Spiral microstrip antenna

• Main Author: Kee, Sen Chee.
• Other Authors: Lee Ching Kwang
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: http://hdl.handle.net/10356/17060
• Institution: Nanyang Technological University

In this knowledge based era, people thirst for information on the move. This is made possible with cellular network, wireless network, Bluetooth, WiMAX etc. Antennas are an integral part of these networks. However, antennas are generally unable to support such a wide range of frequencies for use by the different technologies. Hence this project aims to design and fabricate a Frequency Independent Antenna, commonly in the form of a Spiral Antenna which has a wideband capability to achieve a single antenna for all common communication technologies in the frequency band from 0.6 GHz to 7GHz. Antennas are required to be fed through various means with the input terminal port impedance typically of 50 Ω. However, the impedance of a spiral antenna is rarely 50 Ω hence the impedance of the antenna and the terminal impedance rarely match, resulting in transmission loss. The spiral antenna which is a balanced system is typically fed by a coaxial cable which is an unbalanced system, therefore a balun (balanced to unbalanced) has to be inserted between the spiral antenna and the coaxial cable. This balun includes an impedance matching circuit for impedance transformation from the spiral antenna impedance to the coaxial impedance. The objective of this final year project is to study on frequency independent antenna, the equiangular spiral antenna which has a wideband capability, and a wideband balun for use with the equiangular spiral antenna. The designs are simulated to predict the performance of the two components; the equiangular spiral antenna and the balun. The equiangular spiral antenna and the balun are fabricated and measured to verify its performance.