Date of Award
Summer 2000
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Electrical and Computer Engineering
First Advisor
Richie, James
Second Advisor
Jeutter, Dean
Third Advisor
Wolski, Mark
Abstract
The antenna characteristics and effectiveness of radio signal propagation from an aircraft are often influenced by large overhead rotating members, such as helicopter blades, which leads to degradation in performance. This thesis discusses high frequency (HF) antenna characteristics on a large cargo transport helicopter and the signal modulation effects caused by helicopter blade rotation. Antenna gain and signal fluctuation in the near vertical direction from the helicopter are considered for the normal radio frequency (RF) propagation mode. Various antenna configurations are reviewed using simulation and modeling in an effort to improve overall gain and reduce the amount of fluctuation. Antenna performance and dependence with blade rotation and frequency variation are reviewed. An insight into the electromagnetic fields present on the simulated helicopter is offered in an attempt to understand the gain and modulation effects for the various antenna configurations. The dependence of the radiated fields on the size and geometry of the antenna and helicopter is discussed. Ideas for improving signal gain using different antenna configurations and geometry are presented. The Chinook CH-47 helicopter and HF radio communication system provides a basis throughout this thesis for analyzing and understanding the rotor modulation effects. The analysis, ideas, and results may also apply to other helicopter communication systems.
Recommended Citation
Joda, Timothy P., "Electromagnetic Characteristics from An Aircraft Antenna System in the Presence of Rotating Members" (2000). Master's Theses (1922-2009) Access restricted to Marquette Campus. 4863.
https://epublications.marquette.edu/theses/4863