Uniform field (UF) resonators create a region-of-interest, where the sample volume receives a homogeneous microwave magnetic field ($$B_1$$B1) excitation. However, as the region-of-interest is increased, resonator efficiency is reduced. In this work, a new class of uniform field resonators is introduced: the uniform field re-entrant cylindrical TE$$_{\text {01U}}$$01U cavity. Here, a UF cylindrical TE$$_{\text {01U}}$$01U cavity is designed with re-entrant fins to increase the overall resonator efficiency to match the resonator efficiency maximum of a typical cylindrical TE$$_{011}$$011 cavity. The new UF re-entrant cylindrical TE$$_{\text {01U}}$$01U cavity is designed for Q-band (34 GHz) and is calculated to have the same electron paramagnetic resonance (EPR) signal intensity as a TE$$_{011}$$011 cavity, a 60% increase in average resonator efficiency $$\Lambda _\mathrm{ave}$$Λave over the sample, and has a $$B_1$$B1 profile that is 79.8% uniform over the entire sample volume (98% uniform over the region-of-interest). A new H-type T-junction waveguide coupler with inductive obstacles is introduced that increases the dynamic range of a movable short coupler while reducing the frequency shift by 43% during over-coupling. The resonator assembly is fabricated and tested both on the bench and with EPR experiments. This resonator provides a template to improve EPR spectroscopy for pulse experiments at high frequencies.

中文翻译：

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均匀场重入圆柱 TE $$_{01\text {U}}$$ 01 U 腔，用于 Q 波段脉冲电子顺磁共振光谱

均匀场 (UF) 谐振器创建一个感兴趣的区域，其中样品体积接收均匀的微波磁场 ($$B_1$$B1) 激发。然而，随着感兴趣区域的增加，谐振器效率降低。在这项工作中，引入了一类新的均匀场谐振器：均匀场重入圆柱形 TE$$_{\text {01U}}$$01U 腔。在这里，超滤圆柱形 TE$$_{\text {01U}}$$01U 腔设计有凹入翅片，以提高整体谐振器效率，以匹配典型圆柱形 TE$$_{011} $011 腔。新的超滤重入圆柱形 TE$$_{\text {01U}}$$01U 腔专为 Q 波段 (34 GHz) 设计，经计算具有与 TE 相同的电子顺磁共振 (EPR) 信号强度$$_{011}$$011 腔，平均谐振器效率 $$\Lambda _\mathrm{ave}$$Λave 比样本增加了 60%，并且具有 $$B_1$$B1 分布，在整个样本体积上均匀度为 79.8%（98% 均匀度超过感兴趣的区域）。引入了一种带有电感障碍物的新型 H 型 T 结波导耦合器，它增加了可移动短耦合器的动态范围，同时将过耦合期间的频移降低了 43%。谐振器组件是在工作台上和 EPR 实验中制造和测试的。该谐振器为改进高频脉冲实验的 EPR 光谱提供了模板。引入了一种带有电感障碍物的新型 H 型 T 型结波导耦合器，它增加了可移动短耦合器的动态范围，同时将过耦合期间的频移降低了 43%。谐振器组件是在工作台上和 EPR 实验中制造和测试的。该谐振器为改进高频脉冲实验的 EPR 光谱提供了模板。引入了一种带有电感障碍物的新型 H 型 T 型结波导耦合器，它增加了可移动短耦合器的动态范围，同时将过耦合期间的频移降低了 43%。谐振器组件是在工作台上和 EPR 实验中制造和测试的。该谐振器为改进高频脉冲实验的 EPR 光谱提供了模板。