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 × 0.055λ_0, 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.

中文翻译：

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具有电容耦合匹配网络的微带环形天线的建模与分析

在本文中，利用等效电路模型和腔模型对具有电容耦合匹配网络的微带环形天线进行建模和分析，该结构简单，准确。所提出的方法不仅证明了工程设计背后的物理原理，而且将是微带环形天线设计的良好指南。设计了工作在UHF RFID频段（902-928 MHz）的原型。所提出的天线的整体尺寸是大约0.5 λ ₀  ×0.5 λ ₀  ×0.055 λ _0，并且实现了增益比5分贝较大轴向比小于3分贝小。测得的结果与模拟的对应物非常吻合，只是频率偏移很小。