Following these ideas, originated from [10, 13], with the modifications first proposed in  and verified in , we here propose an internal impedance matching network for a helical antenna
which comprises a single wire.
Simulation of a four-arm spiral antenna for GPS result shows that considering the coaxial impedance matching connected coaxially to the helical antenna
can reduce the antenna geometries complexity.
D., "The helical antenna
," Proceedings of the IRE, Vol.
[12.] Kazama, Y., "A quadrifilar helical antenna
with parasitic loop," IEEE Antennas Propag.
A normal-mode helical antenna
(NMHA) has been studied for more than half a century, and the operation principles are well known by a simple equivalent model, proposed by Kraus and Wheeler, based on the assumption that the each turn is the superposition of electric and magnetic dipoles [1,2].
Capsalis, "Theoretical approach of the interaction between a human model and a mobile handset helical antenna
using numerical methods," Progress In Electromagnetics Research, Vol.
The helical antenna
is tuned to the lower frequency (900 MHz) band.
One approach to smaller antennas is the Contrawound Toroidal Helical Antenna
(CTHA) consisting of two or more helices wrapped around a toroidal core.
Within the transmitter, an electronics module links up with a helical antenna
embedded in a rugged polymer to send a radio-frequency signal to a receiver located in the operator's cab.
A very small normal-mode helical antenna
(NMHA) is the one having good performances with small size.