Fundamental Study of VHF Band Helical Antenna using Fe based Amorphous Composite

Abstract

A VHF band helical antenna using Fe based amorphous powder with a few µm diameter/epoxy composite material was fabricated. The composite material consisted of Fe based amorphous powder and epoxy resin, which had larger wavelength shorting effect due to the higher permeability and permittivity than those of free space. Fe based amorphous composite has miniaturization factor ((µ_r' ε_r')^1/2) of about 6-10 and normalized impedance ((µ_r'/ε_r')^1/2) of about 0.7-0.8 at 215 MHz (VHF band). This paper describes the magnetic/dielectric properties of composite materials and the radiation patterns of helical antenna with Fe based amorphous composite material.