scholarly journals A compact simple microstrip lowpass filter based on elliptical analyzed resonator

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohsen Hayati ◽  
Saeedeh Lotfi ◽  
Hesam Siahkamari ◽  
Tomas Blecha ◽  
Richard Linhart ◽  
...  
Keyword(s):  
Lowpass Filter ◽  
Transmission Zeros ◽  
Input Ratio

Abstract In this article, a compact microstrip lowpass filter (LPF) using elliptical shaped resonators with ultra-wide stopband is rendered. In this respect, LC equal structures of the elliptical shaped resonators are calculated based on the formula of circumference. In addition, to calculate transmission zeros of the presented elliptical shaped resonator, the LC equal structure and its output to input ratio are employed. The proposed LPF has a −3 dB cut-off frequency at 1.50 GHz and the stopband bandwidth of the designed filter is about 13fc, which refers to its ultra-wide stopband. The occupied circuit size of the presented filter is 0.151λ g  × 0.044λ g (λ g is the guided wavelength at 1.50 GHz). The designed filter is fabricated on RT/Duroid 5880 substrate. The results of the fabricated and designed filter have clearly demonstrated that not only has the proposed LPF shown a suitable agreement between measured and simulated S-parameters, but also an appropriate stopband bandwidth.

A novel compact lowpass filter with sharp roll-off and wide stopband

2019 ◽  
Vol 12 (1) ◽  
pp. 21-33
Author(s):  
M. Hayati ◽  
AS. Abdipour ◽  
AR. Abdipour
Keyword(s):  
Transmission Lines ◽  
Lowpass Filter ◽  
Transmission Zeros ◽  
High Impedance ◽  
Attenuation Level ◽  
Measurement Results ◽  
High Figure ◽  
Frequency Behavior ◽  
Better Than ◽  
Resonance Cell

AbstractIn this paper, a microstrip lowpass filter adopting two main resonators with steep transition band and wide rejection band has been introduced. The first main resonance cell consists of meandered transmission lines which are loaded by modified T-shaped patches. The second main resonator is composed of high-impedance lines loaded by polygon patches. To obtain a steep skirt performance, the first and second resonators have been combined. Moreover, employing eight high–low impedance folded stubs and two rectangular open-stubs as suppressing cells has resulted in improving the stopband features. To comprehend the frequency behavior of the employed resonators and also their combination, the formulas of the transmission coefficient, reflection coefficient, and the transmission zeros of their equivalent LC circuits have been extracted, separately. According to the measurement results, the −3 dB operating frequency of this filter is 1.65 GHz. Moreover, a relative stopband bandwidth equal to 166% with a corresponding attenuation level of 23 dB and a sharp roll-off rate (393.61 dB/GHz) have been achieved. In the passband region from DC to 1.632 GHz, the insertion loss and return loss are better than 0.0763 and 15.85 dB, respectively, proving an acceptable in-band performance. Finally, the implemented structure brings about a high figure-of-merit equal to 81 672.

scholarly journals Dual-Band Bandpass Filter With Controllable Stopband Bandwidth

2022 ◽  
Vol 9 ◽  
Author(s):  
Nan Wang ◽  
Haokun Wei ◽  
Kun Gao ◽  
Xiting Ruan ◽  
Xiaojian Chen ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Bandpass Filter ◽  
Dual Band ◽  
Lowpass Filter ◽  
Microstrip Filter ◽  
Design Specifications ◽  
Transmission Zeros ◽  
Good Agreement

A novel dual-band bandpass filter (BPF) is proposed with independently controllable transmission zeros (TZs) which can realize widely tunable stopband bandwidth (BW). The planar microstrip filter consists of a three-degree L-C ladder lowpass filter loaded with two unsymmetrical shorted stubs which are used to produce different TZs. By tuning the parameters of the two unsymmetrical shorted stubs, the TZs can be independently controlled. Therefore, the BPF has independent controllable center frequencies (CFs), passband bandwidths, and stopband bandwidths between adjacent passbands. All the L-C values in the equivalent circuit of the proposed filter are optimized to fulfill the design specifications. For demonstration, a dual-band BPF is designed. The measured results show good agreement with the simulated ones.

A Compact Lowpass Filter with Four Transmission Zeros Using Single-Sided Compact Microstrip Resonator Cells

2012 ◽  
Vol 487 ◽  
pp. 125-129
Author(s):  
Kai Yu Zhao ◽  
Lin Li
Keyword(s):  
Insertion Loss ◽  
Return Loss ◽  
Cutoff Frequency ◽  
Lowpass Filter ◽  
Sharp Transition ◽  
Microstrip Resonator ◽  
Broad Bandwidth ◽  
Transmission Zeros ◽  
Compact Size ◽  
Low Insertion Loss

A compact lowpass filter using two single-sided compact microstrip resonator cells （CMRCs）with low insertion loss and broad bandwidth is presented. The cutoff frequency is about 1.4 GHz, the insertion loss is less than 0.6 dB and the 20dB bandwidth is up to the range from 2.1 GHz to 9.8 GHz by means of introducing four transmission zeros through two CMRCs. In addition, the simulated results demonstrate that the proposed filter is characterized by a compact size, low insertion loss, sharp transition, low return loss and wide bandwidth.

scholarly journals Half-Elliptical Resonator Lowpass Filter with a Wide Stopband for Low Band 5G Communication Systems

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2916
Author(s):  
Rasoul Azadi ◽  
Saeed Roshani ◽  
Arez Nosratpour ◽  
Ali Lalbakhsh ◽  
Mohammad Hazhir Mozaffari
Keyword(s):  
Transfer Function ◽  
Loss Tangent ◽  
Communication Systems ◽  
Figure Of Merit ◽  
State Of The Art ◽  
The State ◽  
Lowpass Filter ◽  
Transmission Zero ◽  
Transmission Zeros ◽  
Good Agreement

In this paper, a lowpass filter is designed using half elliptical resonators with a wide stopband. New formulas are presented to achieve a circuit model for the half elliptical resonators used in this work. Additionally, the transfer function and transmission zero equations are used to adjust the frequency of the transmission zeros of the filter. The cut-off frequency of the lowpass filter is 1.26 GHz with a sufficiently large stopband, extending from 1.48 GHz to 20 GHz. The proposed filter’s figure of merit is 62,520, demonstrating its outperformance compared to the state of the art. The filter is implemented on a RT-5880 substrate with a constant dielectric of 2.2, thickness of 31 mil and loss tangent of 0.0009. The LPF was fabricated and tested, showing good agreement between the simulated and measured results.

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