In this paper, a rectangular metallic ring FSS (Frequency Selective Surfaces) with parallel metallic strips for multi band applications are characterized by the WCIP (Wave Concept Iterative Procedure) method. The proposed FSS structures are made of metallic elements that are simultaneously independent in the spatial domain and uncoupled in the spectral domain. Thus the FSS multiband behavior can be achieved only by a building process based on independent metallic elements in both domains. The resonant characteristics of the proposed FSS are determined. The structure shows three resonant frequencies when the incident wave is x-polarized and three resonant frequencies when the source is polarized in the orthogonal direction. A variation in the length of the strips and the rectangular ring allows a fine tuning in the FSS resonant frequencies to give raise to tuned bandwidths. The suppression of a resonant frequency can be insured either by the elimination of the responsible metallic strip or by the insertion of a PIN diode switch. Three FSS structures are manufactured and characterized. The FSS bandwidth can be enhanced in both perpendicular FSS exciting source directions by only varying the strips lengths and the ring dimensions to the corresponding resonant frequencies. A good agreement is obtained when the WCIP results are compared with the simulations of COMSOL Multiphysics software and experiment.

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A novel parallel non coupled metallic strips frequency selective surface (FSS) is presented. The design is based on a filter composed of horizontal and vertical metallic strips. The structure has the advantage of simplicity and gives multi resonant frequencies easily controlled by a simple variation in the strips length. The proposed FSS rejects frequencies at 7GHz, 9.4GHz with bandwidths of 0.646GHz, 0.793GHz respectively when the structure is excited with an x polarized plane wave, and two frequencies at 9.1GHz and 11.2 GHz with bandwidth of 280.3MHz, 63MHz respectively when the structure is excited with a y polarized plane wave. To suppress frequencies ideal diode on reverse bias are inserted. The simulated results obtained using WCIP (Wave Concept Iterative Method) are compared to the COMSOL Multiphysics 4.3b software results, and measurements, a good agreement is observed. Then, an FSS synthesis approach based on non coupled parallel metallic strips is presented. It provides synthesized FSS with resonant frequencies ranging from 4.5GHz and 12.25 GHz for metallic strips lengths inversely varying from 5mm to 19mm. To validate the synthesis approach, measured resonant frequencies are used as desired resonant frequencies to determine the metallic strips lengths. As a result the metallic strips FSS dimensions are extracted. At this stage the WCIP method is used to characterize the synthesized FSS. Three FSSs are synthesized based on the fabricated FSS and good agreement between measurements and synthesized FSSs results is recorded.

The study of propagation characteristics is a fundamental step in mobile radio engineering; which is intended to achieve maximum performance for a mobile radio system. To do this, the propagation models are essential tools for this study such as the evaluation of the signal strength received by a mobile terminal, the evaluation of coverage radii and deduce the number of cells needed to cover a given area, such as radio planning, which in turn is the step that aims to estimate the necessary equipment and configurations of the radio interface. In this work we adopt the standard K factor model and OKUMURA HATA model to demonstrate a propagation model adapted to the physical environment of the city of Annaba in Algeria using a linear regression algorithm based on the ordinary least squares method. Radio measurements were carried out on the CDMA network of operator Mobilis. The calculation of the square root of the mean square error between the actual data and the radio measurements and the prediction data derived from the model implemented allowing the validation of the results obtained. A comparative study between the value of the RMSE obtained by the new model and those obtained by the models K standard factors and the model of OKUMURA HATA allows us to conclude that the new model is better adapted to our local environment than that of OKUMURA HATA. The new model obtained can help increase the performance of mobile radio systems deployed in our territory.Keywords: Model K factor, Model of OKUMURA HATA Linear regression. IntroductionTo obtain a propagation model that accurately reflects propagation characteristics radio in a given environment. It is necessary to rely on network coverage, the capacity of the network as well as the quality of service of it which are the essential points of a network planning. In order to have access to all the services offered by a network, it is necessary to give particular importance to the dimensioning of the latter. The use of propagation models is very widespread for the planning and installation of networks or also for the extensions of already existing networks, especially in the new towns. Contributing to the improvement of the performance of mobile radio systems. To determine the characteristics of the radio propagation channel, the tests of the concrete propagation modes and the calibration of the existing models are essential to have a propagation models that accurately represent the radio propagation characteristics of the environment being studied. Several types of software allow the improvement of the performance of mobile radio systems through the planning and sizing of mobile networks including prediction models namely: ASSET of AIRCOM company in England, Atoll of the French company FORK ... etc.Some authors investigate the calibration of propagation models, Like Chhaya Dalila, and Garlic

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