High directivity FR4 substrate slotted defected ground microstrip patch antenna for X-band applications

The paper emphasizes on the design and performance analysis of high directivity FR4 substrate slotted defected ground microstrip patch antenna for X-Band applications. The antenna has been fed by microstrip feedline via impedance transformer to match the impedance of proposed antenna with the 50Ω impedance of co-axial connector used for feeding power to the antenna. The propounded antenna has been devised and simulated in CST Microwave Studio 2014. This antenna resonates at frequency of 7.94 GHz with the minimal return loss of -81.25 dB, high gain of 8.5 dB and directivity of 8.12 dBi. The proposed antenna has been designed using Flame Retardant 4 (FR4) substrate of dielectric constant, ε
_r
=4.4 sandwiched between copper patch and ground plane. The designed antenna has compact area and operating bandwidth of 560 MHz (7.67 GHz-8.22 GHz). The designed antenna can be suitably employed for X-band applications-military, satellite to earth downlink, earth to satellite uplink, radio determination and ultra-wide band applications. The antenna has been fabricated and efficaciously tested using E5071C network analyser and anechoic chamber. It has been perceived that the practical results match with the simulated results.