Isolation between electric and magnetic antennas in close proximity

• Main Author: Zhuang, Jingxin.
• Other Authors: Shen Zhongxiang
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/17977
• Institution: Nanyang Technological University

This final year report introduces the study of isolation between electric and magnetic antennas in close proximity. Monopole and slot antennas are used for electric and magnetic antennas respectively. Both antennas have been designed using High Frequency Structural Simulator (HFSS) and fabricated to verify the design concept. Measurement and simulation results are presented in this report for discussion. The report brings up the concept of combining electric and magnetic types of antennas. A combination of a quarter wavelength slot (magnetic antenna) and a quarter wavelength monopole (electric antenna) was designed to operate in a GSM frequency range. The slot antenna and monopole antenna were designed separately in advance before combining them together. Due to the high mutual coupling, methods of reducing the mutual coupling were also discussed. In a new configuration, a specially designed pattern of I-shaped slots in the system ground plane was introduced to reduce the mutual coupling between the two antennas. The slots effectively increase the path length of the current in the ground plane flowing between the antennas. To further improve the isolation, radiation arm of the monopole antenna was also designed to point out of the direction of the slot antenna. 30.8% and 19.3% of the return loss bandwidth for S11 and S22 parameter was obtained. The mutual coupling has been reduced from -2.55 dB to -8.33dB.