A 1?2 array circularly polarised Microstrip antenna with a high Gain for RFID applications

Radio Frequency Identification, RFID, known to most, is a wireless technology used for identifying as well as tracking a tag attached to an object. This work deals with the design construction of a compact Microstrip antenna which has a high Gain along with a sufficient Return Loss (S₁₁) and Impedance bandwidth that will work for 2.4 GHz ISM band RFID Applications. The antenna has been designed and simulated on a Fire Resistant FR4 Epoxy substrate. The antenna is an array of 1×2 elements, has overall dimensions of 120 × 73 × 1.5 mm³ and has a Microstrip line feed matched to 50Ω. The impedance bandwidth achieved by the final design is about 100 MHz at the 2.4 GHz ISM band and has an S11 about -16.10 dB. The Gain achieved by the antenna is around 7.50 dB. The final design has a very good Circular Polarisation(CP) with an Axial Ratio of 0.8 dB and an Axial Ratio bandwidth of 47 MHz. The antenna is highly directional with beam width of 60°. The antenna has been designed using Ansoft High Frequency Simulation Software (HFSS).