The invention belongs to the field of electromagnetic parameter testing for
microwave and
millimeter-wave materials, and relates to an open coaxial
resonator, in particular to a novel method for testing the
microwave complex
permittivity of high-loss liquid and
powder materials. According to the method, the
resonance frequency and quality factor at the front and the back of a tested
microwave material are loaded through the open coaxial
resonator, a piece of
wine glass furniture is arranged on the open coaxial
resonator, the thickness of a sample is loaded, and therefore the complex
permittivity of the sample to be tested is calculated. A testing
system built according to the method comprises the open coaxial resonator, probes,
converters from an SMA to another coaxial connector, cables, a vector network analyzer and the
wine glass furniture, wherein the six parts are connected to form the
system; the length of the part, extending deep into the resonator, of each probe is adjusted through a
coupling adjuster; the quality factor of the
system is made maximal at a
resonance frequency point, and the
resonance frequency f0 and quality factor Q0 of the system at the time are recorded; the material to be tested is placed into the
wine glass furniture, flatness of the upper surface of the sample is guaranteed, the thickness d of the sample is measured, and the resonance frequency f1 and quality factor Q1 of the system after the sample is loaded are recorded. The complex
permittivity of the material to be tested is calculated according to the parameters obtained previously.