Are the parameters Q0Ã\x97f0, temperature coefficient of frequency and temperature coefficient of permittivity fundamental material constants?

Microwave characterisation of dielectric materials is vital to implement the material in communication devices and circuits. The microwave characterisation parameters are the dielectric constant, loss tangent, Q₀timesf₀ temperature coefficient of frequency and temperature coefficient of permittivity. From several experiments on different dielectric materials, it has been concluded that the concept of using Q₀timesf₀ and temperature coefficient of frequency, as a material property was wrong since it is not reflecting on a material´s fundamental behaviour. On the other hand, it has been interesting to note that the temperature coefficient of permittivity of a material is a constant irrespective of the measurement technique and hence it is a material parameter. The studies on temperature dependent permittivity will reveal the knack of a material to operate as a frequency stable circuit or device.