Abstract: A method of using a resonant cavity for measuring a complex permittivity ? and identifying of a sample (solid or liquid) of microliter volume size includes using a network analyzer to measure over a defined millimeter wave frequency range, a first resonance frequency at a cavity resonance mode, and calculating an unloaded quality factor of an enclosed resonant waveguide cavity of a defined internal dimensions, placing a sample on a surface of a bottom wall of the resonant waveguide cavity and measure a second resonance frequency and calculating a loaded quality factor; determining, a resonance frequency shift ?f=(fs?fo), determining a complex permittivity ? of the sample according to the resonance frequency shift ?f, the loaded quality factor, the unloaded quality factor and the defined internal dimensions; and identifying the sample using a database through the complex permittivity ?.

Abstract: A method, a resonant cavity and a system for measuring a complex permittivity a and identifying of a sample (solid or liquid) of microliter volume size is disclosed. The method including using a network analyzer to measure over a defined millimeter wave frequency range, a first resonance frequency at a cavity resonance mode, and calculating an unloaded quality factor of an enclosed resonant waveguide cavity of a defined internal dimensions, placing a sample on a surface of a bottom wall of the resonant waveguide cavity and measure a second resonance frequency and calculating a loaded quality factor; determining, a resonance frequency shift ?f=(fs?fo), determining a complex permittivity ? of the sample according to the resonance frequency shift ?f, the loaded quality factor, the unloaded quality factor and the defined internal dimensions; and identifying the sample using a database through the complex permittivity ?.