Effects of Dielectric Materials on Impedance Characteristics of Embedded Small Normal Mode Helical Antenna

The normal mode helical antenna (NMHA) is widely selected on RFID and wireless communication applications and often placed in a dielectric material for protection and miniaurization design. In this paper, the effects of dielectric materials with finite dimension on resonant frequency and impedance characteristics of embedded small NMHA were investigated. Three parameters related to the dielectric material were considered. Significant results were obtained by varying each one of these electrical dielectric parameters. It provides an effective guidance for designers to tune the antenna to desirable complex impedance when surroundded dielectric materials are employed.