A Bandpass Filter Based on Dielectric Layers with a Strip Conductor Subwavelength Grating at Their Interfaces

Doklady Physics - The design of a multilayer bandpass filter has been investigated, in which each of the half-wavelength resonators consists of two dielectric layers with outer strip conductor...     

Photoinduced magnetic superstructure in FeBO3:Ni

Dynamic magnetic structure induced by light in FeBO₃:Ni has been studied magneto-optically. Spatial distribution of ferromagnetic vector has been found to be periodical; ferromagnetic vector oscillations obey the quasi-harmonical law with the wave length λ ～ 100μ; the oscillation amplitude is ～ 10° in basal plane and ～0.08° normally to it, so that the hodograph of the ferromagnetic vector is an ellipse with axes ratio being about 100. The direction of propagation of magnetic wave excitations has been ascertained to be determined by the crystal structure only. An average direction of the ferromagnetic vector is deviated from the wave vector of the oscillations.     

Study of a Composite Consisting of Metal Nanoparticles in a Dielectric Matrix and Multilayer Bandpass Filters Based on It

Doklady Physics - The frequency and concentration dependences of the effective complex permittivity of a composite consisting of silver nanoparticles in a polystyrene dielectric matrix have been...     

Physical principles of the design of electrically controllable microstrip devices

Electrically controllable microstrip microwave devices are investigated in which liquid crystals, high-temperature superconducting films, or varactors are used as active media. It is demonstrated that comparatively large controllable phase shifts can be obtained using resonant liquid crystal or varactor phase shifters; however, in this case, the working frequency band of the devices become significantly narrower. The possibilities of obtaining maximum frequency tuning of filters whose bandwidth in the tuning frequency range remains unchanged or changes by a preset law are demonstrated. Varactor designs of two-channel power dividers with a smoothly varying division coefficient between the channels are considered. An original device protecting from a radio pulse based on a superconducting film in which total pulse reflection is observed when the pulse power exceeds a preset threshold is investigated. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 36–45, September, 2008.     

Study of the fields scattered by a periodic strip structure of thin magnetic films

Components of the fields scattered by a periodic planar strip structure of thin magnetic films possessing a uniaxial magnetic anisotropy in the plane have been calculated using the phenomenological model. Regularities in the dependence of these fields on the design parameters of the structure have been studied. The results obtained agree with the numerical analysis of the micromagnetic model of this structure. It has been shown that, near the edges of strips magnetized orthogonally to the major axis, the components of the scattered field can exceed the external magnetizing field by a few orders of magnitude. This fact makes it possible to design highly efficient magnetoresistive elements on the basis of a strip structure of magnetic films and thin semiconductor films.     

Features of Characteristics of Second-Order Bandpass Filters Based on Half-Wave and Quarter-Wave Microstrip Resonators

Russian Physics Journal - A comparison is made of the characteristics of bandpass filters consisting of two interacting resonators, which are either half-wave or quarter-wave segments of microstrip...     

A three-mode microstrip resonator and a miniature ultra-wideband filter based on it

An original microstrip resonator design with a strip conductor split by a slot at one of its ends is investigated. It is demonstrated that at the optimal slot sizes, when the eigenfrequency of the second oscillation mode hits the center between the first and third oscillation modes, the resonator can work as a thirdorder bandpass filter. The structure formed from only two such resonators electromagnetically coupled by split conductor sections is a miniature six-order wideband filter with high selectivity. The test prototype of the filter with a central passband frequency of ~1.2 GHz and a passband width of ~0.75 GHz fabricated on a substrate ~(45 × 11 × 1) mm³ in size with a permittivity of 80 is characterized by minimum loss in a passband of 0.5 dB. The parametric synthesis of the filter structure was performed using electrodynamic analysis of the 3D model. The measured characteristics of the test prototype agree well with the calculated data.     

Micromagnetic calculation of the equilibrium distribution of magnetic moments in thin films

A new approach has been proposed for determining an equilibrium configuration of magnetic moments in condensed matter in terms of its discrete model. The solution to this problem is reduced to a system of linear inhomogeneous equations with undetermined Lagrange multipliers. The possibility of numerically solving these systems has been shown using a modified power method. The efficiency of the method has been demonstrated for the model of a thin magnetic film with a nonuniform distribution of the uniaxial magnetic anisotropy over the area. The dependence of the coercive force on the uniaxial anisotropy of nanocrystallites, their exchange interaction, and other parameters of samples has been investigated.     

Theoretical Study of the Frequency Multiplier Based on Irregular Quarter-Wavelength Microstrip Resonator with Thin Magnetic Film

Russian Physics Journal - The characteristics of a frequency doubler on a resonant microstrip structure with a thin magnetic film were studied theoretically. The electrodynamic calculation of the...