High-K dielectric constant epoxy material

We have a collection of target assemblies that are used to validate our computational software. A few assemblies consist of rectangular and cylindrical microwave resonant cavities (which are basically implemented as just terminated copper tubes and boxes with sma connectors). We had a somewhat unusual idea to use these same microwave assemblies for low frequency verification by filling these cavities with super-high dielectric constant epoxy (reuse of the same geometries would greatly reduce our computational and physical setup effort). We were wondering if anyone knows it such filling material exist with dielectric constants in the hundreds?

You might contact ATK/Composite Optics (w*w.coi-world.com) and ask them that question.

Good Luck.

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