dual-band bandpass filter based on a stub-loaded circular resonator

Quad-mode dual-band bandpass filter based on a stub-loaded circular resonator

Simple quad‐band bandpass filter implemented on a 50‐Ω microstrip line

A compact quad-band bandpass filter with mixed electric and magnetic coupling

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