Design and Evaluation of Transmit and Receive Antennas for an Ionospheric Communications Probe System: A. Multiband Dipole Antenna.

摘要

This thesis reports the design, performance evaluation and construction of a transmitting antenna for an HF communications probe system. A short range-ionospheric communication link between Monterey, CA, (transmit site) and San Diego, CA, (receive site) was established to test the software and hardware of this probe system. The Multiband Dipole Antenna was selected as the more practical antenna for this link, using less real estate and support structure than other alternatives. The antenna was constructed and installed at the NPS beach site where the ground constants were measured accurately. Numerical Electromagnetics Code (NEC) analysis and measurements show that the antenna operates with low input VSWR (<1.5), is insensitive to electrical ground characteristics and has excellent radiation patterns for short range ionospheric communication links. Based on the observed signal strengths at San Diego, the antenna appears to be performing very well.