Enhancing Axial Ratio Bandwidth of Dual Band Microstrip Patch Antenna for GSM Application

The paper objective is to designed circular polarized microstrip patch antenna and enhancing axial ratio bandwidth with improved impedance bandwidth. An antenna is designed using stacking method. The design of the antenna is achieved using two slots on the main radiating patch and one cross slot on the near field resonating parasitic patch (NFRP). The NFRP patch is positioned below the main radiating patch at some height. The structure is called modified Hilbert shaped antenna. A slots methodology on patches is used for the attainment of wider bandwidth. Improvement of the axial ratio bandwidth of an antenna is achieved by the introduction of NFRP patch. The antenna that has been designed is resonated at frequencies 900 MHz and 1890 MHz, covering two bands i.e. (725-990) MHz & (1800-1920) MHz with a return loss of -25 dB. Impedance bandwidths are obtained 265 MHz and 120 MHz at these frequencies. Furthermore, bands are covered by a 3-dB axial ratio of (800950) MHz and (1720-1920) MHz. The percentage axial ratio bandwidths are obtained 17.14% and 10.98% over the operating bands. An average gain and radiation efficiency is reported 6.7 dBi and 84% for the antenna. The size of the antenna is calculated 0.3600.420 0.0420. In summery the antenna is described as a dual-band, circular polarized with a stable gain and wider axial ratio bandwidth, deemed suitable for GSM (Global System for Mobile Communication) applications.