volume | PIER Journals

Abstract

This paper presents a compact broadband filtering antenna with wide stopband suppression performance. A quarter-wavelength shorted stub is integrated into the feeding structure to excite an additional low-frequency resonant mode and introduce a controllable transmission zero. Meanwhile, a parasitic patch is loaded to generate high-frequency resonant modes and upper-band transmission zeros, further expanding the impedance bandwidth. In addition, the hybrid integration of a dumbbell-shaped defected ground structure (DGS) and an open-circuited feed stub effectively suppresses high-order harmonic radiation, achieving wide stopband suppression. To clarify the multi-resonance coupling principle and inherent filtering mechanism of the integrated antenna configuration, a corresponding equivalent circuit model is established and analyzed. Measured results verify that the proposed filtering antenna achieves a broad impedance bandwidth of 19.01%, covering 3.76-4.55 GHz, with a peak realized gain of 6.35 dBi. Remarkably, the designed antenna achieves a wide stopband suppression range up to 3.07f₀ in the -10 dBi gain suppression level. The proposed filtering antenna is suitable for application in the extended frequency bands of 5G-Advanced.

1. Shibing, Zhang and Zhang Lijun, "Anti-interference ultra-wideband system based on spreading and interleaving," Journal of Systems Engineering and Electronics, Vol. 18, No. 2, 236-242, June 2007.
doi:10.1016/s1004-4132(07)60080-2 Google Scholar

2. Yang, Jian and Ahmed Kishk, "A novel low-profile compact directional ultra-wideband antenna: The self-grounded bow-tie antenna," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 3, 1214-1220, March 2012.
doi:10.1109/tap.2011.2180317 Google Scholar

3. Tang, Ching-Wen and Ming-Guang Chen, "A microstrip ultra-wideband bandpass filter with cascaded broadband bandpass and bandstop filters," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 11, 2412-2418, November 2007.
doi:10.1109/tmtt.2007.908671 Google Scholar

4. Lin, Chin-Kai and Shyh-Jong Chung, "A compact filtering microstrip antenna with quasi-elliptic broadside antenna gain response," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 381-384, 2011.
doi:10.1109/lawp.2011.2147750 Google Scholar

5. Li, Lei, Hui Dong Xiong, Wan Ying Wu, An Bang Fu, and Jia Ying Han, "A T-shaped strips loaded wideband filtering patch antenna with high selectivity," IEEE Antennas and Wireless Propagation Letters, Vol. 23, No. 1, 89-93, January 2024.
doi:10.1109/lawp.2023.3318223 Google Scholar

6. Yang, Dong, Huiqing Zhai, Chaozong Guo, and Hongkun Li, "A compact single-layer wideband microstrip antenna with filtering performance," IEEE Antennas and Wireless Propagation Letters, Vol. 19, No. 5, 801-805, May 2020.
doi:10.1109/lawp.2020.2980631 Google Scholar

7. Liu, Da, Qing Dong, Jun Xiang Wen, Liang Hua Ye, Duo-Long Wu, and Xiu Yin Zhang, "Compact wideband patch filtenna with enhanced out-of-band suppression," IEEE Antennas and Wireless Propagation Letters, Vol. 22, No. 9, 2310-2314, September 2023.
doi:10.1109/lawp.2023.3287350 Google Scholar

8. Chen, Husheng, Shiqiang Fu, Ziyi Shi, and Zhongbao Wang, "Broadband filtering patch antenna based on quad-mode resonance with high out-of-band rejection level," IEEE Antennas and Wireless Propagation Letters, Vol. 25, No. 3, 1354-1358, March 2026.
doi:10.1109/lawp.2026.3654632 Google Scholar

9. Yang, Wanchen, Yingqi Zhang, Wenquan Che, Mengzhu Xun, Quan Xue, Guangxu Shen, and Wenjie Feng, "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, October 2019.
doi:10.1109/tap.2019.2922770 Google Scholar

10. Zhou, Xin, Gang Zhang, Kam-Weng Tam, Huawei Lin, and Zhuowei Zhang, "Highly selective filtennas with wide-stopband based on multifunctional slots-loaded substrate-integrated cavity," IEEE Transactions on Antennas and Propagation, Vol. 72, No. 7, 5520-5529, July 2024.
doi:10.1109/tap.2024.3407379 Google Scholar

11. Chen, Xinwei, Li Zhao, Runbo Ma, Jinrong Su, and Wenmei Zhang, "Design and synthesis of a high-selectivity and wide stopband suppression filtering antenna with symmetric coupling structure," IEEE Antennas and Wireless Propagation Letters, Vol. 24, No. 2, 514-518, February 2025.
doi:10.1109/lawp.2024.3506626 Google Scholar

12. Hu, Yunfeng, Yuelong Wu, Gang Wang, and Xianliang Wu, "A circularly polarized, highly selective, harmonic-suppressed filtering antenna for 5G application," IEEE Antennas and Wireless Propagation Letters, Vol. 23, No. 12, 4308-4312, December 2024.
doi:10.1109/lawp.2024.3444284 Google Scholar

13. Zhang, Yongliang, Tianyu Liu, Linping Feng, Xianfang Zhang, and Sai-Wai Wong, "A coupling matrix synthesis design for filtering antenna with good out-of-band suppression," IEEE Antennas and Wireless Propagation Letters, Vol. 22, No. 7, 1582-1586, July 2023.
doi:10.1109/lawp.2023.3252560 Google Scholar

14. Li, Dajiang, Yong Ma, Kun-Zhi Hu, Zhiyuan Chen, Min Xiang, and Ming-Chun Tang, "A differentially fed dual-polarized filtering antenna with wide harmonic suppression for high-integration RF front ends," IEEE Antennas and Wireless Propagation Letters, Vol. 25, No. 2, 511-515, February 2026.
doi:10.1109/lawp.2025.3630629 Google Scholar

15. Mandal, M. K., P. Mondal, S. Sanyal, and A. Chakrabarty, "An improved design of harmonic suppression for microstrip patch antennas," Microwave and Optical Technology Letters, Vol. 49, No. 1, 103-105, November 2006.
doi:10.1002/mop.22049 Google Scholar

16. Guha, Debatosh, Sujoy Biswas, and Yahia M. M. Antar, "Defected ground structure for microstrip antennas," Microstrip and Printed Antennas: New Trends, Techniques and Applications, 387-434, D. Guha, Y. M. M. Antar eds., Wiley, October 2010.
doi:10.1002/9780470973370.ch12

17. Hong, Jia‐Sheng and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, June 2001.
doi:10.1002/0471221619

Dr. Xinwei Chen

Dr. Xingwang Xie

Dr. Jinrong Su

Dr. Guorui Han

Dr. Wenmei Zhang

Dr. Runbo Ma