Design of conformal log periodic monopole array antennas

• Main Author: Zhang, Liping
• Other Authors: Lu Yilong
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: http://hdl.handle.net/10356/53274
• Institution: Nanyang Technological University

While it is necessary for most types of log periodic antennas to have a half wavelength dimension, this report presents a broadband, frequency-independent, end-fire antenna that reduces its maximum height to a quarter of wavelength at its lowest operating frequency by utilizing its image below the perfect ground plane to provide the other half of the structure. The relatively small dimension of this antenna is desirable in the HF communication systems. A systematic design method is developed for LPMA (log periodic monopole antenna). Theories and calculation that are necessary for the design of geometry and feed line of the antenna to achieve the best performance are discussed. In addition, the matlab programs developed in this study allow future designers to easily derive the configuration and feed line parameters of a LPMA with N elements. While N could have many values, this project sets N to be 12 and designs an optimum model of 12 monopoles that has the best performance. A large number of models have been built and simulation has been run by utilizing a software suite called FEKO. Radiation patterns, phase center and S11 parameter are provided in the results of simulation. Finally, the simulation results are evaluated and a LPMA model with the best simulation performance is presented in this report.