以牙根分层生物组织为例，采用近似模型，导出了单振子辐射器在圆柱状分层生物介质中的近场公式．通过数值计算，作出了电场分布的曲线，进一步分析比较了各层组织中场强的相对大小，从理论上探讨了微波治疗牙根尖周病的原理，理论分析结果与临床实践相符． Taking the root root stratified biological tissue as an example, an approximate model was used to derive the near-field formula of a monovibrator radiator in a cylindrical stratified biological medium. Through numerical calculations, the curve of electric field distribution was made, and the relative magnitude of the field strength in each layer of tissue was further analyzed and compared. The principle of microwave treatment of periapical periodontitis was theoretically discussed. The theoretical analysis results were consistent with clinical practice.