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PIERS Online
Vol. 4
No. 2
2008
pp: 238-244Miniaturization of Harmonics-suppressed Filter with Folded Loop StructureHan-Nien Lin, Wen-Lung Huang, and Jer-Long Chen doi:10.2529/PIERS070904042653 Downloads: 882 Abstract:In this paper we utilize a basic loop resonator to design and realize the bandpass filter, and then use the quarter-wavelength open stub to suppress the second and third harmonics. Electric and magnetic coupling in this filter will be realized by a narrow coupled gap and grounded via to achieve the transmission zeros in either the lower or upper stopband. Since the prototype of the original bandpass filter is a resonator-based one wavelength structure, it is slightly larger compared with the other proposed structures. We therefore utilize the folding loop structure of the circuit to achieve miniaturization. The 30% reduction of the circuit size is achieved. The circuit with folded structure not only can reduce the size but also can maintain the performance as original structure with only slight degradation on the third harmonic. The result of the measurement and simulation is in good agreement to provide an experimental verification on the compact filter design.References:1. Park, H.-J., J.-Y. Park, J.-C. Lee, J.-H. Kim, B. Lee, and N.-Y. Kim, "A new harmonic-suppressed tunable microstrip-ring bandpass filter," Microwave and Optical Technology Letters, Vol. 15, No. 1, 26-29, January, 2001. 2. Tu, W.-H. and K. Chang, "Compact microstrip bandstop filter using open stub and spurline," IEEE Microwave and Wireless Components Letters, Vol. 15, No. 4, 268-270, April, 2005. 3. Tang, C.-W. and H.-H. Liang, "Parallel-coupled stacked SIRs bandpass filters with open-loop resonators for suppression of spurious responses," IEEE Microwave and Wireless Components Letters, Vol. 15, No. 11, 802-804, Nov., 2005. 4. Choi, W.-W., K.-W. Tam, and R. P. Martins, "Spurious suppressed microstrip bandpass filter with two transmission zeros," Microwave and Optical Technology Letters, Vol. 48, No. 10, 1979-1981, October, 2006. 5. Zhou, J., M. J. Lancaster, and F. Huang, "HTS coplanar meander-line resonator filters with a suppressed slot-line mode," IEEE Transactions on Applied Superconductivity, Vol. 14, No. 1, 28-32, March, 2004. 6. Ahn, C.-S., J. Lee, and Y.-S. Kim, "Design flexibility of an open-loop resonator filter using similarity transformation of coupling matrix," IEEE Microwave and Wireless Components Letters, Vol. 15, No. 4, 262-264, April, 2005. 7. Ma, K., J.-G. Ma, S. Y. Kiat, and M. A. Do, "A compact size coupling controllable filter with separate electric and magnetic coupling paths," IEEE Trans. Microwave Theory Tech., Vol. 54, No. 3, 1113-1119, March, 2006. 8. Lei, M.-F. and H. Wang, "An analysis of miniaturized dual-mode bandpass filter structure using shunt-capacitance perturbation," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 3, 861-867, March, 2005. 9. Cheong, P., S.-W. Fok, and K.-W. Tam, "Miniaturized parallel coupled-line bandpass filter with spurious-response suppression," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 5, 1810-1816, May, 2005. 10. Chen, C.-F., T.-Y. Huang, C.-H. Tseng, R.-B. Wu, and T.-W. Chen, "A miniaturized multilayer quasi-elliptic bandpass filter with aperture-coupled microstrip resonators," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 9, 2688-2692, Sept., 2005. 11. Lee, J. and K. Sarabandi, "A miniaturized conductor-backed slot-line resonator filter with two transmission zeros," IEEE Microwave Wireless Components Lett., Vol. 16, No. 12, 660-662, Dec., 2006. |
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