Pseudo-elliptic narrow bandpass filter  using shorted coupled-line of higher order design

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 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 4th 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 4th 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 4th 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 = 3x10-3. The measurement results show good agreement with the simulation results.

Download Full-text

Inter-connected coupled lines Resonator topology for bandpass filter application

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v10i3.pp2523-2534 ◽

2020 ◽

Vol 10 (3) ◽

pp. 2523

Author(s):

Mohd Nasiruddin Hushim ◽

Norfishah Ab Wahab ◽

Tn. Syarifah Atifah Tn. Mat Zin ◽

Norlia Ghazali

Keyword(s):

Bandpass Filter ◽

Higher Order ◽

Coupled Line ◽

Microstrip Technology ◽

Half Wavelength ◽

Quarter Wavelength ◽

Coupled Lines ◽

In Series ◽

Tan Δ ◽

Filter Response

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, 2nd and 3rd order bandpass filters were fabricated using microstrip technology on Roger 3210 substrate with parameter of Ɛr = 10.2, h = 1.27 mm and tan δ = 3x10-3. The filters were measured and the results show good agreement with simulation results.

Download Full-text

Closed-loop ring resonator topology for bandpass filter applications

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v17.i3.pp1422-1426 ◽

2020 ◽

Vol 17 (3) ◽

pp. 1422

Author(s):

Norfishah Ab Wahab ◽

M. N. Md Tan ◽

M. N. Hushim

Keyword(s):

Transmission Lines ◽

Closed Loop ◽

Bandpass Filter ◽

Ring Resonator ◽

Single Mode ◽

Ring Structure ◽

Transmission Zeros ◽

Quarter Wavelength ◽

Coupled Lines ◽

Loop Ring

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 3rd order, simulated using full-wave electromagnetic simulator on microstrip substrate, FR-4 with characteristics given as Ԑr = 4.70, h = 1.499 mm and tan δ = 0.012. The filters are simulated and responses are found to be agreeable with the proposed idea.

Download Full-text

A Filtering Power Divider with Tunable Center Frequency and Wide Stopband

Frequenz ◽

10.1515/freq-2018-0261 ◽

2019 ◽

Vol 73 (9-10) ◽

pp. 301-306

Author(s):

Xuehan Hu ◽

Feng Wei ◽

Jiawen Hao ◽

Xiaowei Shi

Keyword(s):

Design Method ◽

Power Divider ◽

Center Frequency ◽

Electrical Length ◽

Transmission Zeros ◽

Quarter Wavelength ◽

Varactor Diodes ◽

Measurement Results ◽

Band Pass ◽

Good Agreement

AbstractIn this paper, a tunable power divider (PD) with a good band-pass filtering response using quarter-wavelength stepped impedance resonators (SIRs) is presented. By appropriately adjusting the impedance and electrical length ratio of SIR, the proposed structure can achieve wide stopband performance. Meanwhile, four varactor diodes are loaded to the external resonators to achieve electrical reconfiguration. In addition, a pair of transmission zeros (TZs) can be generated by applying source and load coupling on each side of the passband, which can effectively improve passband selectivity and out-of-band rejection. In order to verify the feasibility of the proposed design method, a prototype circuit of the proposed filtering power divider (FPD) with tunable center frequency is simulated, fabricated and measured. A good agreement between the simulation and measurement results is observed.

Download Full-text

Parallel-coupled stub-loaded resonator bandpass filter with ultra-wideband passband on multilayer liquid crystal polymer substrates

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078715001154 ◽

2015 ◽

Vol 8 (8) ◽

pp. 1183-1186 ◽

Cited By ~ 2

Author(s):

S. Almorqi ◽

H. Shaman ◽

A. Alamoudi

Keyword(s):

Liquid Crystal ◽

Bandpass Filter ◽

Liquid Crystal Polymer ◽

Ultra Wideband ◽

Center Frequency ◽

Coupled Line ◽

Crystal Polymer ◽

Quarter Wavelength ◽

Coupled Lines ◽

Chebyshev Filter

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.

Download Full-text

Compact dual-band bandpass filter using open stub-loaded stepped impedance resonator with cross-slots

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078715001786 ◽

2016 ◽

Vol 9 (2) ◽

pp. 269-274 ◽

Cited By ~ 7

Author(s):

Bukuru Denis ◽

Kaijun Song ◽

Fan Zhang

Keyword(s):

Bandpass Filter ◽

Design Concept ◽

Dual Band ◽

High Isolation ◽

Transmission Zeros ◽

Full Wave ◽

Measurement Results ◽

Stepped Impedance Resonator ◽

Simulation Results ◽

Good Agreement

A compact dual-band bandpass filter using stub-loaded stepped impedance resonator (SLSIR) with cross-slots is presented. The symmetric SLSIR is analyzed using even- and odd-mode techniques. Design equations are derived and they are used to guide the design of the circuits. Two passbands can be easily tuned by cross-slots and open stubs. Transmission zeros among each passbands are created, resulting in high isolation and frequency selectivity. An experimental circuit is fabricated and evaluated to validate the design concept. The fabricated filter is compact with 19.76 × 12.7 mm2. The measurement results are in good agreement with the full-wave simulation results.

Download Full-text

New Cad Model of the Microstrip Interdigital Capacitor

Active and Passive Electronic Components ◽

10.1080/08827510310001648870 ◽

2004 ◽

Vol 27 (4) ◽

pp. 237-245 ◽

Cited By ~ 11

Author(s):

Nihad Dib ◽

Qiu Zhangb ◽

Ulrich Rohde

Keyword(s):

Coplanar Waveguide ◽

Circuit Theory ◽

Closed Form Expression ◽

Simple Circuit ◽

Form Expression ◽

Coupled Line ◽

Interdigital Capacitor ◽

Quarter Wavelength ◽

Coupled Lines ◽

Good Agreement

A new model for the microstrip line interdigital capacitor is proposed. This model consists of calculating the2N×2N Y-matrix of theNcoupled lines using the multiple coupled line tool. Then, this matrix is reduced to a2×2matrix using simple circuit theory. The capacitance at the end of each finger is taken into consideration using closed-form expression of the coplanar waveguide open-end capacitance. This model can predict the resonances that might appear around the quarter-wavelength frequency. These resonances are caused by the coupling between the fingers and exist only in capacitors with four fingers or more. Very good agreement is obtained between the results of our model and those obtained using the software HFSS and measurements.

Download Full-text

Compact Bandpass Filter Based on Parallel-coupled Lines and Quasi-lumped Structure

Frequenz ◽

10.1515/freq-2015-0056 ◽

2016 ◽

Vol 70 (1-2) ◽

Author(s):

Chen Ding ◽

Jiao Li ◽

Feng Wei ◽

Xiao-Wei Shi

Keyword(s):

Bandpass Filter ◽

Quarter Wavelength ◽

Coupled Lines ◽

The Matrix ◽

Network Transformation ◽

Good Agreement

AbstractA compact microstrip bandpass filter (BPF) using quarter-wavelength resonators is proposed based on the parallel-coupled lines (PCLs) and quasi-lumped structure. A method based on the matrix and network transformation of cascaded-quadruplet (CQ) filters is investigated and successfully applied to the BPF design. The design formulas for the proposed BPF are analytically developed. Specifically, in order to verify the feasibility of the proposed method, three BPFs centering at 1.575 GHz with different FBWs are designed. Good agreement between the simulated and measured results is observed. Moreover, the designed filters can achieve a wide stopband.

Download Full-text

Wideband Band-Pass Filter Design Using Coupled Line Cross-Shaped Resonator

Electronics ◽

10.3390/electronics9122173 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2173

Author(s):

Dong-Sheng La ◽

Xin Guan ◽

Shuai-Ming Chen ◽

Yu-Ying Li ◽

Jing-Wei Guo

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Design Method ◽

Band Pass Filter ◽

Coupled Line ◽

Pass Filter ◽

Transmission Zeros ◽

Coupled Lines ◽

Band Pass ◽

Line Cross

In this paper, a wideband bandpass filter with a coupled line cross-shaped resonator (CLCSR) is proposed. The proposed bandpass filter is composed of two open-end parallel coupled lines, one short-end parallel coupled line, one branch microstrip line, and the parallel coupled line feed structure. With the use of the even and odd mode approach, the transmission zeros and transmission poles of the proposed bandpass filter are analyzed. The coupling coefficient of the parallel coupled line feed structure is big, so the distance between the parallel coupled line is too small to be processed. A three microstirp lines coupled structure is used to realize strong coupling and cross coupling. This structure also can reduce the return loss in passband and increase the out-of-band rejection. The transmission zeros can be adjusted easily by varying the lengths of the open-end parallel coupled line or the short-end parallel coupled line. The proposed bandpass filter is fabricated and measured. The simulated results agree well with the measured ones, which shows that the design method is valid.

Download Full-text

Design of differential-mode bandpass filter with common-mode suppression using ring dielectric resonator

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078716001306 ◽

2016 ◽

Vol 9 (5) ◽

pp. 1029-1035 ◽

Cited By ~ 2

Author(s):

Jugul Kishor ◽

Binod K. Kanaujia ◽

Santanu Dwari ◽

Ashwani Kumar

Keyword(s):

Dielectric Resonator ◽

High Performance ◽

Bandpass Filter ◽

Ring Resonator ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression ◽

Transmission Zeros ◽

System A ◽

Good Agreement

Synthesis of differential-mode bandpass filter (BPF) with good common-mode suppression has been described and demonstrated on the basis of ring dielectric resonator (RDR) for high-performance communication system. A RDR with two pairs of feeding lines has been used to excite TE01δ-mode. This unique combination of feeding lines and the ring resonator creates a differential passband. Meanwhile, TM01δ-mode of the DR can also be excited to achieve common-mode rejection in the stopband. Transmission zeros are created in the lower and upper stopband to further improve the selectivity of the proposed BPF. A second-order differential BPF is designed, fabricated and its performance is measured to validate the concept. There is good agreement between simulated and measured results.

Download Full-text

Compact dual-mode microstrip bandpass filter based on slotted square patch resonator

Microelectronics International ◽

10.1108/mi-08-2021-0080 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Karthie S. ◽

Zuvairiya Parveen J. ◽

Yogeshwari D. ◽

Venkadeshwari E.

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Center Frequency ◽

Dual Mode ◽

Content Type ◽

Transmission Zeros ◽

Compact Size ◽

Mode Response ◽

Better Than ◽

Good Agreement

Purpose The purpose of this paper is to present the design of a compact microstrip bandpass filter (BPF) in dual-mode configuration loaded with cross-loop and square ring slots on a square patch resonator for C-band applications. Design/methodology/approach In the proposed design, the dual-mode response for the filter is realized with two transmission zeros (TZs) by the insertion of a perturbation element at the diagonal corner of the square patch resonator with orthogonal feed lines. Such TZs at the edges of the passband result in better selectivity for the proposed BPF. Moreover, the cross-loop and square ring slots are etched on a square patch resonator to obtain a miniaturized BPF. Findings The proposed dual-mode microstrip filter fabricated in RT/duroid 6010 substrate using PCB technology has a measured minimum insertion loss of 1.8 dB and return loss better than 24.5 dB with a fractional bandwidth (FBW) of 6.9%. A compact size of 7.35 × 7.35 mm2 is achieved for the slotted patch resonator-based dual-mode BPF at the center frequency of 4.76 GHz. As compared with the conventional square patch resonator, a size reduction of 61% is achieved with the proposed slotted design. The feasibility of the filter design is confirmed by the good agreement between the measured and simulated responses. The performance of the proposed filter structure is compared with other dual-mode filter works. Originality/value In the proposed work, a compact dual-mode BPF is reported with slotted structures. The conventional square patch resonator is deployed with cross-loop and square ring slots to design a dual-mode filter with a square perturbation element at its diagonal corner. The proposed filter exhibits compact size and favorable performance compared to other dual-mode filter works reported in literature. The aforementioned design of the dual-mode BPF at 4.76 GHz is suitable for applications in the lower part of the C-band.

Download Full-text