Design of tri-band antenna for WiMAX

A microstrip antenna with triple bands is designed for Worldwide Interoperability for Microwave Access. The antenna uses microstrip feeds through four semicircular rings; and a semicircular patch to produce two operating frequencies. After that we used a rectangular patch with grooves to excite the third frequency. Meanwhile the method of opening a rectangular groove on the ground improves the bandwidth of the antenna. The antenna was simulated using high frequency simulation software. The return loss of the antenna in three frequency bands is less than -10dB; and good far field radiation patterns have been obtained. The tested results show that the antenna can meet the design requirements.