Study and Investigations on Various Microstrip Patch Antennas for Wireless Applications

Abstract

Wireless communications has been developed widely and rapidly in the modern world especially during the last two decades. The future development of the personal communication devices will aim to provide image, speech and data communications at any time, and anywhere around the world. This indicates that the future communication terminal antennas must meet the requirements of multi-band or wideband operations to sufficiently cover the possible operating bands. However, the difficulty of antenna design increases when the number of operating frequency bands increases within a single antenna. The aim is to study and design various rectangular microstrip patch antennas for wireless communication systems and study the effect of various antenna parameters like patch length (L), patch width (W), substrate relative dielectric constant, substrate thickness etc. Here, coaxial feed and microstrip line feed methods have been used to excite the patch antenna. The single band rectangular patch antennas have been designed for the frequency 5.2 GHz using microstrip line feeding and coaxial feeding technique. The design is successfully simulated using CST Microwave Studio software. In microstrip line feed antenna, the return loss is -47dB & bandwidth is 196 GHz. In coaxial feed antenna the return loss is -35 dB & bandwidth is 160 GHz. Three dual band antennas using DGS structure and one dual band antenna using dual patch has been designed. The designs have been successfully simulated using CST Microwave Studio Software. Dual band defected ground microstrip patch antenna for WLAN/WiMax and satellite application, the return loss for 5.5 GHz band and 6-7 GHz band is -27.26 dB and -20.77 dB respectively, bandwidth for 5.5 GHz band and 6-7 GHz band is 1.24 GHz (4.6053 GHz – 5.8481 GHz) and 1.04 GHz (6.124GHz – 7.16 GHz) respectively. Dual band microstrip patch antenna for GSM and WiMax application, the return loss for GSM band and WiMax band is -20.8 dB and -30.98 dB respectively, bandwidth for GSM band and WiMax band is 366 MHz (1600 MHz – 1900 MHz) and 583 MHz (3350 MHz – 3933 MHz) respectively. Dual band microstrip patch antenna, using two slits and defected ground structure, the return loss for 3.5 GHz band and 5.8 GHz band is -41.71 dB and -20.67 dB respectively, bandwidth for 3.5 GHz band and 5.8 GHz band is 495 MHz (3.403 GHz – 3.901 GHz) and 260 MHz (5.569 GHz – 5.830 GHz) respectively.