Michael D. Janezic

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Time-domain free-field measurements comprised the dielectric properties of several common building materials using dual-ridged guide antennas and 1 m × 1 m samples placed on an optical table covered with an absorber. The samples are polycarbonate, gypsum, plywood, a brick wall, and a concrete wall. Time gating and deconvolution are used to isolate a(More)
In this paper, a full-wave method for the electromagnetic analysis of dielectric-loaded cylindrical and coaxial waveguides and cavities is developed. For this purpose, a new four-port ring network is proposed, and the mode-matching method is applied to calculate the generalized admittance matrix of this new structure. A number of analyses on(More)
We have developed a broad-band technique for measuring the relative permittivity of lowthin films using microstrip transmission-line measurements. From measurements of the complex microstrip propagation constant and the characteristic impedance, we determined the relative permittivity of thin films incorporated in microstrip lines. We present measurement(More)
Building materials are often incorporated into complex, multilayer macrostructures that are simply not amenable to measurements using coax or waveguide sample holders. In response to this, we developed an ultra-wideband (UWB) free-field measurement system. This measurement system uses a ground-plane-based system and two TEM half-horn antennas to transmit(More)
In this paper we develop dielectric polarization evolution equations, and the resulting frequency-domain expressions, and relationships for the resulting frequency dependent relaxation times. The model is based on a previously developed equation that was derived using statistical-mechanical theory. We extract relaxation times from dielectric data and give(More)
We discuss the characterization of phantom materials that simulate the electromagnetic characteristics of various human tissues from 100 Hz to 10 MHz, and over a temperature range of 15 C to 40 C. The materials studied were: 1) a solution of potassium chloride in water, 2) a solution of propylene carbonate, ethylene carbonate, and salts, 3) a semi-solid(More)
We investigate the feasibility of using dielectric spectra to classify hazardous and nonhazardous liquids. The dielectric spectra of several liquids was obtained with a shielded-open coaxial fixture, and we present a new full-wave model for calculating the complex permittivity of liquids using this fixture. Using the measured complex permittivity for each(More)