A Miniaturized Dual-mode Bandpass Filter using Triangular Loop Resonator with Wide Stopband by U-Shaped Defected Ground Structure (DGS)

Author(s):  
Supachai Chotjit ◽  
Sarawuth Chaimool ◽  
Prayoot Akkaraeakthalin
2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xuehui Guan ◽  
Ye Yuan ◽  
Lan Song ◽  
Xiaoyan Wang ◽  
Jiuhuai Lei ◽  
...  

A novel triple-mode bandpass filter (BPF) using a dual-mode defected ground structure (DGS) resonator and a microstrip resonator is proposed in this paper. The dual-mode characteristic is achieved by loading a defected T-shaped stub to a uniform impedance DGS resonator. A uniform impedance microstrip resonator is designed on the top layer of the DGS resonator and a compact bandpass filter with three resonant modes in the passband can be achieved. A coupling scheme for the structure is given and the coupling matrix is synthesized. Based on the structure, a triple-mode BPF with central frequency of 2.57 GHz and equal ripple bandwidth of 15% is designed for the Wireless Local Area Network. Three transmission zeros are achieved at 1.48 GHz, 2.17 GHz, and 4.18 GHz, respectively, which improve the stopband characteristics of the filter. The proposed filter is fabricated and measured. Good agreements between measured results and simulated results verify the proposed structure well.


2012 ◽  
Vol 512-515 ◽  
pp. 1115-1118
Author(s):  
Chien Min Cheng ◽  
Kai Huang Chen ◽  
Yuan Tai Hsieh ◽  
Fuh Cheng Jong ◽  
Shih Fang Chen

Aluminum Oxide microwave dielectric ceramics exhibit good microwave dielectric characteristics and suitable be used in the microwave devices. In this letter, using screen-printing technique and Ag/Pd paste, a novel dual-mode 2.4 GHz microstrip bandpass filter with U-shaped defected ground structure is screen printed on the Aluminum Oxide (Al2O3, relative dielectric constant=9.8) microwave dielectric ceramic substrate. In addition, a pair of input/output microstrip lines are designed to be 50 Ω and coupled to a λ/4×λ/4 square loop resonator. And in the ground plane, a U-shaped defected ground structure is used toλ excite the degenerate modes, which can be considered as a perturbation element to control the odd-mode frequency and -3 dB bandwidth of the bandpass filter. Finally, the coupling effects between these degenerate modes are presented and detailed investigated.


2014 ◽  
Vol 7 (6) ◽  
pp. 661-669 ◽  
Author(s):  
Hesham A. Mohamed ◽  
Heba B. El-Shaarawy ◽  
Esmat A.F. Abdallah ◽  
Hadia M. El-Hennawy

This work presents a novel frequency miniaturized reconfigurable dual-mode stub-loaded resonator switchable from bandpass filter to single/double-notched bandnotch filter. The proposed filter topology employs RF PIN diodes as the switching device. Based on the odd- and even-mode equivalent circuits, the resonant characteristics of the proposed microstrip resonator are investigated. The defected ground structure pattern enhanced the performance; the 3-dB bandwidth reached 63%, with insertion loss of −0.5 dB. There was great sharpness of 55 dB in the low-frequency edge (from 1.7982 to 1.8466 GHz) and 33 dB in the high-frequency edge (from 3.4329 to 3.4995 GHz). The frequency-reconfigurable microstrip filter has been designed, fabricated, and measured for application in narrow band and ultra-wideband.


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