Novel Low-Spread Phase-Center Patch Antenna for GNSS Applications
Erez Ben-Ari, Elina Mihlin, Tom Berko, Hamutal Tzayada, Ben-Zion Joselson
9 October 2011
Phase-Center, Global Navigation Satellite Systems, Attitude Determination Systems
A novel printed-circuit patch antenna for high accuracy Global Navigation Satellite Systems (GNSS) applications for the L1 frequency is presented. The antenna consists of an annular patch short-circuited on the outer perimeter while the inner radiating boundaries are left open. Four 90° sequentially rotated feeds are used to feed the antenna for circular polarization. This ensures a confined radiating area and improved symmetry; hence a low phase-center variation and polarization purity are achieved for observers across the upper half plane. The notion and definitions of the loose term “Phase-Center” are critically discussed, and calculation of antenna phase-center apparent positions, based on simulated and measured electromagnetic fields, is presented. A preferred practical statistical approach is taken, so that antennas can be assessed regarding stability of their phase-center apparent positions. Simulations for high-er versions of the new antenna show that phase-center position stability may be improved down to a few mm (weighted RMS) if antenna symmetry and continuity of shape are adhered to.
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