Optimisation of Hakki-Coleman dielectric resonators for precise microwave characterisation of low loss low permittivity dielectrics

In several microwave applications, dielectric materials with small complex permittivity are needed and with precisely known values of εr, and tanδ. In this paper general uncertainty analyses of εr and tanδ measurements carried out using a Hakki-Coleman dielectric resonator are presented for varying parameters of tested dielectrics and uncertainties in the Qo-factor, geometrical factors and losses of the cavity. On the basis of performed analyses conclusions are drawn in respect to optimised construction of a Hakki-Coleman test fixture for accurate microwave characterisation of low loss and low permittivity rod shaped dielectric materials