A new miniaturized microstrip lowpass filter with compact size and a wide spurious-free stopband is investigated. To achieve compact design and ultra-wide band rejection, both triangular patch resonators and trapezoid patch resonators are introduced in the filter. To further reduce the circuit size of the filter, the meander transmission line is also adopted in the design. A demonstration filter with 3 dB cutoff frequency at 0.76 GHz has been designed, fabricated and measured. Results indicate that the proposed filter is able to suppress the 16th harmonic response referred to a suppression degree of 15 dB. Furthermore, the proposed filter exhibits a small size of 0.080λg×0.072λg, where λg is the guided wavelength at 0.76 GHz.
"Miniaturized Microstrip Lowpass Filter with Compact Size for Harmonic Suppression," Progress In Electromagnetics Research Letters,
Vol. 78, 59-63, 2018. doi:10.2528/PIERL18070507
1. Pozar, D. M., Microwave Engineering, 3rd Ed., 412-415, Wiley, New York, USA, 2005.
2. Li, J.-L., S.-W. Qu, and Q. Xue, "Compact microstrip lowpass filter with sharp roll-off and wide stop-band," Electron. Lett., Vol. 45, No. 2, 110-111, 2009. doi:10.1049/el:20093246
3. Li, L., Z.-F. Li, and Q.-F. Wei, "Compact and selective lowpass filter with very wide stopband using tapered compact microstrip resonant cells," Electron. Lett., Vol. 45, No. 5, 267-268, 2009. doi:10.1049/el:20092120
4. Ma, K. X. and K. S. Yeo, "New harmonic suppression low-pass filter using transformed radial stubs," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 3, 604-611, 2011. doi:10.1109/TMTT.2010.2095031
5. Hayati, M., A. Sheikhi, and A. Lotfi, "Compact lowpass filter with wide stopband using modified semi-elliptic and semi-circular microstrip patch resonator," Electron. Lett., Vol. 46, No. 22, 1507-1509, 2010. doi:10.1049/el.2010.2367
6. Wei, X.-B., P. Wang, M.-Q. Liu, and Y. Shi, "Compact wide-stopband lowpass filter using stepped impedance hairpin resonator with radial stubs," Electron. Lett., Vol. 47, No. 15, 862-863, 2011. doi:10.1049/el.2011.1414
7. Wei, F., L. Chen, X.-W. Shi, Q.-L. Huang, and X.-H. Wang, "Compact lowpass filter with wide stop-band using coupled-line hairpin unit," Electron. Lett., Vol. 46, No. 1, 88-90, 2010. doi:10.1049/el.2010.2411
8. Wang, J.-P., H.-F. Cui, and G. Zhang, "Design of compact microstrip lowpass filter with ultra-wide stopband," Electron. Lett., Vol. 48, No. 14, 854-856, 2012. doi:10.1049/el.2012.1362