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Abstract-This letter presents the use of two heuristic search algorithms, named simulated annealing and genetic algorithms, for the extraction of power amplifier (PA) behavioral model parameters. Their application in this letter consists in determining the memory length and the most significant delays of the considered model structure. Two PA behavioral models have been considered: an augmented nonlinear moving average model and a nonlinear auto-regressive moving average model. By using WCDMA signals measured from a three-stage LDMOS class AB PA, both PA models were extracted. Finally, results presenting the advantages of using these heuristic search algorithms are provided.Index Terms-Behavioral models, genetic algorithm, heuristic search, power amplifier (PA), simulated annealing.

100 GHz-1.0 THz) technology is expected to provide unprecedented data rates in future generations of wireless system such as the 6 th generation (6G) mobile communication system. Increasing the carrier frequencies from millimeter wave to THz is a potential solution to guarantee the transmission rate and channel capacity. Due to the large transmission loss of Low-THz wave in free space, it is particularly urgent to design high-gain antennas to compensate the additional path loss, and to overcome the power limitation of Low-THz source. Recently, with the continuous updating and progress of additive manufacturing (AM) and 3D printing (3DP) technology, antennas with complicated structures can now be easily manufactured with high precision and low cost. In the first part, this paper demonstrates different approaches of recent development on wideband and high gain sub-millimeter-wave and Low-THz antennas as well as their fabrication technologies. In addition, the performances of the state-of-the-art wideband and high-gain antennas are presented. A comparison among these reported antennas is summarized and discussed. In the second part, one case study of a broadband high-gain antenna at 300 GHz is introduced, which is an all-metal model based on the Fabry-Perot cavity (FPC) theory. The proposed FPC antenna is very suitable for manufacturing using AM technology, which provides a low-cost, reliable solution for emerging THz applications.INDEX TERMS Antennas, low-terahertz, additive manufacturing (AM), high gain, Fabry-Perot cavity (FPC), low-cost, three-dimensional printing (3DP). I. INTRODUCTIONA.

Automated driving is seen as one of the key technologies that influences and shapes our future mobility. Modern advanced driver assistance systems (ADAS) play a vital role towards achieving this goal of automated driving. Depending on the level of automation, the ADAS takes over the complete or partial control of the movement of the car. Hence, it is mandatory that the system reacts reproducibly and safely in a wide range of possible situations. Especially in complex and potentially dangerous traffic scenarios a test system with the ability to simulate realistic scenarios is required. The authors present an implementation of a vehicle-in-the-loop (ViL) test system which accomplishes these goals in a defined environment. Of the great plenty of sensors stimulated in this context, the radar sensor takes a special position due to its robust and comprehensive information perceiving capability. Stimulating the automotive radar sensor in a ViL environment requires supporting the complex movements of the considered traffic scenarios. For this task, a modular and highly scalable radar target stimulator is necessary, which is capable of stimulating multiple independent moving targets with realistic parameters. The authors are discussing the underlying concepts of the suggested solution and are presenting its performance.