Modeling and analysis of microstrip annular ring antenna with capacitive coupling matching network

Abstract

In this manuscript, microstrip annular ring antenna with capacitive coupling matching network is modeled and analyzed with equivalent circuit model and cavity model, which is simple and accurate for this structure. The proposed approach not only demonstrates physics lying behind the engineering design but also will be a good guideline for the microstrip annular ring antenna design. A prototype working UHF RFID band (902‐928 MHz) is designed. Overall dimension of the proposed antenna is about 0.5λ0 × 0.5λ0 × 0.055λ0, and the realized gain is larger than 5 dB with axial ratio is smaller than 3 dB. The measured results agree well with simulated counterparts except slightly frequency shift.