Electrically Small Antenna for ELT in VHF and UHF bands

This paper presents the development results of an antenna for an emergency locator transmitter (EL T) that operates in the COSPAS-SARSAT system” s frequency range of 406.0-406.1 MHz., as well as at search and rescue frequencies of 121.5/243.0 MHz. The main challenge in designing such antenna is the need of meeting mechanical weight and size constraints., particularly the low antenna height requirement. The paper discusses the main challenges associated with electrically small antennas design., that are discussed with theoretically established fundamental limitations. The paper presents the results of simulation and experimental studies on the original design of an omnidirectional antenna., which is based on an inverted F -antenna. The measurements of the fabricated prototype showed good agreement with the calculated specifications simulation results. Thus., the developed EL T antenna was proved to be very prospective in multiband EL T with strict mechanical constraints.