A New Approach to Design and Analysis of a Novel Ultra Wide-Stopband Low Pass Filter Using a Modified U-Shaped Resonator (original) (raw)
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Compact low‐pass filter with ultra‐wide stopband using analysed triangular‐shaped resonator
Electronics Letters, 2017
Background and Objectives: In this paper, an ultra-wide stopband microstrip low pass filter (LPF) with sharp roll-off and compact size is designed and fabricated. Also, proposed filter is designed, simulated, optimized, fabricated and measured and we can see a good agreement between the simulations and measurement results. Methods: T-shaped and stepped impedance have been used, because these structures have a very small dimensions. This method provides a suitable cut off frequency. Results: The cut off frequency at-3dB is 3.1GHz. In the proposed structure, the insertion loss is lower than 0.12dB and the return loss is greater than 15dB. In order to achieve a-20dB attenuation level in the stopband, a modified L-shaped structure is utilized. This filter has an ultra-wide stopband that is expanded from 3.37GHz to 37.5GHz. Also, the suppression level is greater than-20dB. The fabricated LPF has a size about 16.6 × 13.5 mm 2 which is equal to 0.28ƛg × 0.22ƛg, where ƛg is the guided wavelength at 3.1GHz, which is very small. Conclusion: A microstrip LPF with 3.1GHz cutoff frequency consisting of Tshaped and stepped impedance resonators has been proposed, simulated and fabricated. The transition band (-3 to-40dB) is 0.38GHz, which is a very sharp response. The stopband of the proposed filter is from 3.37 to 37.5 GHz which is equal to 12.1f c. There was a significant agreement between the simulation and the measured results. With all these features, these filters are widely used in wireless communication systems.
Design of Microstrip Low-Pass Filter with Ultra-wide Stopband and Sharp Rejection
In this paper, a microstrip lowpass filter with ultra-wide stopband and sharp rejection is presented. To achieve sharp frequency response and ultra-wide stopband, both closed loop stepped impedance (CLSI) and U-shape resonators are used. Accordingly the proposed filter with 3 dB Cutoff frequency at 3.63 GHz has been designed, fabricated and measured. The rejection band extended over-20dB from 3.95GHz to 40GHz. This stopband bandwidth is equal to 9.93 fc, moreover the size of the filter is 0.33λg×0.18 λg, which was: λg is the guided wavelength at the Cutoff frequency. The filter design based on scale factor of its component has been investigated to generalize its characteristics to the other practical Cutoff frequency. It was concluded that the measurement results are in good agreement with simulations.
Microstrip lowpass filter with ultra-wide stopband using triangular shaped CMRC
International Journal of Electronics, 2014
In this article, a new microstrip lowpass filter with ultra-wide stopband using T-shaped resonators and folded structures is described. The structure of this filter is very simple, so that only a T-shaped resonator is used as main resonator without any particular changes in these resonators. The designed T-shaped main resonator has a −3 dB cutoff frequency of 1.4 GHz. On the other hand, T-shaped resonators with low base length are utilized as suppressing cells. To provide an ultra-wide stopband, two pair of T-shaped resonator and two high frequency suppressing cells are employed. The structure of this filter is folded to have compact size. The measured results shows −3 dB cutoff frequency of 1.4 GHz. The transition band is equal to 0.25 GHz from 1.4 to 1.65 GHz, with corresponding attenuation levels of −3 to −20 dB. The ultra-wide stopband with −22 dB suppression level is from 1.68 to 40 GHz. Also, the total size of the proposed lowpass filter is 16.8 × 11.3 mm 2 .
Design of compact microstrip lowpass filter with ultra-wide stopband
Electronics Letters, 2012
behnam afzali 1 , mohammad mehdi karkhanehchi 2 and gholamreza karimi 2 A new microstrip lowpass filter with compact size and ultra-wide stopband using T-shaped resonator is proposed. To make smaller the circuit size of the filter, cursive transmission line is also suggested. Moreover, exact equation of most important transmission zero is calculated based on LC equivalent circuit and transformation function. A demonstration filter with 3 dB cutoff frequency at 1.02 has been designed, fabricated, and measured. Results show that a relative stopband band width of 166.3% (referred to suppression degree of 20 dB) is achieved while obtaining high figure of merit of 46 274.
A Compact Lowpass Filter with Ultra Wide Stopband using Stepped Impedance Resonator
Radioengineering, 2017
In this paper, a compact asymmetric-shaped microstrip lowpass filter (LPF) using a stepped impedance resonator is presented. An ultra wide stopband with high attenuation in the stopband region, within very small circuit area is achieved for the proposed filter using novel asymmetric structures for resonator and suppressor. The transmission zeros of the resonators can be adjusted as a function of high impedance and low impedance microstrip lines, and due to the asymmetric structure, the proposed suppressing cell can be located within the resonator structure without occupying a large area. For verification, a 2.92 GHz LPF is designed and fabricated. The experimental results, in comparison with the other LPFs, show that the proposed LPF has significant advantages in the stopband characteristics with acceptable sharp roll off. The measured passband insertion loss is below 0.1 dB, and the rejection band over-20 dB is obtained from 3.42 GHz to 36.2 GHz. The size of filter corresponds to compact electrical size of 0.156 λ g × 0.128 λ g , where λ g is the guided wavelength at 2.92 GHz. Also, the maximum variation of the group delay in 80 percent of the passband region is only about 0.2 ns.
Compact Low Pass Filter Using Sharp Roll-off Ultra-Wide Stopband T-shaped Resonator
2018
Background and Objectives: In this paper, an ultra-wide stopband microstrip low pass filter (LPF) with sharp roll-off and compact size is designed and fabricated. Also, proposed filter is designed, simulated, optimized, fabricated and measured and we can see a good agreement between the simulations and measurement results. Methods: T-shaped and stepped impedance have been used, because these structures have a very small dimensions. This method provides a suitable cut off frequency. Results: The cut off frequency at -3dB is 3.1GHz. In the proposed structure, the insertion loss is lower than 0.12dB and the return loss is greater than 15dB. In order to achieve a -20dB attenuation level in the stopband, a modified L-shaped structure is utilized. This filter has an ultra-wide stopband that is expanded from 3.37GHz to 37.5GHz. Also, the suppression level is greater than -20dB. The fabricated LPF has a size about 16.6 × 13.5 mm2 which is equal to 0.28ƛg × 0.22ƛg, where ƛg is the guided wa...
Microstrip Lowpass Filter with Ultrawide Stopband and Sharp Roll-off
Arabian journal for science and engineering, 2014
In this article, a new microstrip lowpass filter with ultra-wide stopband using T-shaped resonators and folded structures is described. The structure of this filter is very simple, so that only a T-shaped resonator is used as main resonator without any particular changes in these resonators. The designed T-shaped main resonator has a −3 dB cutoff frequency of 1.4 GHz. On the other hand, T-shaped resonators with low base length are utilized as suppressing cells. To provide an ultra-wide stopband, two pair of T-shaped resonator and two high frequency suppressing cells are employed. The structure of this filter is folded to have compact size. The measured results shows −3 dB cutoff frequency of 1.4 GHz. The transition band is equal to 0.25 GHz from 1.4 to 1.65 GHz, with corresponding attenuation levels of −3 to −20 dB. The ultra-wide stopband with −22 dB suppression level is from 1.68 to 40 GHz. Also, the total size of the proposed lowpass filter is 16.8 × 11.3 mm 2 .
Sharp Roll-Off Ultra Wide Stopband Compact Microstrip Lowpass Filter Using Square-Shaped Resonator
Majlesi Journal of Electrical Engineering, 2019
In this paper, a novel compact microstrip Low-Pass Filter (LPF) with sharp roll-off and ultra-wide stopband with high suppression level is presented. In the proposed filter, square-shaped resonators are used. The cut-off frequency at 3dB is 1.88GHz. The maximum insertion loss of this filter is less than 0.1dB and the return loss is also less than 16dB in the passband. In the proposed structure, the stopband extends from 2.07 to 29.5 GHz at 24dB level of suppression and is considered as an ultra-wide stopband. There is a significant relationship between simulation and fabrication results, which have justified the functionality of the proposed LFP, respectively.
Compact Microstrip Low-Pass Filter with wide stopband using symmetrical U-shaped resonator
2012
This paper peresents a novel Microstrip Low-Pass Filter (LPF) using a simple symmetrical U-shaped resonator. In this work, a 5.45 GHz LPF is developed. The experimental results show that in comparison with other LPFs, it has a wide stopband with high attenuation in the stopband and acceptable sharp frequency response. The insertion-loss is less than 0.1 dB and the rejection band over −20 dB covers 6.05 GHz to 37.35 GHz. The measured and simulated results are in good agreement.
An ultrawide stopband lowpass filter is reported using three stepped impedance resonators with high selectivity. The filter extends the stopband frequency range and attenuation, and two quarter-wave open stubs and three circular ground slots are introduced. The lumped and distributed equivalent models are derived and analyzed. The corresponding results are validated experimentally in a fabricated prototype. The prototype lowpass filter has a 3 dB cutoff frequency (f c) of 2.9 GHz, and the stopband is extended up to 35 GHz (12.07f c), with an attenuation level better than 20 dB throughout. The passband-to-stopband transition (3 dB-20 dB) bandwidth is 0.18 GHz, and the roll-off factor is 135 dB/GHz at 30 dB. The insertion loss is 0.3 dB at 1.6 GHz. The normalized circuit size of the proposed filter with respect to the guided wavelength is 0.04.