This paper presents the design and realization of a microwave applicator at 2.45 GHz for the synthesis of gold nanoparticles. The particles are dissolved in N, N-dimethylformamide (DMF). The heating rate is approximately 8 K/s to achieve a short crystallization time. For a proper applicator design it is necessary to know the dielectric properties of DMF. Therefore, the complex permittivity of DMF at 2.45 GHz is measured in a temperature range from 20 °C to 80 °C. The final applicator design is presented together with simulation results for the electric and thermal field distributions. The calculation of the temperature distribution is done with Comsol Multiphysics™ and considers mutual coupling between the electric and thermal field. To avoid overheating, a thermal controller is developed to control microwave power in dependency of the liquid’s temperature. Finally, measurement results for matching and achieved heating rate are presented.

中文翻译：

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一种用于纳米粒子合成的微波施加器的设计

本文介绍了用于合成金纳米粒子的 2.45 GHz 微波施加器的设计和实现。将颗粒溶解在 N, N-二甲基甲酰胺 (DMF) 中。加热速率约为 8 K/s，以实现较短的结晶时间。对于正确的涂抹器设计，有必要了解 DMF 的介电特性。因此，DMF 在 2.45 GHz 的复介电常数是在 20 °C 到 80 °C 的温度范围内测量的。最终的施加器设计与电场和热场分布的仿真结果一起呈现。温度分布的计算是使用 Comsol Multiphysics™ 完成的，并考虑了电场和热场之间的相互耦合。为避免过热，开发了一个热控制器来根据液体温度控制微波功率。最后，给出了匹配和达到的加热速率的测量结果。