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This paper presents a rigorous analytic approach for the prediction of the in-band and out-of-band intermodulation distortion of fifth-order memoryless nonlinear RF circuits/systems modeled using a Taylor series and driven by phase-aligned or random phase multitone excitation. Nonlinear distortion figures-of-merit such as intermodulation ratio (IMR), adjacent channel power ratio, co-channel power ratio, and noise-to-power ratio, as well as the output power density can be straightforward computed using newly developed closed-form expressions. Simulation results of output power density obtained using the developed expressions for an -band commercial amplifier demonstrates the time efficiency and robustness of the proposed approach when compared to averaged data obtained using numerical simulators such as Agilent ADS. The comparison of the computed nonlinearity figures-of-merit with those previously published shows the importance of considering the fifth order when modeling nonlinear RF circuits/systems. The proposed analytical approach explicitly highlights the dependency of the normalized figures-of-merit relative to the standard two-tone IMR (IMR 2 ) to the input power and to the coefficients of the Taylor model contrary to third-order-based approaches.

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In this paper, a new method-of-moments-based approach is proposed for the analysis of non-uniform lossy substrate integrated waveguides (SIW) transmission lines. The approach incorporates Chebyshev expansion in the frequency domain to compute the scattering parameter matrix of the line. To validate the proposed approach of non-uniform structures are analyzed where two of them have been fabricated and measured. The analytical and measured S parameters were compared to those obtained through electromagnetic finite elementbased simulations. The good match observed between the two sets of results for a relatively reasonable number of basis functions confirms the accuracy and the fast convergence of the proposed approach. This makes it the most suitable for integration into computer-aided design tools.

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In this article, we suggest a new set of basis functions that are based on Zernike polynomials for the behavioral modeling of radio frequency power amplifiers (PAs). The modeling of highly nonlinear PAs exhibits numerical instability that degrades the accuracy of the model parameters and predistorter modeling efficiency. Simulation results show that the proposed polynomial model is more suitable to resolve the numerical instability problem and proves to have greater accuracy with reduced complexity. A Doherty PA driven by a multicarrier wideband code division multiple access signal was used for validation; and, the obtained results show that the new model exhibits superior numerical stability as the nonlinearity order and memory depth of the model increase. V C 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 00:000-000, 2012.

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Microwave imaging for breast cancer detection is based on the contrast in the electrical properties of healthy fatty breast tissues. This paper presents an industrial, scientific and medical (ISM) bands comparative study of five microstrip patch antennas for microwave imaging at a frequency of 2.45 GHz. The choice of one antenna is made for an antenna array composed of 8 antennas for a microwave breast imaging system. Each antenna element is arranged in a circular configuration so that it can be directly faced to the breast phantom for better tumor detection. This choice is made by putting each antenna alone on the Breast skin to study the electric field, magnetic fields and current density in the healthy tissue of the breast phantom designed and simulated in Ansoft High Frequency Simulation Software (HFSS).