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Attenuation Constant (attenuation + constant)
Selected AbstractsEstimation of backward impedance on low-voltage distribution system using measured resonant currentELECTRICAL ENGINEERING IN JAPAN, Issue 3 2010Toru Miki Abstract Two estimation methods for a backward impedance of a power distribution system are proposed in this paper. According to the first method, the backward impedance is estimated based on information obtained from the frequency response of a transient current flowing into a capacitor connected to a distribution line. The backward impedance is determined from the attenuation constant and the resonant frequency calculated using the capacitance and the impedance of the power distribution system. These parameters can be reliably obtained from a frequency response of the transient current using the least square method. The accuracy of the method strongly depends on the origin on the time axis for Fourier transform. An additional estimate of the time-origin is required for an accurate estimation of the backward impedance. The second method estimates the backward impedance using two transient current waveforms obtained by alternately connecting different capacitors to a distribution line. The backward impedance can be represented as a function of the frequency responses of these currents. Since this method is independent from the time-origin, it is suitable for automatic measurements of the backward impedance. Proposed methods are applicable to the estimation of harmonic currents in distribution systems. In this paper, harmonic currents flowing through a distribution line are calculated based on the estimated backward impedance and on the measured values of voltage harmonics obtained by the instrument developed by the authors. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 28,40, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20900 [source] An analysis of substrate effects on transmission-lines for millimeter-wave CMOS RFIC applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008Jin-Fa Chang Abstract A set of transmission lines (TLs) for millimeter-wave (MMW) CMOS RFIC applications was implemented in a standard 0.18 ,m CMOS technology and then postprocessed by CMOS-compatible inductively-coupled plasma (ICP) etching, which removed the silicon underneath the TLs completely. TL parameters such as characteristic impedance ZC, attenuation constant ,, phase constant ,, effective permittivity ,eff, minimum noise figure (NFmin), parallel capacitance/conductance C/G, and series inductance/resistance L/R, as a function of frequency were extracted. It was found that ,, ,eff, NFmin, C, and G were greatly improved after silicon removal. The state-of-the-art performances of the on-chip TLs-on-air suggest that they are very suitable for application to realize ultralow-noise MMW CMOS RFICs. Besides, the CMOS-compatible backside ICP etching technique is very promising for MMW system-on-a-chip applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 319,324, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23055 [source] Loss inclusion via dyadic Green's function modifications for microstrip structures with complex media: Interfacial exponential field behavior within conductor ,MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2001Clifford M. Krowne Abstract 2-D field behavior within a metal strip is used to correct the dyadic Green's function for a microstrip structure containing complex-layered media so that the attenuation constant can be determined. In the x -direction, the field is built to display exponential dependence. The strip width is explicitly taken into account, along with the metal thickness and conductivity. New Green's function expressions of the structure are found consistent with a full-wave electromagnetic code employing zero thickness extent conductors for the guiding metal. Implications for numerical implementation are covered. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 54,60, 2001. [source] Actively and passively excited sinusoidal microstrip and PCB strip antennas operating at K and millimeter-wave bandsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2008A. O. Salman Abstract Actively and passively excited sinusoidal wire structure is applied to the PCB strip and microstrip structures successfully at K and millimeter-wave frequency bands. Antenna dimensions are reduced till the half value, and more rigid structure is also obtained than the sinusoidal wire antennas by this way. Actively excited PCB sinusoidal antennas are investigated at these high frequencies and passively excited ones are introduced in the literature for the first time in this study. Transversely polarized broadside radiation is obtained for both types of antenna. The measured field patterns are compared with the calculated and simulated ones. The calculated patterns, phase velocity, and attenuation constants of investigated antennas are calculated by a written MATLAB code based the analytical approach. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1302,1308, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23347 [source] | ||||||||||