scholarly journals Inter-connected coupled lines Resonator topology for bandpass filter application

Author(s):  
Mohd Nasiruddin Hushim ◽  
Norfishah Ab Wahab ◽  
Tn. Syarifah Atifah Tn. Mat Zin ◽  
Norlia Ghazali

This paper presents an inter-connected side-shorted coupled-line resonator topology as a base cell. The base cell is built from two single-shorted quarter-wavelength coupled-line sections, connected in series to give a half-wavelength coupled-line that creates a single resonance of bandpass filter response. Higher-order bandpass filter is produced by adding new single-shorted coupled-line sections, cascaded in an inter-connected manner to the base cell. This new topology creates a unique arrangement that caused cross coupling effects between the resonators, resulting to the occurrence of transmission zeros that lead to the improvement of selectivity of the higher order bandpass filter response. For validation of concept, 2<sup>nd</sup> and 3<sup>rd</sup> order bandpass filters were fabricated using microstrip technology on Roger 3210 substrate with parameter of <em>Ɛr</em> = 10.2, <em>h</em> = 1.27 mm and <em>tan δ</em> = 3x10-3. The filters were measured and the results show good agreement with simulation results.

Author(s):  
Mohd Nasiruddin Hushim ◽  
Norfishah Ab Wahab ◽  
Muhammad Farid Abdul Khalid ◽  
Tn. Syarifah Atifah Tn. Mat Zin

This paper presents an implementation of quarter wavelength single-shorted coupled-lines for narrow bandpass filter application. It is shown as a new way of creating a single resonance bandpass filter by inter-connected of two <br /> single-shorted quarter wavelength coupled-line sections. By adding more single-shorted coupled-line into the configuration, the form of halfwavelength resonator can increase the degree of order of the filter. For the design of 4<sup>th</sup> order resonator, the coupledlines are arranged inter-connected to each other forming five-fingers lines layout. Due to the interconnection of the coupledlines, transmission zeros appear at the two stopbands which improves the selectivity of the filter response. Investigation on the parametric of the 4<sup>th</sup> order resonator is conducted to observe the controlling parameters and it’s realiability responses of the resonator. For compactness, five-fingers meandered lines is proposed. It is found that the size of the meandered lines resonator was successfully reduced by 33% compared to the five-fingers straight lines resonator of the same order. For validation of concept, the 4<sup>th</sup> order meandered lines resonator was designed at 1 GHz and fabricated on RO3210 microstrip substrate with characteristics given as h = 1.27 mm, Ɛr = 10.2 and tan δ = 3x10<sup>-3</sup>. The measurement results show good agreement with the simulation results.


2015 ◽  
Vol 8 (8) ◽  
pp. 1183-1186 ◽  
Author(s):  
S. Almorqi ◽  
H. Shaman ◽  
A. Alamoudi

A multilayer bandpass filter with ultra-wideband passband is presented in this paper. The filter is designed to have a very wide passband with a fractional bandwidth of about 180% at a center frequency of 10.5 GHz. The filter consists of two sections of parallel-coupled lines loaded at the center with short-circuited stub. Each of the coupled line sections and short-circuited stubs is designed to be a quarter-wavelength long at the desired center frequency. As a result, the filter exhibited a selective filtering characteristic equivalent to a five-pole Chebyshev filter with a very low insertion loss. The proposed filter is realized and fabricated using multilayer liquid crystal polymer substrate. The design is successfully realized in theory and verified by full-wave electromagnetic simulation of the full layout and the experiment where excellent agreement is obtained.


2013 ◽  
Vol 655-657 ◽  
pp. 1555-1561
Author(s):  
Wen Ko ◽  
Man Long Her ◽  
Ming Wei Hsu ◽  
Yu Lin Wang

This study proposes a circuit structure with reconfigurable multiple bands bandpass filter. This circuit can provide a triple-band or dual-band bandpass facility by adjusting two open stubs (L6 and L7) location. The circuit design used three sections of transmission line in series, the two sets of the coupled lines connected to the gap in each transmission line, and two open stubs in the appropriate locations. The design and manufacturing of the circuit structure is innovative and simple. The center frequencies of the triple-band bandpass filter are set at 2.4, 4.2, and 6.5 GHz, respectively, while the center frequencies of the dual-band bandpass filter are the two lower pass band of the triple-band bandpass filter at 2.4 and 4.2GHz. The filters were simulated using the full-wave electromagnetic simulator, IE3D, and measured by Anritsu-37269D. The simulated and measured results show good agreement in the frequency of interest.


2020 ◽  
Vol 10 (19) ◽  
pp. 6807
Author(s):  
Jie Cui ◽  
Haojie Chang ◽  
Renli Zhang

A multilayer bandpass filter with high selectivity is proposed in this letter. Discriminating coupling formed by slot-coupled quarter-wavelength and half-wavelength resonators introduces a zero at 3f0 (f0 is the center frequency) and the second harmonic is also suppressed due to the quarter-wavelength resonators. Owing to multilayer structure, source-load coupling is introduced to improve selectivity. Then an extra coupled line path is added with the same amplitude as the discriminating coupling path while they are out of phase. Thus signal cancellation produces three extra transmission zeros, with the selectivity and suppression performance further improved. To validate the design, a prototype bandpass filter centered at 2.49 GHz with 3 dB fractional bandwidth of 8.1% is fabricated. Both simulated and measured results are in good agreement and show good performance of the proposed bandpass filter.


Author(s):  
Norfishah Ab Wahab ◽  
M. N. Md Tan ◽  
M. N. Hushim

<p class="Pa41">This paper presents a single mode pseudo-elliptic bandpass resonator based on closed-loop ring topology. The resonator is built from six quarter wavelength transmission lines to form a square closed-loop ring structure. This structure creates transmission zeros at the lower and upper sidebands so that high selectivity bandpass filter response is achieved. The advantage of this topology is that the design is less complex since no perturbation is needed on the ring lines for creation of transmission zeros. Higher-order filters can be constructed by introducing quarter-wavelength coupled-lines, coupled at both input and output of the closed-loop ring resonator. For proof of concept, the filters are designed at 10 GHz up to 3<sup>rd</sup> order, simulated using full-wave electromagnetic simulator on microstrip substrate, <em>FR-4</em> with characteristics given as <em>Ԑr </em>= 4.70, <em>h </em>= 1.499 mm and <em>tan δ </em>= 0.012.  The filters are simulated and responses are found to be agreeable with the proposed idea.</p>


2020 ◽  
Author(s):  
Xiaohu Wu ◽  
Xiaoguang Liu ◽  
Yingsong Li

In this article, we present the first demonstration of distributed and symmetrical all-band quasi-absorptive filters that can be designed to arbitrarily high orders. The proposed quasi-absorptive filter consists of a bandpass section (reflective-type coupled-line filter) and absorptive sections (a matched resistor in series with a shorted quarter-wavelength transmission line). Through a detailed analysis, we show that the absorptive sections not only eliminate out-of-band reflections but also determine the passband bandwidth (BW). As such, the bandpass section mainly determines the out-of-band roll-off and the order of the filter can be arbitrarily increased without affecting the filter BW by cascading more bandpass sections. A set of 2.45-GHz one-, two-, and three-pole quasi-absorptive microstrip bandpass filters are designed and measured. The filters show simultaneous input and output absorption across both the passband and the stopband. Measurement results agree very well with the simulation and validate the proposed design concept.


2020 ◽  
Vol 35 (9) ◽  
pp. 1053-1058
Author(s):  
Pratik Mondal ◽  
Susanta Parui ◽  
Rajesh Bera

In this paper, a conductor backed coplanar waveguide (CB-CPW) 3rd order bandpass filter is designed using coupled open-ended stub resonator placed vertically to the signal line. Vertically loaded open ended stubs are designed at quarter wavelength so as to behave like a short circuit at the input terminal thus giving a band-accepted response with lesser metallic area or minimum size. Four such coupled open ended resonators are placed in series and also in closely manner to provide greater field confinement of the proposed bandpass filter. The bandpass filter is designed for a center frequency of 2.5 GHz with FBW of 97.89%, insertion loss of <0.5dB, rising and falling edge selectivity of 30.75 dB/GHz and 27.01dB/GHz respectively with a wide stopband of around 4GHz after the desired passband. Further to validate the design technique six such resonators are placed to obtain 5th order bandpass filter.


Frequenz ◽  
2017 ◽  
Vol 71 (7-8) ◽  
Author(s):  
Xuedao Wang ◽  
Jianpeng Wang ◽  
Gang Zhang ◽  
Feng Huang

AbstractA new microstrip coupled-line balun topology and its application to the balun bandpass filter (BPF) with a triple mode response are proposed in this paper. The involved balun structure is composed of two back-to-back quarter-wavelength (


2021 ◽  
Vol 3 (1) ◽  
pp. 44-52
Author(s):  
Mubina Sasic ◽  
Sehabbedin Taha Imeci

This project contains basic information, design, 3D projection, simulation, and analysis of Microstrip Bandpass Filter. The filter was composed of the feed lines connected to the two ports with the parallel coupled lines between them. The separation between these elements is reduced to the minimum for the purpose of reducing the error. Ultimately, the microstrip bandpass filter was designed with a 400 MHz bandwidth. We end up with these result: at the 4.43 GHz, S11 parameter is -9.868 dB and S22 is -1.808 dB, while at the 4.83 GHz, S11 is -9.995 dB and S22 is -1.826 dB.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Abbas Mohamadinia ◽  
Farzin Shama ◽  
Mohammad Amir Sattari

Abstract In this paper, a bandpass filter (BPF) has been designed using bent and coupled-line structure. The design process of the filter to achieve a BPF with good characteristics is completely explained. Therefore the LC equivalent circuit of The BPF is presented as the analytical description. The proposed filter can pass frequencies between 2.2 and 3.6 GHz with an insertion loss <0.4 dB, which is suitable for wireless applications. The fractional bandwidths (FBW) of the filter is about 48%. Some characteristics such as small size, low insertion loss, high return loss wide upper stopband bandwidth, and good suppression level in stopband are among the advantages of this study to be mentioned. Finally, the presented filter was fabricated, and the measured results have a proper agreement with the simulation results.


Sign in / Sign up

Export Citation Format

Share Document