The Gordon coupler was introduced for use in EPR experiments at liquid helium temperatures. It provides an evanescent wave incident on the iris of a microwave resonator. Match of power incident on the coupler to the resonator is obtained by variation of the amplitude of an evanescent wave that arises from displacement of a dielectric wedge in a tapered waveguide. Reduced microphonics from helium bubbling was reported. The Gordon coupler was subsequently extended from cavity resonators to loop-gap resonators, initially at helium temperatures but later for aqueous samples. Plastics with low dielectric constants, usually Teflon, were used. Here, we extend the Gordon coupler for application in X-band five-loop–four-gap resonators using fused quartz, sapphire, or rutile dielectrics, noting that the size of the coupler can then be commensurate with dimensions of dielectric loop-gap resonators as well as dielectric tube resonators. Finite-element modeling of electromagnetic fields has been carried out, and use of a capacitive iris that interfaces with the Gordon coupler reduces pulling of the resonant frequency when matching the resonator.

Gordon 耦合器被引入用于液氦温度下的 EPR 实验。它提供入射到微波谐振器虹膜上的倏逝波。耦合器上入射功率与谐振器的匹配是通过渐逝波振幅的变化来获得的，渐逝波是由锥形波导中电介质楔形物的位移引起的。据报道，氦鼓泡可降低颤噪效应。戈登耦合器随后从空腔谐振器扩展到环隙谐振器，最初在氦温度下，但后来用于水样。使用低介电常数塑料，通常是聚四氟乙烯。在这里，我们将戈登耦合器扩展到使用熔融石英、蓝宝石或金红石电介质的 X 波段五环四间隙谐振器中，注意到耦合器的尺寸可以与电介质环间隙谐振器的尺寸相称以及介质管谐振器。已经进行了电磁场的有限元建模，并且使用与戈登耦合器接口的电容光圈减少了匹配谐振器时对谐振频率的牵引。