A novel compact microstrip bandpass filter using folded open loop resonator is presented. The resonator elements are placed in close proximity to parallel coupled microstrip lines. The presence of undesired harmonics is eliminated here by properly modifying the configuration of the folded resonator. The measured and simulated results are in good agreement.
2. Kuo, J., S. Chen, and M. Jiang, "Parallel coupled microstrip filters with over coupled end stages for suppression of responses," IEEE Microwave and Wireless Component Letters, Vol. 13, No. 10, 440-442, 2003.
3. Kuo, J.-T., M. Jiang, and H. J. Chang, "Design of parallel coupled microstrip ¯lters with suppression of spurious resonances using substrate suspension ," IEEE Trans. Microwave Theory Tech., Vol. 52, No. 1, 83-89, 2004.
4. Velazquez, M. C., J. Marel, and F. Medina, "Parallel coupled microstrip filters with floating grounding plane conductor for spurious --- Band suppression," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 5, 1823-1828, 2005.
5. Cheong, P., S.-W. Fok, and K.-W. Tam, "Miniaturiaed parallel coupled --- Line bandpass filter with spurious-response suppression," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 5, 1810-1816, 2005.
6. Velazquez-Ahumada, M. C., J. Martel-Villagr, and F. Medina, "Microstrip coupled line filters with spurious band suppression," PIERS Online, Vol. 3, No. 6, 948-950, 2007.
7. Lopetegi, T., M. A. G. Laso, F. Falcone, F. Martin, J. Bonache, J. Garcia, L. Perez-Cuevas, M. Sorolla, and M. Guglielmi, "Microstrip wiggly-line bandpass filters with multispurious rejection," IEEE Microwave and Wireless Component Letters, Vol. 14, No. 11, 531-533, 2004.
8. Lin, H.-N., W.-L. Huang, and J.-L. Chen, "Miniaturization of harmonics-suppressed filter with folded loop structure," PIERS Online, Vol. 4, No. 2, 238-244, 2008.