Ultra-narrow bandwidth dual-band filter based on asymmetric step impedance resonator

A step impedance and resonator technology, applied in the field of ultra-narrowband dual-frequency filter, can solve the problems of high attenuation, microstrip dual-frequency filter can not achieve good frequency selection characteristics, large size, etc., to achieve high frequency selection characteristics , with the effect of low interpolation loss and small size

Inactive Publication Date: 2012-08-01
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a novel ultra-narrow-band dual It has four transmission zeros outside the passband, low insertion loss in the passband and high attenuation outside the passband, so as to achieve high frequency selection characteristics

Method used

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  • Ultra-narrow bandwidth dual-band filter based on asymmetric step impedance resonator
  • Ultra-narrow bandwidth dual-band filter based on asymmetric step impedance resonator
  • Ultra-narrow bandwidth dual-band filter based on asymmetric step impedance resonator

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Experimental program
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Embodiment 1

[0029] see figure 1 , the asymmetric step impedance ultra-narrow-band dual-band filter, comprising a dielectric substrate (2), a microstrip line (4) on the surface of the dielectric substrate (2), and a grounded metal coating (1) on the lower surface of the dielectric substrate; it is characterized in that The microstrip line (4) on the upper surface of the dielectric substrate is composed of two identical asymmetric step impedance resonators (A, B) and input and output feeders (3, 5); resonator A and resonator B are folded into a spiral structure, and are weakly coupled to each other; at the same time, the input and output feeders (3, 5) are also coupled and fed to the resonators (A, B) respectively.

Embodiment 2

[0031] This embodiment is basically the same as Embodiment 1, and the special features are as follows:

[0032] The length of each resonator (A, B) is one-half wavelength at the first center frequency, and both ends of each resonator (A, B) are open-circuited.

[0033] The input feeder and the output feeder (A, B) feed at 180 degrees.

[0034] The material of the microstrip line (4) and the ground metal plating layer (1) on the surface of the dielectric substrate (2) is gold, silver or copper with good electrical conductivity.

[0035] The dielectric substrate (2) has a dielectric constant of =2.65 of the dielectric board, the thickness of the dielectric board h =0.8mm.

Embodiment 3

[0037] Such as figure 1 Shown is the structure diagram of the ultra-narrowband dual-band filter based on the asymmetric step impedance resonator of this embodiment. The mutual coupling between resonator A and resonator B can generate two transmission zeros. At the same time, the position of the transmission zero point and the passband characteristics can be changed by adjusting the distance between the resonators. After design, simulation and optimization, the specific size of the microstrip ultra-narrowband dual-band filter is finally determined as follows:

[0038] L1=3.6mm, L2=5mm, L3=5.6mm, L4=5mm, L5=4.2mm, L6=3.2mm, L7=4mm,

[0039] L8=2.6 mm, L9=2.2 mm, L10=2 mm, L11=1.6 mm, L12=1.2 mm, L13=0.6 mm, L14=6 mm, L15=4.8 mm, L16=6.8 mm, W1=1.8 mm, W2=0.4 mm, W3=2 mm,

[0040] d1=d2=0.4 mm.

[0041] Based on the above method, a dual-band filter for wireless local area network (WLAN) is designed. Its center frequency is 2.4GHz / 5.22GHz, and the corresponding relative bandw...

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Abstract

The invention relates to an ultra-narrow bandwidth dual-band filter based on an asymmetric step impedance resonator. The ultra-narrow bandwidth dual-band filter comprises a medium substrate, a micro-strip line on the upper surface of the medium substrate and a grounding metal coating on the lower surface of the medium substrate. The micro-strip line on the upper surface of the medium substrate consists of two identical asymmetric step impedance resonators A and B, an input feed line and an output feed line. The resonator A is folded with the resonator B into a spiral shape, the resonators A and B are mutually coupled with each other in a weak manner, and the input and output feed lines are respectively coupled with the resonators A and B to feed. The dual-band filter in the embodiment has a small size and good frequency selectivity, low insertion loss inside a pass-band and high attenuation outside the pass-band can be realized, and the ultra-narrow bandwidth dual-band filter can be used for the design of a ultra-narrow bandwidth miniaturized dual-band filter in a wireless communication system.

Description

Technical field [0001] The invention relates to an ultra-narrow-band dual-band filter based on an asymmetric step impedance resonator, which belongs to the category of dual-band band-pass filters with miniaturization and high frequency selection characteristics in the technical field of wireless communication. Background technique [0002] With the rapid development of wireless communication systems, spectrum resources are increasingly scarce, and there is an urgent need for efficient spectrum utilization for dual-band or multi-band filters with high frequency selection characteristics, miniaturization, and low cost. The high frequency selection characteristic means that the transition from the passband to the stopband of the filter is very steep, and the return loss of the stopband should be as large as possible. In order to achieve high frequency selection characteristics, multiple transmission zeros are often introduced on one or both sides of the passband. The closer th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01P1/203H01P7/08
Inventor 肖中银黄春艳王业清李好储君君
Owner SHANGHAI UNIV
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