Microstrip lowpass filter with wide stopband and sharp roll-off using modified radial stub resonator

A microstrip-based lowpass filter (LPF) containing modified ring structures has been presented. Ring resonators are used to form a sharp transition region. In addition, rectangular- and tapered-shaped suppressing cells are used to create an ultra-wide stopband region. By combining the designed ring resonator and suppressors, an LPF has been designed with −3 dB cut-off frequency at 1.83 GHz. A sharp transition region has been achieved from 1.83 (at −3 dB) to 2.1 GHz (at −60 dB). A stopband region has been concluded from 2 to 21 GHz (with the corresponding attenuation level of at least 20 dB). The measured insertion loss is better than 0.1 dB (equal to a return loss of 18.1 dB) in the passband region. The proposed circuit is fabricated and measured. The measured results have an appropriate adaption with the simulated results.

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“…The important parameters of RL and IL are not included in the FOM equation. Therefore, a new parameter for OFOM is presented below [10]:…”

Section: Design Resultsmentioning

confidence: 99%

“…However, its transition sharpness and insertion loss are not satisfactory. In [10], a radial-shaped LPF has been presented with wide stopband and prefect transition band, but its passband characteristics are not satisfactory. In [11], a large size multi-shaped LPF based on triangle-shaped resonators has been implemented.…”

Section: Introductionmentioning

confidence: 99%

Ultra-wide stopband lowpass filters using ring resonators

Hayati

Mustafa

Shama

et al. 2021

Int. J. Microw. Wireless Technol.

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“…In Table 3, a comparison between the proposed LPF and the other published works is shown, where parameters RSB, SF, ξ (dB/GHz), NCS ( λg ) 2 , AF and FOM correspond to RSB, suppressing factor (SF), roll-off rate, NCS, architecture factor (AF), and FOM, respectively [13].…”

Section: Measurement and Design Resultsmentioning

confidence: 99%

A compact microstrip lowpass filter with wide stopband using rectangular resonator and high impedance elements

Kazemi

Hayati

2019

Int. J. Microw. Wireless Technol.

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In this paper, a microstrip lowpass filter using rectangular resonators is designed. To weaken the undesired harmonics from 10 to 20 GHz, a stair-shaped suppressing cell and also high impedance elements at the edges are utilized. It should be noted that for analyzing the proposed filter, an LC model is used and the design is done in such a way that the coupling effects of the close-up lines are reduced as much as possible, so that they are ignored in the circuit analysis. The designed filter has a cut-off frequency of 1.01 GHz and the transition band is only 0.1 GHz. In addition to compression of dimensions, the stopband bandwidth is 18.7 times the cut-off frequency (18.7 × fc). The attenuation rate in the passband reaches 0.081 dB which indicates that the passband is flat. In the stopband, disturbing harmonics have been dampened to −23.5 dB and a good bandwidth is achieved. The figure of merit of the proposed filter is 180 387 and it is a good benchmark for the overall comparison of the proposed filter with the previous works.

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