Vol 18, No 4 (2015)

Waveguide diode frequency tripler in the range of 75 to 110 GHz calculation and design method, based on using HFSS and Designer programs, combining electrodynamic waveguide structures and nonlinear characteristics analysis, was proposed. Comparison of frequency tripler rated and measured parameters is given.

The mathematical modeling of propagation of electromagnetic waves in waveguiding structures based on carbon nanotube - graphene at terahertz and infrared frequency ranges by solving the Maxwell’s equations with electrodynamic boundary conditions, complemented by the constitutive laws for carbon nanotubes and the grapheme, was done. Using method of autonomous blocks with Floquet channels the electrodynamic calculation of coefficients of delay and extinction of the fundamental mode in waveguiding structures based on carbon nanotube - graphene carbon nanotube with various radius ( r = 25-2 nm) and the distance between carbon nanotube and graphene) depending on the frequency were obtained for different values of chemical potential (the external electric field intensity) at terahertz and near infrared frequency ranges.

A measurement procedure, which includes investigation of the illuminating field with a probe being moved around the work area, is analyzed. This field is represented by a convergent cluster of plane waves, the spatial spectrum of which is used at the stage of pattern reconstruction. On examples of two-dimensional scalar tasks (measuring in the plane and under condition that polarization antenna and illuminating field are the same), very interesting reliefs of fields formed by plane waves cluster, which approximates a spherical wave from a relatively close source, are shown inside and outside the working area. Methodical accuracy of the pattern retrieval with using an isotropic probe and a probe with a cardioid pattern is compared. In the first embodiment, strengthening of the ill-posed problem of an appropriate algebraic equations system leads to a growth of oscillations of approximating field and less accurate retrieval of the antenna pattern.

The effect arising in discrete time at interaction of self-oscillations with higher harmonics of the main frequency is described. It is shown that it is similar to effect of capture of the frequency (synchronization) of self-oscillations by an external harmonic signal. As the discrete oscillator formally is autonomous system, the effect is classified as self-capture of frequency or self-synchronization. Self-capture is analysed by method of slow-changing amplitudes. It is specified that via the mechanism of self-synchronization the binding of frequency of discrete self-oscillations to sampling frequency is carried out.

Possibilities of optimization of routes of flight of pilotless aircrafts for the increase of exactness of position-fix of surface sources of радиоизлучения on the estimations of angular coordinates from their sides are investigated. The rules of choice of points of direction-finding of signals are found on the trajectory of motion of single pilotless aircraft and course corners of two synchronously flying carriers of direction receivers-fingers from composition of the angle system, at that a minimum of dispersion of measurement of the coordinates of objects is arrived at.

It is shown that the Malus law based on the principles of classical electrodynamics not completely takes into account all effects which can occur at passage of a linearly polarized light through the analyzer. On the basis of the quantum representations about the nature of light the form of Malus law which is taking into account transfer of a part of a photon impulse to particle on which occurs reradiation of light forward is found. Calculations are carried out within the framework of the perturbations theory with use of the Feynman diagram technics.