The invention provides a sample table for inhibiting a quasi-
optical cavity degeneration higher-order mode and a testing method and application thereof. The sample table comprises a
dielectric substrate, the center of the
dielectric substrate is provided with a circular
metal coating layer, and a
microwave matching circuit structure is engraved on the
metal coating layer. The
microwave matching circuit structure comprises two gaps which are symmetrically arranged at two sides of the center of a circle of a circular
metal coating layer and are parallel to a TEM00q mode
electric field direction.The thickness of the
metal coating layer is greater than the
skin depth of working frequency point electromagnetic
waves; the loss tangent value of the
dielectric substrate material is higher than 1e-4. According to the invention, on the premise that the TEM00p mode is not affected, the non-TEM00p mode near the TEM00p mode is not matched, so that the
resonance phenomenon cannot be excited; and thus the energy can be consumed through the high-loss substrate, so that double peaks appearing in the TEM00p mode corresponding to the
frequency spectrum can be improved into symmetrical single peaks;when the quasi-
optical cavity method is used for testing a complex dielectric constant, the test of the Q value corresponding to the TEM00p mode is more real, so that the precision of testing the lossof the material to be tested through the quasi-
optical cavity method is improved.