Compact Wide Stopband Lowpass Filter with High Suppression Using Corrugated Transmission Line

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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Design of Microstrip Lowpass Filter Using bend Configuration with Excellent sharpness in Transition Band

Frequenz ◽

10.1515/freq-2015-0096 ◽

2016 ◽

Vol 70 (5-6) ◽

Cited By ~ 1

Author(s):

Seyed Mohammad Hadi Mousavi ◽

Seyed Vahab Al-Din Makki ◽

Hesam Siahkamari

Keyword(s):

Transmission Line ◽

Lowpass Filter ◽

Transition Band ◽

Rejection Level ◽

Compact Size ◽

Measurement Results ◽

Em Simulation ◽

High Rejection ◽

Very High ◽

Acceptable Agreement

AbstractIn this letter, a microstrip lowpass filter (LPF) using bend configuration with several excellent features such as a compact size, great roll-off rate and high rejection in the stopband is presented. This structure is composed of a spiral transmission line loaded by several stepped impedance and T-shaped resonators. The cut-off frequency of the proposed filter is equal to 2.73 GHz and the transition band is from 2.73 up to 2.82 GHz with –3 and –20 dB attenuation point, respectively, which represents a very high sharpness in the transition band. To achieve a –40 dB rejection level in the stopband, multiple open stub and T-shaped patches are utilized. An acceptable agreement between EM-simulation and measurement results is observed.

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Effect of Current Crowding on Frequency Response of a Stepped Planar RF Transmission-Line Lowpass Filter for Power Electronics

IEEE Transactions on Advanced Packaging ◽

10.1109/tadvp.2006.879413 ◽

2006 ◽

Vol 29 (4) ◽

pp. 798-803 ◽

Cited By ~ 2

Author(s):

Colin Kydd Campbell ◽

Jacobus Daniel van Wyk ◽

Rengang Chen

Keyword(s):

Transmission Line ◽

Frequency Response ◽

Power Electronics ◽

Current Crowding ◽

Lowpass Filter ◽

Rf Transmission

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Design of compact microstrip lowpass filter with ultra-wide stopband using modified T-shaped resonator

International Journal of Microwave and Wireless Technologies ◽

10.1017/s175907871400124x ◽

2014 ◽

Vol 7 (6) ◽

pp. 699-703 ◽

Cited By ~ 4

Author(s):

Behnam Afzali ◽

Mohammad Mehdi Karkhanehchi ◽

Gholamreza Karimi

Keyword(s):

Transmission Line ◽

Equivalent Circuit ◽

Figure Of Merit ◽

Band Width ◽

Exact Equation ◽

Lowpass Filter ◽

Transmission Zero ◽

Compact Size ◽

High Figure ◽

Lc Equivalent Circuit

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 cut-off 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.

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Design of High-Performance Lowpass Filter Using Inter-Coupled Compact Microstrip Resonator Cells

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.487.627 ◽

2012 ◽

Vol 487 ◽

pp. 627-631

Author(s):

Qing Hua Wu ◽

Lin Li

Keyword(s):

Transmission Line ◽

High Performance ◽

Bridge Structure ◽

Lowpass Filter ◽

Microstrip Resonator ◽

Compact Structure ◽

High Impedance ◽

Design Structure ◽

Final Design ◽

In Series

This paper presents a high-performance lowpass filter (LPF) using periodical inter-coupled compact microstrip resonator cells (CMRCs) in series. The CMRC consists of high impedance transmission line and symmetrical T-shaped structure at both sides with ended transmission line arms. By using a bridge structure to introduce controllable inter-coupling between the adjacent tapered CMRC units, the proposed CMRC structure exhibits quasi-elliptic lowpass response with improved stopband performance. Final design of an exemplary LPF using proposed design structure and methodology verify the feasibility of the structure and its high performance including compact structure, low insertion loss, sharp transition and expanded stopband.

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