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Item type:Publication, Access status: without files , Theory of irregular impedance waveguides: Generalized method of separation of variablesMaxwell's equations for longitudinally inhomogeneous (irregular) waveguides with impedance walls are equivalently reduced to an infinite set of ordinary differential equations (ODE) by applying transverse expansions. The resulting set of ODE is used for analysis of gyrotron cavities. In particular, the effects of mode conversion and ohmic losses on the operational frequency, quality factor, and field distribution in gyrotron cavities operating in the sub-millimeter range are investigated.Publicationtype: Conference Paper34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Dispersion properties of a magnetoactive plasma-filled waveguide in the vicinity of the upper hybrid frequency. Part IIThe dispersion properties of a magnetoactive plasma-filled waveguide in the vicinity of the upper hybrid frequency ω1 = (ω p2 + ωB2)1/2 (ω1 - δ < ω < ω1) are studied. It is shown that, in this frequency range, the eigenmodes of the plasma-filled waveguide are represented by the families of EH and cyclotron HE modes, the interaction between which is weak everywhere except for the vicinities of certain points in the (ω, k z) plane. The equations describing the behavior of the dispersion curves in these vicinities are derived. It is shown that, as a result of the interaction, the high-frequency branches of EH modes acquire the cutoff frequencies corresponding to the high-order propagating HE modes. It is established that the anisotropic HE+l mode can also interact with cyclotron HE modes. In this case, its dispersion curve enters the lower half-vicinity of the upper hybrid frequency, where it is modified due to the interaction, and then leaves it.Publicationtype: Journal Article37 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Dispersion properties of a magnetoactive plasma-filled waveguide in the vicinity of the upper hybrid frequency. Part IThe dispersion properties of a magnetoactive plasma-filled waveguide in the vicinity of the upper hybrid frequency ω1 = (ωp2 + ωB2)1/2 (ω1 ≤ ω < ω1 + δ) are studied. In this frequency range, the eigenfrequency spectrum and the structure of the waveguide eigenfields are difficult to analyze, because one of the transverse wavenumbers tends to infinity as the upper hybrid frequency is approached. It is shown that this problem can be solved by transforming the dispersion relation into a form independent of this transverse wavenumber. It is also found that the upper hybrid frequency itself can also be a solution to the dispersion relation. The influence of the properties of the magnetoactive plasma-filled waveguide on such solutions is studied. The structure of the fields for modes with frequencies equal to the upper hybrid frequency and an infinitely large absolute value of one of the transverse wavenumbers is analyzed.Publicationtype: Journal Article53 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Clinotron Based Terahertz Imaging System(2014-03); ; ; The clinotron is a vacuum tube that can effective operate in the THz frequency region. A series of clinotron based oscillators have been developed at the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine. In this review, the design and characteristics of these devices are presented. Prospects for the further improvement of clinotron oscillator characteristics are considered. As an example of the application of clinotron oscillators, a 300 GHz beam steering imaging system is presented. Potentialities of the clinotron based imaging systems are considered for future implementations in 3D THz scanners for security and other applications.Publicationtype: Journal Article46