Resumen
In this paper, we present the design and fabrication of two dual circularly polarized (CP) patch antennas that can be profitably used as feeders for reflector systems normally adopted for satellite applications. In the first part of the manuscript, we propose the optimization of a dual-CP patch antenna, loaded by a fence of passive monopoles around it to increase antenna gain for high elevation angles. To achieve dual-CP operation mode, the circular patch has been sequentially-fed by three pins, whose mutual phase-shift is equal to 120°" role="presentation">120°120°
120
°
. The antenna feeding network was placed on the antenna back and designed using microstrip technology. Two different input ports provide both right-hand (RH) and left-hand (LH) circular polarizations. A prototype of such an antenna was fabricated and measured at f=8.25" role="presentation">??=8.25f=8.25
f
=
8.25
GHz. Furthermore, to test the versatility of the proposed single radiating patch, in the second part of the manuscript, we present the results of geometrically scaling at f=2.2" role="presentation">??=2.2f=2.2
f
=
2.2
GHz (higher UHF band) and this was used as a building block for the design of a dual-CP sequentially-fed 2-by-2 array antenna. The results for both the proposed antennas are satisfactory in terms of impedance bandwidth, broad radiation pattern, gain and cross-polarization rejection, thus they can be profitably used as feeders for reflectors at relatively low frequencies.