<p>This paper presents a compact dual-band circularly polarized shared aperture antenna operating at the L5 and S bands for NavIC (Navigation with Indian Constellation) application. The shared aperture design enables the antenna to radiate simultaneously at both frequency bands, while the circular polarization ensures a robust and reliable signal reception. The proposed antenna is designed using a multilayer stacked structure, containing a circularly polarized square loop on the top layer operating from 1.14 to 1.19 GHz covering the L5 band and a corner truncated patch in the middle layer operating from 2.36 to 2.51 GHz in S-band. Circular polarization in L5-band and S-band can be achieved with orthogonal feed via a balun-structured power divider and a corner truncated square patch, respectively. The power divider for L5 band is designed on the back side which overcomes the effect of spurious radiations. In place of direct feed to L5 band loop, it is fed through an electromagnetically coupled rectangular strip, providing better beamwidth and improving axial ratio. In the presented geometry radiators are designed at different heights with the same physical space which reduces coupling between the elements, providing isolation better than 20dB. Moreover, the antenna has a compact size of 75 × 75 × 8 mm³ and exhibits wide axial ratio bandwidth (3-dB ARBW) in both the L5-band and S-band. The results demonstrate that the proposed antenna provides good radiation characteristics, low cross-polarization levels, and excellent impedance matching over the entire frequency band.</p>