Microwave dielectrics with unstable electronic spectrum

High dielectric constant microwave dielectrics are basic materials for dielectric resonators and filters, as well as for microwave substrates, dielectric waveguides, etc. These dielectrics are possible to improve only through the understanding of physical nature of their polarization. High value E without significant absorption electrical energy at the frequency range of 10…100 GHz can be realized only at the expense of quick-response mechanisms of polarization. The theoretical possibility to obtain thermal stable dielectrics with high εmw but at very low temperatures exists. One previously unknown possibility to combine high permittivity, low loss factor with thermal stability is discussed. It is based on fast-response electronic-phonon mechanism of polarization in dielectrics with the unstable electronic spectrum (like in the quasi one-dimensional crystals of TTF-TCNQ type).