In this paper, a wide harmonic suppression filtering antenna with high selectivity is designed. The filtering antenna adopts dual-layer structures. By introducing four parasitic patches around the top driven patch, the impedance bandwidth is widened. Moreover, the current directions on the driven patch and the parasitic patches are opposite in some frequency, so that the radiation null is introduced. In addition, a rectangular split ring DGS is etched in the middle of the ground plane, the lower sideband radiation null is introduced. Two sets of dumbbell-shaped defected ground structures are etched on the ground plane of the intermediate layer. The high-order harmonics are suppressed, and another radiation null is introduced. The experimental results show that the antenna operates at 2.46-2.66 GHz; the relative bandwidth is 7.8%; the peak gain is 3.8 dBi; and the S11 is more than -3 dB at 3-13 GHz.
2. Jin, J. Y., S. Liao, and Q. Xue, "Design of filtering-radiating patch antennas with tunable radiation nulls for high selectivity," IEEE Transactions on Antennas and Propagation, Vol. 66, No. 4, 2125-2130, 2018.
3. Zhang, Y., et al., "A wideband filtering patch antenna with multiple radiation nulls for good stopband suppression," 2019 IEEE MTT-S International Wireless Symposium (IWS), 1-3, IEEE, 2019.
4. Yang, W., et al., "A simple, compact filtering patch antenna based on mode analysis with wide out-of-band suppression," IEEE Transactions on Antennas and Propagation, Vol. 67, No. 10, 6244-6253, 2019.
5. Qin, K., F. Fan, and L. Wang, "Compact planar wideband filtering antenna with stopband suppression by loading defected ground structure," 2020 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 1-3, 2020.
6. Guan, X., et al., "A double-layer filtering antenna based on composite resonator with multiple radiation nulls," 2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 1-3, 2019.
7. Yang, D., et al., "A compact single-layer wideband microstrip antenna with filtering performance," IEEE Antennas and Wireless Propagation Letters, Vol. 19, No. 5, 801-805, 2020.
8. Liu, P., et al., "Wideband omnidirectional filtering antenna with CSRR loading," 2019 IEEE Asia-Pacific Microwave Conference (APMC), 1197-1199, 2020.
9. Liu, P., et al., "Wideband multi-mode filtering circular patch antenna," IEEE Transactions on Antennas and Propagation, Vol. 69, No. 11, 7249-7259, 2021.
10. Zhang, X. Y., W. Duan, and Y. M. Pan, "High-gain filtering patch antenna without extra circuit," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 12, 5883-5888, 2017.
11. Liu, G., Y. M. Pan, and X. Y. Zhang, "Compact filtering patch antenna arrays for marine communications," IEEE Transactions on Vehicular Technology, Vol. 69, No. 10, 11408-11418, 2020.
12. Choudhary, D. K., N. Mishra, P. K. Singh, and A. Sharma, "Miniaturized power divider with triple-band filtering response using coupled line," IEEE Access, Vol. 11, 27602-27608, 2023.
13. Wen, L. H., et al., "A wideband differentially fed dual-polarized antenna with wideband harmonic suppression," IEEE Transactions on Antennas and Propagation, Vol. 67, No. 9, 6176-6181, 2019.
14. Fan, J., et al., "Ultra-wideband harmonic suppression of microstrip antennas using compact defected ground structure," 2020 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 1-3, IEEE, 2020.
15. Chen, C. C., et al., "Microstrip-fed circular ring-slot antennas with very wideband harmonic suppression," IEEE Antennas and Wireless Propagation Letters, Vol. 19, No. 12, 2295-2299, 2020.
16. Qian, J. F. and F. C. Chen, "A multi-mode resonator-fed broadband patch antenna with improved selectivity and harmonic suppression," 2018 Asia-Pacific Microwave Conference (APMC), 1594-1596, 2018.
17. Yuan, H. and F. C. Chen, "A novel filtering patch antenna with wide stopband and improved selectivity," 2020 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 1-3, 2020.
18. Hou, R., et al., "Magnetoelectric dipole filtering antenna based on CSRR with third harmonic suppression," IEEE Antennas and Wireless Propagation Letters, Vol. 20, No. 7, 1337-1341, 2021.