Common Aperture Dual-Band Dual-Polarized Planar Microstrip Antenna

This paper presents the design of a common aperture dual-band microstrip antenna at 1.25and 2.5GHz. The antenna is dual-linear polarized at both the frequencies. The single antenna element configuration is probe-fed square annular patch at L-band and electromagnetically coupled stacked patch at S-band. L- and S-band patches are on separate layers and share the same aperture. A planar antenna has been designed using 2x 6 elements array at L-band and 4x 12 elements array at S-band. The antenna size is 0.36m x 1.1m. The measured peak gain is 16.9 dBi at 1.25GHz and 20.7 dBi at 2.5GHz. The cross-polarization and port to port isolations are better than 30dB at both the frequencies.