Design considerations for dual circularly polarized spherical phased array antenna at X-band for spacecraft data transmission

In this paper, design of a dual circularly polarized (CP) spherical phased array antenna (PAA) is discussed. Dual CP configuration is implemented to enable frequency reuse using polarization diversity. This is realized using a high performance dual CP radiating element. This antenna is capable to generate beams in both the polarizations at any specified direction over the hemisphere. Realization aspects and the measured results of the PAA are discussed here. This antenna is proposed to be used for the high bit-rate data transmission at X-band from the India's upcoming RADAR imaging satellite RISAT-1.