Analysis of Novel Approach to Design of Ultra-wide Stopband Microstrip Low-Pass Filter Using Modified U-Shaped Resonator

Karimi, Gholamreza; Lalbakhsh, Ali; Dehghani, Khatereh; Siahkamari, Hesam

doi:10.4218/etrij.15.0114.0188

Cited by 37 publications

(33 citation statements)

References 16 publications

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“…The values of the lumped elements are obtained using the procedure outlined in [53,54] In order to further investigate the frequency behavior of the proposed structure and predict and control the resonant frequencies, an equivalent lumped circuit model can be extracted for the structure. The use of lumped-element circuit (LC) models for analyzing microwave filters' behavior is a well-known approach and explained in [6,56,61,62]. The effect of the bends on the frequency response of the coupling system can be modeled by six capacitors (C bend ) as illustrated in a simplified lumped-element circuit (LC) model shown in Figure 3a.…”

Section: Proposed Coupling Systemmentioning

confidence: 99%

“…Additionally, capacitance and inductance of the open stub are presented by C O and L O , respectively. In order to calculate the lumped element values of this LC model, the method described in [6,56,61] can be used, in which the initial values are calculated [60] and then optimized to match the frequency responses of the LC model and the electromagnetic (EM) simulation. To lower the insertion loss of the second passband, a pair of stepped-impedance resonators, including a high impedance line and a low impedance open-end stub, are added to the BPF.…”

Section: Proposed Dual-band Bpfmentioning

confidence: 99%

“…Microstrip technology has been widely used in modern communication systems since it is a mature and highly reliable technology for microwave-and millimeter-wave applications [1][2][3][4][5][6][7][8][9][10][11]. In particular, multiband bandpass filters (BPFs) have been utilized in wireless communication transceivers to separate frequency spectrum in different bands.…”

Section: Introductionmentioning

confidence: 99%

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A Compact C-Band Bandpass Filter with an Adjustable Dual-Band Suitable for Satellite Communication Systems

et al. 2020

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A narrowband dual-band bandpass filter (BPF) with independently tunable passbands is presented through a systematic design approach. A size-efficient coupling system is proposed with the capability of being integrated with additional resonators without increasing the size of the circuit. Two flag-shaped resonators along with two stepped-impedance resonators are integrated with the coupling system to firstly enhance the quality response of the filter, and secondly to add an independent adjustability feature to the filter. The dual passband of the filter is centered at 4.42 GHz and 7.2 GHz, respectively, with narrow passbands of 2.12% and 1.15%. The lower and upper passbands can be swept independently over 600 MHz and 1000 MHz by changing only one parameter of the filter without any destructive effects on the frequency response. According to United States frequency allocations, the first passband is convenient for mobile communications and the second passband can be used for satellite communications. The filter has very good in- and out-of-band performance with very small passband insertion losses of 0.5 dB and 0.86 dB as well as a relatively strong stopband attenuation of 30 dB and 25 dB, respectively, for the case of lower and upper bands. To verify the proposed approach, a prototype of the filter is fabricated and measured showing a good agreement between numerically calculated and measured results.

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Section: Proposed Coupling Systemmentioning

confidence: 99%

Section: Proposed Dual-band Bpfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Compact C-Band Bandpass Filter with an Adjustable Dual-Band Suitable for Satellite Communication Systems

et al. 2020

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“…It should be noted that in Reference 19, an LPF, which is made up of open stubs and stepped impedance resonators, is firstly designed for which an artificial neural network is trained to enhance the specifications of the LPF, for instance in terms of sharpness. In another study, 20 using U‐shaped resonators and transfer function analysis, a high sharp LPF was reported, although having high VSWR can be considered as a negative point of this circuit. Using Z‐shaped resonator, a compact LPF with high figure of merit (FOM) was suggested in Reference 21.…”

Section: Introductionmentioning

confidence: 98%

New design of an adjustable compact microstrip lowpass filter using Z‐shaped resonators with low VSWR

Pahlavani

Moradkhani

Sayadi

2020

Micro & Optical Tech Letters

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In this article, an adjustable microstrip lowpass filter(LPF) with the cut‐off frequency (fc) at 1.59 GHz is designed and fabricated. The proposed structure is composed of a Z‐shaped resonator as basic resonator and a combination of modified T‐shaped and Z‐shaped resonators as suppressor units. To describe a theoretical design, the L‐C equivalent circuit of the basic resonator and also its transfer function are calculated precisely; then, the location of the first transmission zero (TZ) is accurately computed. Generating a deep TZ near the cutoff frequency leads to a high roll‐off rate of 195 dB/GH. The LPF also benefits from an extremely wide stopband from 1.72 to 23.67 GHz (15 fc). In passband region, the insertion loss and return loss of the LPF are 0.62 and 22.9 dB, respectively. The experimental results also show that maximum variation of group delay is only 0.53 ns regarding a negligible figure. The electrical size of the LPF is 0.187 × 0.083 λg2 (where λg is the guided wavelength at 1.59 GHz). Finally, the proposed LPF achieves a high figure of merit of 57 860 deemed a great accomplishment.

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“…Triangular patches along with meander line were used to generate lowpass response . The stub‐based filters are more popular for their compact size and better passband characteristics . But only a few could provide good out of band features.…”

Section: Introductionmentioning

confidence: 99%

Compact low‐cost microstrip lowpass filter with sharp roll‐off and wide attenuation band

Sen

Moyra

2019

Int J RF Microw Comput Aided Eng

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A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepped impedance resonator loaded with interdigital fingers and U-shaped resonator is recommended in this article. The proposed LPF has a cut-off frequency of 1.2 GHz with a sharp roll-off 135 dB/GHz and passband insertion loss 0.35 dB. An array of two different shapes of defected ground structures are etched in the ground plane for introducing additional transmission zeroes to enhance the stopband performance. The relative stopband suppression is achieved up to 171% with a suppression factor of 2. The proposed structure is modelled, fabricated, and measured. The measurement results are found to be well-matched with the simulated ones. Eventually, a high figure of merit of 21 600 is achieved. K E Y W O R D S defected ground structures, figure of merit, interdigital lines, lowpass filter, stepped impedance resonator, U-shaped resonator

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Analysis of Novel Approach to Design of Ultra-wide Stopband Microstrip Low-Pass Filter Using Modified U-Shaped Resonator

Cited by 37 publications

References 16 publications

A Compact C-Band Bandpass Filter with an Adjustable Dual-Band Suitable for Satellite Communication Systems

A Compact C-Band Bandpass Filter with an Adjustable Dual-Band Suitable for Satellite Communication Systems

New design of an adjustable compact microstrip lowpass filter using Z‐shaped resonators with low VSWR

Compact low‐cost microstrip lowpass filter with sharp roll‐off and wide attenuation band

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