Novel antenna configurations for vehicle-borne NVIS applications

HF (3-30 MHz) propagation still has an important role to play in certain communication scenarios. Of particular importance is the so-called near vertical incidence skywave (NVIS) mode of propagation where the ionosphere is utilized for relatively short-range communication. This paper describes the analysis of a number of vehicle-borne NVIS antenna configurations. The moment method derived technique of characteristic modes is employed. This allows the treatment of any vehicle-antenna combination as one, by computing a unique set of orthogonal currents which may then be optimized to yield the required radiation pattern for the NVIS mode.<>