Analysis, design and measurement of a series-fed microstrip array antenna for X-band INDRA: The INDonesian maritime RAdar

A strategy to design and tunning of linear series center-fed patch array antenna as sub-array feed of a cylindrical reflector for INDRA (Indonesian maritime radar) is presented. INDRA is the first maritime radar built in Indonesia. The radar is a solid-state FMCW radar with operational frequency of 9.4 GHz. The antenna system of INDRA employs microstrip-patch-array offset-fed reflector antennas. The first field measurement of INDRA is scheduled to take place in September 2008. The design of an 1times8-elements sub-array is performed using a MOM based software simulator. A Number of arrays have been built and measured. A good agreement between the numerical and measurement results are observed at the center frequency. Return loss of better than -25 dB, and low sidelobe patterns with a maximum gain of 16 dBi were simulated and measured. A bandwidth of 200 MHz is observed for a return loss below -15 dB.