Electrical Performances of the Low Profile Normal Mode Helical Antenna in a Metal Proximity Use

摘要

The low profile small normal mode helical antenna that can be used above metallic plates has been developed. In this paper, the proximity effects of a metal plate on input impedances, self resonance conditions and radiation characteristics of the normal mode helical antenna are clarified through the electromagnetic simulation. The operating frequency of 953 MHz is selected. The objective antenna sizes of 0.03-0.05 wavelengths are studied. As parameters of the metal plate, existence of the metal plate, the spacing to the antenna and the sizes of metal plate are considered. Moreover, the simulated and measured results of the low profile normal mode helical antenna with tap feed are also discussed.