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High permittivity with small dielectric losses in frequency range of 1…100 GHz can be realized only due to quick-response mechanisms of polarization. In the report some new assumptions as to thermal stability realization is proposed. Firstly, microwave dielectrics should be based on “hard” paraelectrics, which structure resists to polar phases formation. Secondly, high thermal stability is caused...
The analogy between charge carriers scattering in disordered spin structure of conductors and in polar disordered structure of dielectrics is noted and confirmed. When moving in spin-disordered structure, electrons scattering increases and becomes very large in case of opposite-spin structure of anti-ferromagnetics. On contrary, in regular parallel-spin structure of ferromagnetic resistivity decreases...
With a purpose of microwave equipment frequency range enlargement, and in order to improve quality factor of frequency-selective devices, thin dielectric resonators (DR) are investigated. The principles of microwave filters and phase shifters designs, based on thin dielectric resonators, are presented. Some new constructions of such devices are elaborated. Results of theoretical and experimental studies...
Electronic sensors and controlling devices widely use specific materials, in which electrical resistance can be changed many times under the influence of external factors: temperature, pressure, electrical field, moisture and even smell. In the report, a principal mechanism is examined: how electrical polarization can affect the conductivity in different crystals. Understanding of physical nature...
High dielectric constant microwave dielectrics are basic materials for dielectric resonators, filters, microwave substrates, etc. These dielectrics can be improved through understanding of their polarization physical nature. High value of permittivity with small dielectric losses in frequency range of 1…100 GHz can be realized only due to quick-response mechanisms of polarization. In the report, firstly,...
In this review some gigantic effects, discovered not long ago and very important for application in electronics, are characterized. These descriptions are taken from our recently published textbooks: they cover field of electronic materials science and intended for students, specializing in electronics. These textbooks are based on authors' many years experience in lecturing in field of materials...
A novel conception of peizoelectricity physical nature is proposed and dicussed. Some peculiarities of piezoelectric crystals (so cold polar-neutral crystals) would be described by a concept of their intrinsic (latent) polarity. Its components show a critical law P ∼ (θ − T)n and vanish at the phase transition temperature θ. The critical parameter equals to n = 1 if all components of intrinsic polarity...
Electric polarization is the separation of electrical charges that is accompanied by the deformation of the crystal (strain). Therefore polarization is not just electrical but the electro-mechanical phenomenon. In the case of the piezoelectric effect the external mechanical stress which is applied to the crystal does not produce, but only highlights the existing internal polarity of the crystal (hidden...
Many physical mechanisms are known in dielectrics that lead to the energy loss, but in each frequency range one dominating mechanism of loss exists. Contemporary information technologies start to use gigahertz frequency domain where dielectrics with high permittivity ε are the most needed. That is why this report is devoted to the nature of losses in the microwave dielectrics. Experimental and theoretical...
Electrostriction can be used to control low loss and highly tunable microwave dielectric devices (filters and phase shifters). Dielectric or metallic parts of such a device should have the dirigible air gap between them. For non-hysteresis control these devices use relaxor ferroelectric with large electrostriction. However, electro-mechanic way of control might have a restriction in the speed of operation...
The method of dielectric spectroscopy is described. The method is used to study micro — and macroscopic mechanisms of polarization, nature of phase transitions in materials of different aggregate states. Methods for dielectric parameters measurement at microwaves are classified.
The electromechanical tune method for microwave filters based on coplanar lines are proposed. The simulation of the proposed filter structure was made by finite differences method in the time domain. This method allows tuning for resonance frequency about 80 percents with the air gap between the substrate and the signal electrode width about 50 μm. The proposed method can be realized with MEMS technology...
Low loss and highly tuneable microwave filters controlled by piezoelectric actuator are discussed. Dielectric or metallic parts of device should have the piezo-dirigible air gap between them. The most important for these devices is to use non-hysteresis relaxor ferroelectric ceramics with large electrostriction. Electromechanic way of control has restriction in the speed of operation, and this problem...
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