Abstract-The interaction of a helical antenna, mounted on a mobile handset, with a human head phantom is investigated in this paper. Using the Genetic Algorithms (GA) technique combined with the Method of Moments (MoM), an optimization of the antenna structure is achieved regarding the input impedance at the operating frequency. The Finite Difference Time Domain (FDTD) method is then applied to simulate the handset's function in the close region of a spherical homogeneous and heterogeneous head phantom. A formula, based on an application of an existing model proposed by Kuster and Balzano for dipole antennas, provides a rather accurate prediction of the induced Specific Absorption Rate (SAR) values in the human head due to the radiating helical antenna. The concept of relating the SAR to the current on the antenna is used in this study to formulate the final expression. Moreover, using the theory of regression, the results of the calculated peak or average SAR are correlated with the distance between the antenna and phantom and with the standing wave ratio (SWR) at the antenna feed point. Thus, the conception that the SAR is indeed related to the antenna operational parameters is reinforced by the outcome of the current study.

Abstract-A method of designing smart antennas based on switched parasitic antenna arrays is presented in this paper. The direction of maximum gain can be controlled by a digital word, while the selection of element spacing and weighting is optimized using the method of genetic algorithms. Various results are presented to show how antennas of this type perform, outlining the advantages and limitations of their design.

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Abstract-The technology of adaptive antennas is rapidly growing during the last years. It is true that switched beam antennas, the simplest type of smart antennas, may provide substantial benefits when implemented in a cellular mobile telephony system. The performance of a six-beam switched parasitic planar array, in terms of bit error rate (BER) measurement, is presented in this paper. The switched parasitic planar array is designed with the aid of genetic algorithms method. The antenna system is evaluated in a radio environment where interfering signals are present. The results obtained from the simulation are compared with respect to the ones when an omni directional antenna is used instead of the switched beam array, revealing that the performance of such a telecommunication system can be improved.