A Lowpass Filter Design Using Curved and Fountain Shaped Resonators

Frequenz ◽  
2019 ◽  
Vol 73 (7-8) ◽  
pp. 267-272 ◽  
Author(s):  
Sobhan Roshani ◽  
Khatereh Dehghani ◽  
Saeed Roshani
Keyword(s):  
Transmission Lines ◽  
Return Loss ◽  
Filter Design ◽  
Lowpass Filter ◽  
Transmission Zeros ◽  
Compact Size ◽  
Filter Response

Abstract In this paper a new lowpass filter (LPF) with curved line resonators and fountain shaped resonators is proposed. The proposed filter has achieved wide stopband, compact size, sharp roll-off rate and low return loss. Two tapered resonators are used to produce transmission zeros and widen the stopband. Also, a fountain shaped resonator is proposed using curved transmission lines to obtain good sharpness in the filter response. The cut-off frequency of the designed LPF is 1.74 GHz and the overall size of the designed LPF is 0.135 λg × 0.132 λg where λg is the guided wavelength at the cut-off frequency. The results show that the overall size of the lowpass filter could be reduced using curved line resonators and curved transmission lines.

A Compact Lowpass Filter with Four Transmission Zeros Using Single-Sided Compact Microstrip Resonator Cells

2012 ◽  
Vol 487 ◽  
pp. 125-129
Author(s):  
Kai Yu Zhao ◽  
Lin Li
Keyword(s):  
Insertion Loss ◽  
Return Loss ◽  
Cutoff Frequency ◽  
Lowpass Filter ◽  
Sharp Transition ◽  
Microstrip Resonator ◽  
Broad Bandwidth ◽  
Transmission Zeros ◽  
Compact Size ◽  
Low Insertion Loss

A compact lowpass filter using two single-sided compact microstrip resonator cells （CMRCs）with low insertion loss and broad bandwidth is presented. The cutoff frequency is about 1.4 GHz, the insertion loss is less than 0.6 dB and the 20dB bandwidth is up to the range from 2.1 GHz to 9.8 GHz by means of introducing four transmission zeros through two CMRCs. In addition, the simulated results demonstrate that the proposed filter is characterized by a compact size, low insertion loss, sharp transition, low return loss and wide bandwidth.

Miniaturized dual-band filter with return loss bandwidth and transmission zero control

2017 ◽  
Vol 9 (7) ◽  
pp. 1459-1465
Author(s):  
Di Lu ◽  
N. Scott Barker ◽  
Xiao-Hong Tang
Keyword(s):  
Return Loss ◽  
Filter Design ◽  
Frequency Control ◽  
Magnetic Coupling ◽  
Dual Band ◽  
Center Frequency ◽  
Transmission Zeros ◽  
Simple Strategy ◽  
Compact Size ◽  
High Flexibility

In this paper, a compact dual-band bandpass filter (DB-BPF) using new dual-mode resonator-loaded resonators (DM-RLRs) is presented and investigated to simultaneously achieve controllable return loss (RL), bandwidth (BW) and transmission zeros (TZs), and the simple strategy for this type of filter design is proposed. The DB-BPF consists of two high-flexibility DM-RLRs with separated electric and magnetic coupling (SEMC). Specifically, the proposed DM-RLR provides the DB-BPF with center frequency control as well as RL control, and SEMC is utilized for the BW and TZ control. To facilitate the design, a simple optimization-based design strategy is proposed and employed, resulting in an example layout. Finally, the example filter, with center frequencies of 1.57 GHz (channel 1 for GPS) and 3.5 GHz (channel 2 for WiMAX), is fabricated and measured. The measurement insertion loss and RL are 0.9/0.9 and 17/20 dB. The fabricated DB-BPF also exhibits a compact size of 0.12λg × 0.08λg at 1.57 GHz.

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

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.

A novel compact lowpass filter with sharp roll-off and wide stopband

2019 ◽  
Vol 12 (1) ◽  
pp. 21-33
Author(s):  
M. Hayati ◽  
AS. Abdipour ◽  
AR. Abdipour
Keyword(s):  
Transmission Lines ◽  
Lowpass Filter ◽  
Transmission Zeros ◽  
High Impedance ◽  
Attenuation Level ◽  
Measurement Results ◽  
High Figure ◽  
Frequency Behavior ◽  
Better Than ◽  
Resonance Cell

AbstractIn this paper, a microstrip lowpass filter adopting two main resonators with steep transition band and wide rejection band has been introduced. The first main resonance cell consists of meandered transmission lines which are loaded by modified T-shaped patches. The second main resonator is composed of high-impedance lines loaded by polygon patches. To obtain a steep skirt performance, the first and second resonators have been combined. Moreover, employing eight high–low impedance folded stubs and two rectangular open-stubs as suppressing cells has resulted in improving the stopband features. To comprehend the frequency behavior of the employed resonators and also their combination, the formulas of the transmission coefficient, reflection coefficient, and the transmission zeros of their equivalent LC circuits have been extracted, separately. According to the measurement results, the −3 dB operating frequency of this filter is 1.65 GHz. Moreover, a relative stopband bandwidth equal to 166% with a corresponding attenuation level of 23 dB and a sharp roll-off rate (393.61 dB/GHz) have been achieved. In the passband region from DC to 1.632 GHz, the insertion loss and return loss are better than 0.0763 and 15.85 dB, respectively, proving an acceptable in-band performance. Finally, the implemented structure brings about a high figure-of-merit equal to 81 672.

Two- and Four-Pole Multilayer SIW Filter with High Selectivity and Higher-Order Mode Suppression

Frequenz ◽  
2019 ◽  
Vol 73 (5-6) ◽  
pp. 209-217 ◽  
Author(s):  
Dinghong Jia ◽  
Quanyuan Feng ◽  
Qianyin Xiang
Keyword(s):  
High Selectivity ◽  
Filter Design ◽  
Design Method ◽  
Single Layer ◽  
Cross Coupling ◽  
Bandpass Filters ◽  
Coupling Scheme ◽  
Transmission Zeros ◽  
Compact Size ◽  
Spurious Mode

Abstract This letter presents an approach to design two-pole source-load coupling and four-pole cross-coupling substrate integrated waveguide (SIW) bandpass filters based on multilayer process. Utilizing the field distribution, the vertical magnetic and electric coupling of fundamental mode is designed by suppressing the first spurious mode. Then, source-load and cross-coupling schemes are realized with controllable features in two-pole and four-pole filters, respectively. The harmonic passband produced by TE102 mode can be suppressed by proper coupling technique enabling the connection with TE102 mode in two- and four-pole filter designs, respectively. Three transmission zeros, which are derived from source-load coupling, are introduced around the passband of two-pole filter to improve its selectivity. In the four-pole filter design, a six-order cross-coupling scheme including source and load produces four transmission zeros around the passband, leading to a sharp selectivity. In addition, another transmission zero is generated at the adjacent location of the passband to improve the out-of-band rejection. Compared with conventional horizontally coupled filters made of single layer, the proposed filters show a compact size. To demonstrate the proposed design method, a two-pole and a four-pole double-layered SIW bandpass filters are fabricated and measured. Measured results show that the proposed filters exhibit high selectivity and good out-of-band rejection, as well as a good agreement between simulated and measured results.

scholarly journals CASCADED SQUARE LOOP BANDPASS FILTER WITH TRANSMISSION ZEROS FOR LONG TERM EVOLUTION (LTE)

SINERGI ◽  
2018 ◽  
Vol 22 (1) ◽  
pp. 63
Author(s):  
Iis Andini ◽  
Dian Widi Astuti ◽  
Muslim Muslim
Keyword(s):  
Insertion Loss ◽  
Return Loss ◽  
Bandpass Filter ◽  
External Resonator ◽  
Transmission Zeros ◽  
Term Evolution ◽  
Compact Size ◽  
Measurement Results ◽  
Resonator Method

In this paper, we present a bandpass filter that passed frequency of 1.7 GHz – 1.8 GHz. It is applied for an uplink frequency in 4G 1800MHz. This filter is created by using substrate PCB TMM-10i and has a compact size of 42 mm x 42 mm. The compact size is also important besides selectivity. The selectivity is achieved by implementing cascade square loop resonator method which generated transmission zeros. Actually, transmission zeros are obtained from the coupled resonator. The bandpass filter is designed by adding an external resonator on each square of the resonator loop and a patch to the inside of the square loop resonator. The parameter performances are simulated by HFSS. The parameter performances for return loss value is 14.24 dB at frequency 1.75 GHz and insertion loss value is 0.65 dB at frequency 1.75 GHz. By using VNA Anritsu MS 2026A, prototype bandpass filter is measured. The measurement results for return loss value is 6.8 dB and insertion loss value is 2.2 dB.

Compact Lowpass Filter Design on Double-layered DGS Transmission Lines

2020 ◽  
Vol 69 (12) ◽  
pp. 1898-1903
Author(s):  
Young Joo Kim ◽  
Dongho Seo ◽  
Won-Sang Yoon ◽  
Sang-Min Han
Keyword(s):  
Transmission Lines ◽  
Filter Design ◽  
Lowpass Filter

Microstrip lowpass filter with wide stopband and sharp roll-off using modified radial stub resonator

2016 ◽  
Vol 9 (3) ◽  
pp. 499-504 ◽  
Author(s):  
Mohsen Hayati ◽  
Mehrnaz Khodadoost ◽  
Hamed Abbasi
Keyword(s):  
Transmission Lines ◽  
Insertion Loss ◽  
Return Loss ◽  
Lowpass Filter ◽  
Transition Band ◽  
Attenuation Level ◽  
Radial Stub ◽  
Better Than ◽  
Good Agreement

In this paper, a microstrip lowpass filter with wide stopband and sharp roll-off is presented. The proposed filter consists of a modified radial stub resonator which is cascaded by four suppressing cells. To reduce the overall size, the transmission lines are folded. The cut-off frequency of the proposed filter is 1.19 GHz. The transition band is approximately 0.2 GHz from 1.19 to 1.39 GHz with corresponding attenuation levels of 3–20 dB. The stopband is from 1.39 to 19 GHz with attenuation level of <20 dB. The insertion loss and return loss in the passband from DC to 0.8 GHz are better than 0.26 and 14 dB, respectively. The proposed filter is fabricated and measured. The simulated and measured results are in good agreement.

Design of Novel Compact Quad-Band Bandpass Filter with High Selectivity

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 53-59
Author(s):  
Qingchun Cao ◽  
Hui Liu ◽  
Li Gao
Keyword(s):  
Return Loss ◽  
High Selectivity ◽  
Bandpass Filter ◽  
Center Frequency ◽  
Transmission Zeros ◽  
Compact Size ◽  
Left And Right ◽  
Embedded Structure ◽  
Better Than ◽  
Good Agreement

AbstractThis paper presents a compact quad-band bandpass filter. The filter is realized by multi-embedded stub-load resonators. By utilizing multi-embedded structure, the whole filter exhibits a compact size. And due to the multi-section stub-loaded lines, four passbands can be realized and the center frequency of the four passbands can be controlled individually to accommodate different communication protocols. Moreover, by using 0° degree feed structure, there are two transmission zeros locates at left and right side of a passband, which greatly enhance the selectivity. To validate the proposed idea, a quad-band bandpass filter, which operates at 2/2.7/3.45/4.55 GHz is implemented. The insertion loss is smaller than 2 dB and return loss is better than 10 dB. Good agreement between the predicted and measured results demonstrates the proposed idea.

scholarly journals New design of wideband microstrip branch line coupler using T-shape and open stub for 5G application

2021 ◽  
Vol 11 (2) ◽  
pp. 1346
Author(s):  
Ali Abdulateef Abdulbari ◽  
Sharul Kamal Abdul Rahim ◽  
Mohamad Zoinol Abidin Abd Aziz ◽  
K. G. Tan ◽  
N. K. Noordin ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Communication Systems ◽  
High Performance ◽  
Return Loss ◽  
Coupling Factor ◽  
Center Frequency ◽  
Branch Line ◽  
High Impedance ◽  
Compact Size ◽  
Simple Difference

A new design of wideband branch-line coupler (BLC) using T-shape with open stub microstrip line is proposed. The branch line coupler is integrated with low and high impedance λ/4 transmission lines to achieve the comparatively compact size of (27.2 mm × 16.5 mm). operating the bandwidth in simulated of BLC from 2.9 to 4 GHz is obtained 30.22% with a frequency center of 3.5 GHz. Meanwhile, the measured bandwidth of the BLC is cover from 2.8 GHz to 4.22 GHz is equal 33.40% at the center frequency 3.55 GHz respectively. The BLC simulated has low isolation and high return loss of -29.28 dB and -30.69 dB at the center frequency 3.5 GHz.Whereas, the measured result has a simple difference in the return loss and isolation are -27.43dB and -24.46 dB at the frequency 3.55GHz respectively. This BLC design has a good coupling factor of -2.97 and insertion loss of -3.65 dB. Furthermore, it obtains an excellent amplitude and phases different between two output of ±0.1 and 93.6°±3.4° with high performance. There is a good agreement between the simulated result and the measured result. This branch line coupler design used for 5G applications for future wireless communication systems.

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