We describe design of two-polarization imaging array of 7 antenna-coupled TES-bolometers. The fabrication procedure
involves both electron beam lithography and convenient optical lithography resulting in submicron definition of TES
absorber films (down to ~ 0.2 μm) integrated within planar submm-wave antenna. Concept of matching optics between
the long-focus optical telescope and lens-antenna TES bolometer array is described. Two-mirror short-focusing beam
concentrator in combination with image rotator provides signal coupling to immersion lenses of the array. Each TES
bolometer is coupled via microstrip transmission line to only one polarization of two-polarization crossed double-slot
lens-antenna. Design of cryogenic 0.3-K system accommodating the matching optics is presented. We describe
multiplexing readout scheme, which combines tomography, rotational scanning of the image and frequency domain
division methods that drastically reduce the amount of wiring and substantially increase the final image resolution,
especially for low-dimension arrays.
Successful preparation of the Ce-Zr-Al oxide thin films and glassy products by a newly developed organic-free modification of the sol-gel technique is reported. The structural composition and some properties of the samples obtained were investigated by TEM, XRD, FTIR, ESR, UV-Vis, PL and XPS. The optical investigation of the obtained films together with ESR data indicate the appearance of the bulk Ce<sup>3+</sup>-defects (g⊥ = 1.962-1.967, g// = 1.938-1.940, assigned to 4f<sup>1</sup> state, with concentration ~2•1018spin/g). The significant PL intensity rising at elevated temperature was related to spontaneous increasing of Ce<sup>3+</sup> concentration in sol-gel samples under thermal dehydration. Also, an unexpected formation of intra-band gap states during thermal treatment of xerogels was manifested in UV-Vis spectra. This intra-band-gap states was attributed to the oxygen related defects that contribute to PL signal.
Binary oxide solid products and glasses in the ZrO<sub>2</sub>-GeO<sub>2</sub> system with the Ge:Zr molar ratio ranged from 1:1 to 3:1 were synthesized from inorganic precursors in aqueous medium by ammonia stimulated hydrolysis and coprecipitation. The latter were formed due to reaction of Zr(IV)+Ge(IV) solution with precipitating agent. The precipitated xerogels covered a color spectrum from white to red, and the color was more intense with increase of GeO<sub>2</sub> content in the binary ZrO<sub>2</sub>-GeO<sub>2</sub> composition. DTA, XRD, IR, and XPS were used for examination of crystalline structure and phase transformations in the coprecipitated amorphous xerogels and thermally treated ZrO<sub>2</sub>-GeO<sub>2</sub> products. In samples with excess of germania in the binary ZrO<sub>2</sub>-GeO<sub>2</sub> system both tetrahedral and octahedral coordination of Ge occur, resulting in different crystallization behaviors. In line with the stable ZrGe0<sub>4</sub> phase with scheelite structure we have established an appearance of new crystalline phase (called X-phase) for thermally treated (1000°C) samples with Ge:Zr = 2:1 and 3:1 rather than the hexagonal GeO<sub>2</sub> phase.
It was originally analytically solved the problem of field distribution of a narrow-directed MM-wave beam behind obstacle. Experiments proved anticipated field levels that are 40 dB higher than the levels of omni-directed decimeter (DM) radiation. It was proposed and verified in series of measurements the model of forming of interference structure of MMW beam field in a shadow of vegetation, versus vertical receiver movement. Taking into account MMW beam peculiarities, it was demonstrated the advantages of frequency re-use increasing efficiency in digital cellular network in comparison with existing DM systems, in application to mobile telecommunications and fixed wireless access.