Compact Lowpass Filters With Sharp and Expanded Stopband Using Stepped Impedance Hairpin Units

Li, Lin; Li, Zheng‐Fan; Mao, Jun‐Fa

doi:10.1109/lmwc.2010.2047457

Cited by 77 publications

(52 citation statements)

References 5 publications

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“…However, it suffers from a gradual transition band and low level of stopband rejection. To expand the stopband region in the frequency response of LPFs, hairpin resonators can be utilized [2][3][4][5][6]. By utilizing this unit in [2], the stopband is expanded.…”

Section: Introductionmentioning

confidence: 99%

A Compact Microstrip Lowpass Filter With Sharp Roll-Off Rate and Ultra-Wide Stopband Employing Coupled Polygon Patches

Abdipour¹,

Abdipour²,

Lorestani³

2017

PIER C

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Abstract-In this paper, a microstrip lowpass filter with −3 dB cutoff frequency of 1.8 GHz composed of two resonators with different polygon patches and six symmetric suppressing cells is presented. To design the proposed filter, the impact of each microstrip transmission line on the scattering parameters of the employed resonators is separately determined by extracting the equations of the insertion loss (S 21 ) and return loss (S 11 ) on the basis of their equivalent LC circuit. The designed filter is fabricated and measured, and a good agreement between the results of simulation and measurement is obtained. In the whole stopband region, a return loss better than −0.35 dB and an acceptable suppression level of −22 dB from 1.87 to 19.75 GH are achieved. Furthermore, a flat insertion loss in the passband and an acceptable return loss (−19.32 dB) in this band can verify desired in-band performance. The designed lowpass filter has a high figure of merit about 36969.34.

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Section: Introductionmentioning

confidence: 99%

A Compact Microstrip Lowpass Filter With Sharp Roll-Off Rate and Ultra-Wide Stopband Employing Coupled Polygon Patches

Abdipour¹,

Abdipour²,

Lorestani³

2017

PIER C

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“…Lowpass filters (LPFs) are one of the most important components in modern microwave communication system. Many efforts have been explored to improve its performance, such as high rejection level, wide stopband and minimum size [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Cascading LPF units with different size is an effective method to extend stopband with a little size increase. Interdigital structure was embedded in low impedance section of stepped-impedance hairpin unit to control the transmission zeros location and improve stopband and transition property [5]. Two hairpin units with different size were cascaded to achieve wide stopband.…”

Section: Introductionmentioning

confidence: 99%

Compact LPF With Sharp Roll Off and Wide Stopband Using Coupling Stepped Impedance Triangular Resonator

Du¹,

Yang²,

Zhang³

et al. 2014

PIER Letters

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Abstract-A lowpass filter with sharp transition and wide stopband using a novel coupling steppedimpedance triangular resonator is presented. The L-C equivalent circuit is developed for designing this type filter and analyzing the mechanism for improving roll-off and rejection property. The stopband width, passband edge, roll-off rate and overall suppression level are affected by coupling capacitance. The effect of coupling capacitance is analyzed using calculated frequency response. Coupling triangular stubs provide adequate coupling capacitance resulting in balance among transition property, stopband width and suppression level easily. A single LPF unit is designed and fabricated with cutoff frequency of 860 MHz. The single LPF unit exhibits 40-dB suppression level from 1.11 GHz to 2.28 GHz. A cascaded LPF with three asymmetric units provides 40-dB suppression level from 1.1 GHz to 6.76 GHz, and rolloff rate of 154 dB/GHz with compact size as small as 0.23λ g × 0.05λ g , where λ g is guided wavelength at cutoff frequency.

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“…However, the filter with aperture is difficult to fabricate and have no diverse characteristics. As an alternative method, the hairpin resonator using the interdigital capacitors is presented in [4,5]. The internal coupling effect of the filter is depending on the interdigital capacitance, which is related to the finger number.…”

Section: Introductionmentioning

confidence: 99%

“…Increasing the number of the finger provides bigger capacitance for the low insertion loss, wide stopband, and sharp rejection. However, the filter needs to have a large size for the large number of the fingers with bigger capacitance [4,5].…”

Section: Introductionmentioning

confidence: 99%

Compact Microstrip Bandpass Filter Using Miniaturized Hairpin Resonator

Jun

Chang²

2013

PIER Letters

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Abstract-A compact microstrip bandpass filter using miniaturized hairpin resonators is presented in this letter. Two modified stepped impedance hairpin resonators connected by parallel coupling are designed for the bandpass filter. The proposed miniaturized hairpin resonator is composed of a microstrip line and rectangular ring structures between parallel high impedance lines. A big capacitance in the hairpin resonator is provided by the gaps of rectangular ring structures in the parallel high impedance lines. Therefore, the proposed bandpass filter using the hairpin resonators has a low insertion loss, low return loss and compact size. The proposed bandpass filter with a center frequency of 4.96 GHz is designed with EM full wave simulator IE3D and verified with experiment.

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Compact Lowpass Filters With Sharp and Expanded Stopband Using Stepped Impedance Hairpin Units

Cited by 77 publications

References 5 publications

A Compact Microstrip Lowpass Filter With Sharp Roll-Off Rate and Ultra-Wide Stopband Employing Coupled Polygon Patches

A Compact Microstrip Lowpass Filter With Sharp Roll-Off Rate and Ultra-Wide Stopband Employing Coupled Polygon Patches

Compact LPF With Sharp Roll Off and Wide Stopband Using Coupling Stepped Impedance Triangular Resonator

Compact Microstrip Bandpass Filter Using Miniaturized Hairpin Resonator

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