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Microwave Applications (microwave + application)
Selected AbstractsImproved Dielectric Properties of Bi1.5Zn1.0Nb1.5O7/(111)-Oriented Ba0.6Sr0.4TiO3 Bilayered Films for Tunable Microwave ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2010Lihui Yang Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3 [BZN/BST (111)] bilayered films (,500-nm-thick) have been prepared on Pt/TiOx/SiO2/Si substrates by RF-magnetron sputtering. Experimental results suggested that the BZN layer has played a positive role in improving the dielectric properties of the films. With the increased thickness of BZN, the dielectric loss was significantly lowered, accompanied with a tolerable reduction of tunability. The thickness effect was discussed with a series connection model of multilayered capacitors, and the calculated permittivity was obtained. At 400 kV/cm, moderate tunability of 50.55%, low dielectric loss of 0.0108, and the largest figure of merit of 46.8 can be achieved for BZN (50 nm)/BST(450 nm) bilayered films. [source] Temperature Profiles in a Cylindrical Model Food During Pulsed Microwave HeatingJOURNAL OF FOOD SCIENCE, Issue 7 2001H.W. Yang ABSTRACT: Cylindrical 2%-agar gel samples were heated by pulsed and continuous microwave applications. The total microwave application time of 3 min was maintained for all experiments. Sample temperature was measured at various depths along the radial dimension to experimentally determine the internal temperature profile as a function of heating time. A local hot spot was observed at the center portion of the sample during the continuous microwave application. This hot spot was less significant during pulsed microwave applications, especially when longer intermittent power-off times were employed. An implicit finite-difference model was used to estimate temperature profiles within the sample during microwave heating. The estimated temperature profiles matched the experimental values well. [source] EM design of broadband RF multiport toggle switchesINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2004W. Simon Abstract Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329,337, 2004. [source] Temperature Profiles in a Cylindrical Model Food During Pulsed Microwave HeatingJOURNAL OF FOOD SCIENCE, Issue 7 2001H.W. Yang ABSTRACT: Cylindrical 2%-agar gel samples were heated by pulsed and continuous microwave applications. The total microwave application time of 3 min was maintained for all experiments. Sample temperature was measured at various depths along the radial dimension to experimentally determine the internal temperature profile as a function of heating time. A local hot spot was observed at the center portion of the sample during the continuous microwave application. This hot spot was less significant during pulsed microwave applications, especially when longer intermittent power-off times were employed. An implicit finite-difference model was used to estimate temperature profiles within the sample during microwave heating. The estimated temperature profiles matched the experimental values well. [source] Barium Holmium Zirconate, A New Complex Perovskite Oxide: I, Synthesis, Characterization, and Potential Use as a Substrate for High-Critical-Temperature SuperconductorsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2002Rajan Jose Barium holmium zirconate, a new complex perovskite ceramic oxide, has been synthesized through liquid-phase sintering for the first time. The conventional solid-state reaction method using constituent oxides and carbonates was found to be inadequate for the synthesis of Ba2HoZrO5.5 material. During high-temperature annealing, the development of stable BaZrO3 and BaHoO2.5 phases prevented the formation of Ba2HoZrO5.5 as a single-phase material, even at 1650°C. However, an addition of a small amount of CuO (1 wt%) in the reaction mixture has resulted in the formation of an ordered complex perovskite Ba2HoZrO5.5 phase during the heating process. The structure of Ba2HoZrO5.5 was studied by X-ray diffraction and found to have a cubic perovskite structure with a lattice constant of a= 8.482 Å. Dielectric constant and loss factor values of Ba2HoZrO5.5 are also in the range suitable for use as a substrate for microwave applications. The X-ray diffraction and resistivity measurements have shown that there is no detectable chemical reaction in YBa2Cu3O7,,,Ba2HoZrO5.5 and Bi(2212),Ba2HoZrO5.5 composites, even under extreme processing conditions. Dip-coated and melt-textured YBa2Cu3O7,, and Bi(2212) thick films developed on polycrystalline Ba2HoZrO5.5 gave zero-resistivity transition temperatures of Tc(0) = 92 and 85 K, respectively. [source] High-performance integrated passive technology by advanced SI-GaAs-based fabrication for RF and microwave applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2010Cong Wang Abstract In this letter, an advanced SI-GaAs-based manufacturing process is presented for creating high quality, cost effective, and compact size integrated passive devices. Through this advanced process, accurate thin film resistors, high Q spiral inductors, and high yield/breakdown voltage metal-insulator-metal capacitors can be successfully realized. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 618,623, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25018 [source] LTCC broadband deep embedded interconnects (DEI) with application for embedded bandpass filterMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2003J. J. Yu Abstract Careful design of via transitions intended for use in practical microwave applications is needed to realize the advantages of low-temperature co-fired ceramic (LTCC), such as highly integrated buried passive circuits. Grounded coplanar waveguide (GCPW) to asymmetrical stripline vertical interconnects is optimized for thick LTCC substrate. The focus is to develop a vertical transition through thick substrate supporting deep embedded interconnects (DEI). The measured results demonstrate vertical transitions with good performance up to 20 GHz. Embedded LTCC bandpass filter with such vertical transition has been demonstrated with an insertion loss of 2.2 dB and return loss better than ,20 dB at 16.2 GHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 179,181, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11007 [source] YIG thin films for magneto-optical and microwave applicationsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004T. Boudiar Abstract Thin films of Yttrium Iron Garnet (YIG) are grown by radio frequency magnetron non reactive sputtering system on quartz and Gadolinium Gallium Garnet (GGG) for optical applications or alumina substrates for microwave applications. A post deposition annealing is needed to obtain the crystallization of YIG films and the magnetic properties which are correlated with the magneto-optical properties. Their crystallographic, morphologic and magnetic properties are explored. The variation of Faraday rotation is studied versus the wavelength. For both optical substrates, quartz and GGG, results are comparable with the literature for bulk material. A microwave isolator was realized with YIG thin film on alumina substrate in a coplanar configuration. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||