In this paper, a circular polarized patch antenna at NaviC and S-band is presented for Indian Regional Navigational Satellite System (IRNSS) receiver applications. For this application proposed antenna is satisfying the criteria of circular polarisation with a bandwidth of 2477 MHz to 2508 MHz. The shape of proposed antenna exhibits good gain which is required for the good operation of communication systems for IRNSS. Antenna is operating at frequency of 2492.08 MHz (S-band) with a return loss better than-15 dB and has the stable radiation pattern. For designing of this antenna a conducting patch of 27.5 mm x 27.5 mm and a FR-4 material with thickness of 1.6 mm and dielectric constant of 4.3 is used as a substrate material. In addition to this, the antenna is fed with a coaxial feed technique and matched with 50 Ω input impedance of antenna. The parameters like radiation pattern, VSWR, E field, gain and axial …