Radiation Characteristics of Microstrip Array Antenna for X-band Radar Application

Microstrip antenna technology is currently widely used in various applications in the radar and telecommunications world, one of which is used for X-Band Radar application such as Vessel Traffic System (VTS) Radar Antenna. The choice of Microstrip Array Antenna is because this antenna type is simpler to array to obtain radiation characteristics like high directivity, high gain and narrow beamwidth which are needed for Radar Antenna specification. This paper discuss and analyze a 6 x 33 elements microstrip antenna subarray that can be used to form a full array antenna for X-band radar applications. The antenna is designed at frequency 9.4 GHz using FR4 substrate with thickness of 1.6mm and a dielectric permittivity of 4.3. The microstrip antenna has rectangular patch shape with series-corporate feed network, therefore no power combiner is used however the antena is designedto achieve a narrow horizontal beamwidth, large gain and low side lobe level. The radiation performance can be improved by using proper design structures. The simulation results of the microstrip array antenna with 6 x 33 elements using CST simulator are VSWR <= 1.5, gain >= 16 dBi, side lobe level <= -20 dB, horizontal beamwidth < 7.5, and Linier Radiation Pattern. It is shown from the simulation that the radiation characteristics of the proposed antenna satisfy with the requirement for a subarray. The proposed array antenna design is suitable for the X-Band Radar application due to the simplicity in structure, high gain, narrow beamwidth, and ease of fabrication.