Partial transmit sequence (PTS) is a potent and distortionless scheme frequently used to lower the high peak-to-average power ratio (PAPR) levels in orthogonal frequency division multiplexing (OFDM) signaling. Although this method effectively reduces the PAPR, its main limitation is the exponential growth in the computational expense caused by the exhaustive search for the optimal complex of rotation factors. This work proposes a suboptimal PTS scheme based on an improved particle swarm optimization (PSO) algorithm. The latter exploits heuristics to find the best-matched weighting factors complex in fewer computations. A comparison against existing techniques ascertains the superior efficiency of the proposed scheme in terms of PAPR mitigation and computational burden.

Over the past few years, the continuous evolution of embedded electronic systems has increased electromagnetic interferences problems. It has also generated a new design constraint on electromagnetic compatibility. Hence, predicting the electromagnetic field behavior in the vicinity of the electronic components and systems becomes a priority to avoid the potential for unwanted coupling occurrence, as well as to ensure the electromagnetic compatibility compliance for those components and systems which are embedded in a confined space. As a result, the designers of electronics' equipment are extremely interested in radiated emission models. This paper reports a comparative study in which two different methods will be applied: the equivalent source method and plane wave spectrum method. These two methods will be used to predict the magnetic field behavior in the vicinity of a microstrip patch antenna. The latter works in ISM band for Wi-Fi and Bluetooth applications. The two applied models are constructed from the tangential magnetic fields cartographies of the antenna obtained from HFSS R at 3.5 mm and validated by comparing the HFSS R results with those of the models at a higher elevation. Furthermore, the relative error between the simulated field of the antenna and those of the equivalent source model according to the dipoles number is presented to determine the minimum number of dipoles that allow users to obtain the results with better accuracy. Subsequently, the relative error as function of different elevations along the z axis together with the two methods comparison results is presented.

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Over the past decade, the evolution of embedded system has taken place drastically as it has been for their integration in various industries. This increases Electro-Magnetic Interferences (EMI) problems and generates new design constraints on Electro-Magnetic Compatibility (EMC). Thus, the nature of the electromagnetic environment and the prospective for undesired coupling must be taken into consideration by embedded systems engineers to avoid the equipment failure or malfunction. Accordingly, the radiated emission models are of great interest to designers of electronic equipment. This paper exploits the Plane Wave Spectrum (PWS) technique to predict and compute the magnetic field at various distances till 100 mm above a Device Under Test (DUT). Good similarities are obtained between the magnetic field components calculated by PWS and the simulated ones by HFSS at different elevation from the electric dipole.