Circuit Modeling and EM Simulation Verification of DGS based Low-Pass Filter Employing Transmission Line Model along with Microstrip-Slotline Transitions

Abstract A microstrip planar lowpass filter with ultra-wide stopband up to 40 GHz is presented. The filter is designed based on four types of hexagonal-shaped resonators, producing multiple transmission zeroes and extending the stopband. The high-impedance transmission line is folded to make the circuit more compact and form the coupling gaps between the adjacent resonators. A pair of folded open stubs are added to enhance the cut-off rate. As a result, an ultra-wide stopband with 23rd-harmonic suppression has been attained. A demonstration filter has been designed and fabricated with 3 dB cut-off frequency of 1.70 GHz. The measured results show that the relative stop bandwidth of the low-pass filter (LPF) is 182% with suppression level of 25 dB, covering 1.85–40 GHz. The functional area size of the filter is 21.50 × 21.70 mm, which corresponds to 0.198λ g × 0.200λ g (λ g is the guided wavelength at 3 dB cut-off frequency).

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Fractional low-pass electrical transmission line model: Dynamic behaviors of exact solutions with the impact of fractionality and free parameters

Results in Physics ◽

10.1016/j.rinp.2021.104457 ◽

2021 ◽

pp. 104457

Author(s):

Md. Nuruzzaman ◽

Dipankar Kumar ◽

Gour Chandra Paul

Keyword(s):

Transmission Line ◽

Exact Solutions ◽

Transmission Line Model ◽

Electrical Transmission ◽

Line Model ◽

Dynamic Behaviors ◽

Electrical Transmission Line ◽

Low Pass ◽

Free Parameters ◽

The Impact

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A compact microstrip low-pass filter with ultra wide stopband using compact microstrip resonant cells

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078716001161 ◽

2016 ◽

Vol 9 (5) ◽

pp. 1023-1027 ◽

Cited By ~ 9

Author(s):

Saeed Roshani

Keyword(s):

Transmission Line ◽

Insertion Loss ◽

Stop Band ◽

Pass Filter ◽

Low Pass Filter ◽

High Impedance ◽

Attenuation Level ◽

Low Pass ◽

High Rejection ◽

Good Agreement

In this paper, a novel compact microstrip low-pass filter (LPF) with ultra wide stop band and sharp roll off, is proposed. In the proposed structure, a high impedance transmission line is loaded by compact microstrip resonant cells, which results in ultra wide stopband. The −3 dB cut-off frequency of filter is 1.5 GHz and the maximum insertion loss is <0.1 dB in the passband. The proposed LPF presents extremely wide stopband from 1.68 to 44 GHz, with more than the −20 dB attenuation level, which suppresses the 2nd to 29th harmonics with high rejection levels. The size of the proposed LPF is only 0.1 λg × 0.19 λg, which shows excellent size reduction. There is a good agreement between the simulated and measured results.

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Stopband-Extended and Size-Miniaturized Low-Pass Filter Based on Interdigital Capacitor Loaded Hairpin Resonator with Four Transmission Zeros

Frequenz ◽

10.1515/freq-2017-0062 ◽

2018 ◽

Vol 72 (5-6) ◽

pp. 221-226 ◽

Cited By ~ 2

Author(s):

Jia-Jia Wu ◽

Lin Li

Keyword(s):

Transmission Line ◽

Pass Filter ◽

Low Pass Filter ◽

Interdigital Capacitor ◽

Transmission Zeros ◽

High Impedance ◽

Compact Size ◽

Low Pass ◽

Hairpin Resonator

AbstractIn this paper, a compact low-pass filter (LPF) with wide stopband is proposed based on interdigital capacitor loaded hairpin resonator. The structure composed of an upper high-impedance transmission line, a middle interdigital capacitor, and a pair of inter-coupled symmetrical stepped-impedance stubs. Detailed investigation into this structure based on even-odd mode approach reveals that up to four transmission zeros can be generated and reallocated by choosing the proper circuit parameters. And owing to the aid of transmission zeros, the fabricated quasi-elliptic LPFs experimentally demonstrate a wide 20dB stopband from 1.4fcto 5.1fcusing a compact size of only 0.005 λg2.

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