Novel Spiral Antenna for GNSS Applications

Abstract

Spiral antennas are the most widely used antenna types which are frequency independent. And its wideband circular polarization characteristic, it is able to use in navigation systems. Most navigation systems are in the L band however if a military band is considered, the frequency band becomes 450 Mhz range which is the Global Navigation Satellite System Band. This study presents an Archimedean spiral antenna with novel integrated bead-shaped conductors to reduce the length of the arm and increase the gain. Bead-shaped conductors acting as a capacitor between arms of spiral, provide a broadband matching with 50 ohm and high gain. High impedance surface (HIS) which has periodically placed rectangular conductor reflects the backward signals within a phase. So there is no need for more length to enhance gain and lower the antenna dimensions. Measurements and simulations show that it is a high-performance antenna that meets the requirements. The designed antenna gain is over 6 dBic and the axial ratio is under 3 dB along the frequency range.