A Low-Pass Filter Based on the Slotted-Ground-Plane Horn-Shaped Resonator

ABSTRACT

Designs of a miniaturized low-pass filter (LPF) using the slotted-ground-plane resonator are introduced in this paper. The proposed filter consists of a horn-head slot in the ground plane, two modified arc-head resonators, and a parasitic patch connected at the microstrip line. The horn-head slot, which is a modified type of a horn-shaped slot, provides good band-stop characteristics. To enhance rejection performance, a pair of the modified arc-head slot is embedded inside the horn-head resonator to increase additional transmission zeros into frequency characteristics. Furthermore, a parasitically circular patch is added at the microstrip line for frequency reduction and rejection enhancement. The surface current distributions are presented to explain the resonance mechanism. For the proposed LPF, the measured rejection bandwidth over −20 dB is from 1.75 to 12.0 GHz.

KEYWORDS:

• arc-head slot
• horn-head slot
• slotted-ground-plane resonator
• transmission zero

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Notes on contributors

Chien-Jen Wang

Chien-Jen Wang. received the BS degree in electrical engineering from the National Sun-Yet-Sen University, Kaohsiung, Taiwan, in 1993 and the PhD degree from the National Chiao-Tung University, Hsinchu, Taiwan, in 2000. In 2000, he joined the Wireless Communication BU, BenQ Corporation, Taipei, Taiwan, R.O.C., as a project researcher, where he developed built-in antennas for handsets. In 2001, he joined the Department of Electrical Engineering, Feng-Chia University, Taichung, Taiwan, as an assistant professor and an associate professor in 2004. Since 2006, he has been joined the Department of Electrical Engineering, National University of Tainan, Tainan, Taiwan, as an associate professor, and became a professor in 2009. He is author and coauthor of more than 150 journals and conference proceeding papers. He serves on the editorial boards of the International Journal of Microwave Science and Technology, and he is an academic editor of British Journal of Applied Science & Technology. He is currently a senior member of IEEE. He is a reviewer for IEEE Transactions on Microwave Theory and Techniques, IEEE Transactions on Antennas and Propagation, IEEE Antennas and Wireless Propagation Letters, IET Microwaves, Antennas and Propagation, Journal of Electromagnetic Waves and Applications, and International Journal of Antennas and Propagation. His research activities involve the design and applications of RF/microwave circuits, antennas, and wireless communication systems.

E-mail: [email protected]