Design of miniaturized log-periodic dipole antennas

• Main Author: Ning, Linglin
• Other Authors: Shen Zhongxiang
• Format: Theses and Dissertations
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/64774
• Institution: Nanyang Technological University

With the rapid development of wire less communication, antenna miniaturization has been a hot topic m the past ten or twenty years so that increasing requirement has been proposed for miniaturized antennas. Miniaturization of log-periodic dipole antennas (LPDA) is studied at very high frequency (VHF) band in the dissertation, based on antenna and microwave circuit theories. A printed LPDA in a traditional design proposed by R. Carrel is firstly discussed for the specified electrical and mechanical specifications. Then two types of antenna miniaturization methods are employed according to the traditional design of LPDA. One is to use meander structure by folding the longer dipoles to directly decrease the length of dipoles; the other is to load the antenna with dielectric materials. Compared to the traditional LPDA, the corresponding dimensions of folded LPDA are optimized by HFSS simulation. Then the antenna is redesigned using the software by loading with different dielectric material. Their radiation characteristics are discussed and compared through HFSS simulating. The results have indicated that all of the three designs meet the requirements while the folded LPDA achieves a 40% size reduction, compared to the traditional one and the dielectric loaded LPDA reduces its size by 70%.