Estimation of substrate materials for microwave application

Summary form only given. The wide application of both microwave integrated circuits and planar microwave antennas needs the use of appropriate methods for estimation of the main substrate parameter-the complex permittivity. Usually, the data submitted by manufacturer are specified for definite conditions (e.g. frequency, operation temperature, orientation of the applied electromagnetic field etc.). Therefore, additional data concerning the substrate behavior seem to be useful for a number of application. We describe some methods approved for estimation of different substrate materials for microwave application. A high quality cylindrical resonator operated at the TE₀₁₁ mode is used for estimation of foam materials, thin layers, and substrates with low permittivity on the based on the perturbation technique. With addition of the full wave consideration the resonator can be used for measurement of the substrates with higher permittivity and thickness not satisfying the perturbation technique limitations