Effects of dielectric and magnetic materials on antenna performances of very small normal-mode helical antennas

Dielectric and magnetic materials are used frequently in very small normal-mode helical antennas for the purpose to minimize sizes and increase antenna performances. In this paper, effects to self-resonant structures are clarified. Modifications of self-resonant equations in using materials are studied. Effects to antenna efficiencies are also studied. It is shown that the magnetic materials are effective to increase antenna efficiencies. Moreover, the input impedance matching structure is shown for realization of an actual antenna.