4×4 rectangular patch array antenna for bore sight application of conical scan S-band tracking radar

This paper presents the design of 4×4 rectangular patch array antenna for the boresight application of S-band tracking radar with the centre frequency of 2.73 GHz. Corporate feed network is used in this array to excite uniform excitation distribution to obtain high gain and moderate side lobe levels. For impedance matching both inset fed and quarter wave impedance transformation techniques are used. Individual patch having dimension of 43.6×35.3 mm² with substrate of permittivity 2.2 and thickness of 3.175 mm is used. Impedance bandwidth of 250 MHz for VSWR less than 2 and gain of 18.4 dB with side lobe level better than -6.5 dB have been achieved. Structure is simulated using CST MICROWAVE STUDIO 2006 and appropriate results were found at an inset depth of 7.06 mm at each patch. S₁₁ of -25.43 dB is achieved at the resonant frequency of 2.736 GHz.