NEAR – FIELD COHERENT EFFECTS AT THERMAL MICROWAVE RADIATION RECEIVING ON COUPLED LINEAR WIRE ANTENNAS

Y. N. Barabanenkov¹,  M. Yu. Barabanenkov², V. A. Cherepenin¹

¹ V.A. Kotelnikov Institute of Radioengineering and Electronics of RAS, Moscow

² Institute of Microelectronics Technology of  RAS, Chernogolovka

 Received December 4, 2011

 Abstract. We apply to study coupled receiving antennas a theory of electromagnetic wave multiple scattering by ensemble of dielectric and conductive bodies, with describing the excited currents inside bodies in terms of electric field tensor T-scattering operator. A system of equations for currents on surfaces of coupled perfectly conductive receiving antennas is written with the aid of a single antenna surface T-scattering operator. This system  is resolved for the case of coupled linear wire receiving antennas in the form of thin vibrator-dipoles when asymptotic method of “big logarithm“ leads to separable wire T-scattering operator of single tuned vibrator-dipole. The separability simplifies analytic evaluating the local total currents on two (and more) coupled receiving antennas and get a dimensionless coupling factor. Our final aim consists in using the obtained analytic solution to study near field coherent effects caused by thermal microwave radiation incident electric field distribution along single or two coupled receiving vibrator-dipole antennas placed at a heated biological object boundary surface and tuned to half wavelength in the object. In the case of equilibrium thermal radiation we meet a generalized Nyquist formula for currents’ fluctuations excited on coupled receiving vibrator-dipole antennas, with accounting the auto-correlation and cross-correlation functions of random electric field inside each antenna and on both antennas, respectively. In the case of local volume change of the biological object temperature distribution we reveal in the model framework of random electric dipole source inside object absorption skin slab area the interference-extreme properties for fluctuations of currents excited along antennas depending on relative positions of antennas and random electric dipole source. The reveled extreme properties are used as base to reconstruct the random electric dipole position via scanning the single antenna or two coupled ones along biological object boundary surface.

Key words:  receiving coupled antennas, excited currents, T- scattering operator, thin vibrator antennas, biological object, temperature local variation, thermal radiation, interference receiving fields, scanning local random source.