Dual-Mode Symmetrical High-Frequency Antenna for Airborne Use

摘要

A compact, self-contained symmetrical antenna (experimental) for airborne use at high frequencies has been developed and tested. Provisions for tuning are integrated with the radiating elements. A four-port hybrid is incorporated enabling the antenna to function in two independent modes for both transmission and reception. When symmetrically installed on a helicopter and operated in the antiphase mode, excitation of the aircraft is minimized, and a dipole pattern which is predominantly horizontally polarized obtains. When operated in the inphase mode, the resulting pattern is omnidirectional and the polarization predominantly vertical. Radiation patterns are highly predictable and the rotor effect minimal. At frequencies in the lower HF range, the noval antenna has somewhat greater gain than the much larger conventional wire antenna. (Author)