Design of differential microstrip ring antenna

• Main Author: Cheong, Kai Xiang
• Other Authors: Zhang Yue Ping
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/150138
• Institution: Nanyang Technological University

Microstrip antennas have been widely studied and used for many years. It has many advantages like being light, small size and easy to fabricate which traditional antennas cannot offer. In recent years, the differential microstrip antenna has been gaining popularity for its low noise, low interference and being a solution to a single chip in radio systems. These characteristics eliminates the use of a lossy Balun which usually comes together with single ended microstrip antennas. In this Final Year Project, the study of a differential microstrip ring antenna operating at 5.2GHz will be conducted. The design of the differential microstrip ring antenna is based off the single-ended version. Hence, the study of single-ended microstrip ring antenna was necessary. Next, to design the microstrip ring antenna, the analysis and formulas for circular microstrip antenna was used because of the similarities between them. The feeding technique used to excite the antenna will be probe feeding because of its low spurious radiation and the ease for impedance matching. 2 probes will be used to excite the differential ring and are place opposite one another. It was found that the resonant frequency depends on how far apart the 2 ports are. The further away the higher the frequency. However, if it gets too close, the return loss was too high which was not ideal. Both single-ended and differential ring microstrip antenna demonstrated low bandwidths, 1.6% and 4.8% respectively, which is a known fact of microstrip antenna. To increase the bandwidth of the differential microstrip ring antenna, 2 orthogonal slits were cut out on the outer periphery of the ring. By doing so the bandwidth was increase to 7.92%. The dimensions of the slits were observed to affect both the resonant frequency and the bandwidth.