The Design Study of the Wide Bandwidth and High Gain RFID Microstrip Patch Antenna

A design of a wide bandwidth high gain micro strip antenna for RFID is proposed, in which the design of the wide bandwidth is achieved by the dual-band operation, which is realized by loading two symmetric cut down squares at the corner of the ordinary rectangular patch antenna, and changing the surface current distribution on the patch. Based on this, A 4-element array antenna is designed by selecting an appropriate space between every two elements, adopt coaxial probe and the parallel feed network comprised of T-type power distributors. Simulated and optimized by using the software of High Frequency Structure Simulator(HFSS), the simulation results show that the relative impedance bandwidth is about 18.8% for the antenna element and 19.5% for the antenna array, and the gain is about 14.2dB. the method of designing has a good expansibility for particular feeding and the muti-layers micro strip patch antenna.