A method incorporating Bode–Fano integrals is proposed in this paper to evaluate the potential bandwidth of small antennas and provide a particular strategy for bandwidth improvement. The Bode–Fano theory is applied to the equivalent circuit of small microstrip antennas to calculate the maximum achievable return loss-bandwidth. Results of applying this theory to three types of microstrip antennas in mode of propagation with defected ground structure (DGS) and defected microstrip structure (DMS) indicate that creating slots on the microstrip patch or ground structure despite their advantages can decrease the potential bandwidth of the antenna. Fano integrals reveal the invariant relation between maximum achievable return loss-bandwidth and overall volume of the antenna validated using the quality factor (Q factor) analysis.

中文翻译：

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电小型微带天线的回波损耗带宽评估

本文提出了一种结合 Bode-Fano 积分的方法来评估小天线的潜在带宽，并提供一种特定的带宽改进策略。Bode-Fano 理论应用于小微带天线的等效电路，以计算可实现的最大回波损耗带宽。将该理论应用于具有缺陷接地结构 (DGS) 和缺陷微带结构 (DMS) 传播模式的三种类型的微带天线的结果表明，尽管具有优势，但在微带贴片或接地结构上创建缝隙会降低潜在带宽天线。Fano 积分揭示了可实现的最大回波损耗带宽与使用品质因数（Q 因数）分析验证的天线总体积之间的不变关系。