It is very important to know the heat field properties of radiating dipole antenna for intracavitory microwave hyperthermia. In this paper, a water-cooled two-slot dipole, radiating in a biological tissue, is analyzed with a theoretical electromagnetic model by using superimposition principle. The SAR (specific absorption rate) and temperature distributions are calculated, taking into account the effect of the water flowing inside the applicator, and compared with the water-cooled one-slot dipole for different slot-slot distances. The computer simulations show that, the SAR and temperature distributions are uniformally improved on the extensions of the effective heating volume and the effective therapeutic volume by suitablely selecting the distance of slot-slot as to λ/4～λ/2 (λ: wave length). The calculated numerical results comform with those of equivalent muscle phantom experiment and clinical engineering practices.%微波辐射器的热场特性对腔道肿瘤热疗有重要实用意义。本文根据电磁场迭加原理，计算了水冷式双缝隙微波偶极子辐射器的热场(比吸收率和温度)分布；分析了热场随两缝隙间距变化的特征关系。仿真计算结果表明，适当选择缝间距离(如等于1/4～1/2波长)，双缝辐射器不仅在径向，尤其在轴向可比单缝具有更为平坦的热场分布，从而可获得更大的有效治疗空间。本文计算结果与相应的等效肌肉体模实验及热疗临床经验相符，将为腔道水冷式微波辐射器的研制设计和临床应用提供参考依据。
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