UHF / VHF Antenna Design and Analysis for Automatic Deployable Emergency Beacons

This thesis focuses on antenna designed for Cospas-Sarsat (C/S) first generation beacons at two frequencies of operations, 121.5 MHz and 406 MHz. A variant of an Alford-loop antenna was designed and shown to have a maximum gain of 2 dBi with an omnidirectional pattern in the horizontal plane while the concept of switching phase relationship of signals illuminating two vertically stacked loop antennas was demonstrated. A size reduction of about 50% was achieved by folding the corners of the loop while maintaining the current phase along the loop constant. Additionally, a novel horizontally polarized compact slotted-loop antenna was introduced using the theory of slots and loop antennas resulting in an omnidirectional pattern in the azimuth plane having a maximum gain of 1.8 dBi. These antennas were designed to meet specifications imposed by C/S T.001 and ED-62A (Standards developed by EUROCAE).