The development of a dual polarised microstrip antenna for S- and C-band with improved characteristics is presented. It is dual linearly polarised at S-band and dual circularly polarised at C-band. Two orthogonal feeds have been conceived for proximity coupling at S-band. The other two composite feeds are aperture coupled at C-band. These generate left-hand and right-hand circular polarisations exclusively. The antenna reveals 3.5% or more impedance bandwidth at the S-band ports with an isolation better than 22 dB (the best isolation is ≈31.5 dB at the band-centre). It yields >21.2% impedance bandwidth and about 10.2% axial-ratio bandwidth at each of the C-band ports, both being improved compared to the earlier reports. Achieved isolation between the C-band ports is better than 18.5 dB (≈23.5 dB at the centre of the working band).