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KurzfassungRadio frequency( RF) power amplifiers (PA) are the most power consuming components of am obile communications unit. They are used to convert the DC power from the battery into RF power delivered to the antenna. In ac ell phone it becomes very important to use highly efficient power amplifiers, such as Class Ca nd Class EP As, to increase the talk time whichisdirectly proportional to the battery life. On the other hand, these RF PAsa re inherently nonlinear and produce spectral regrowth and other undesirable effects. Therefore, to exploit their high efficiency, it is desirable to employl inearization techniques to linearize their overall response. Linear model matching linearization techniques are investigated in this work to compensate for PA nonlinearities. Thea pplication of theses techniques results in a controller architecture that delivers excellent linearity performance of compensated Class CP Am odels, making Figure 1.6-1 shows the result of aT woTone Test. Themagnitude response plots of the uncompensated and compensated models are shown. Thet hird order products in the compensated case are suppressed significantly, at least by 18 dB and the fifth order intermodulation products are suppressed by 16 dB.Thei mprovement of noise behavior is shown in Figure 1.6-2, considering the result of the white noise test. Thepower spectraofthe input and of the output of the uncompensated and compensated models are shown. Thes pectrum of the output band-limited noise, in the compensated case, preserved the deep notch in the middle of the spectrum, whereas in the uncompensated case the notch wasfi lled-in significantly.T his test also provest he linear behavior of the compensated power amplifier.[1] Prof. Dr.M ario Magaña from the Oregon State University,U SA, has been at the University of Applied Science Offenburg in the summer semester 2008 for research and teaching.

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Several radio monitoring campaigns have been carried out in the past at different locations to determine the degree to which radio spectrum is currently used. The purpose of these measurement campaigns is to show if the radio spectrum, which is a non-expandable and non-importable national resource, is efficiently used at a certain place. Although all of these campaigns follow the similar approach, they are not comparable due to a lack of common measurement setups and evaluation methodologies. Moreover, none of these monitoring campaigns compare their measurement results with the corresponding spectrum management data. This work presents a novel evaluation methodology by taking the a priori data of the spectrum management into account. Starting with a precise description of the measurement setup and a definition of a newly defined threshold for signal detection, this study presents an evaluation methodology that automatically compares the measurement results with the corresponding spectrum management data in the frequency bands UHF IV and V. With this approach the monitoring system delivers beside the common spectrum occupancy value a novel signal identification index that indicates if the detected emission is listed in the spectrum management database. The spectrum management data used in this measurement campaign is a public transmitter database of the German regulator and the signal identification is based on the evaluation of the center frequency, bandwidth and spectral shape of the emission.

A simple measuring method for acquiring the radiation pattern of an ultra-wide band Vivaldi antenna is presented. The measuring is performed by combining two identical Vivaldi antennas and some of the intrinsic properties of a stepped-frequency continue wave radar (SFCW radar) in the range from 1.0 GHz to 6.0 GHz. A stepper-motor provided the azimuthal rotation for one of the antennas from 0 • to 360 •. The tests have been performed within the conventional environment (laboratory / office) without using an anechoic chamber or absorbing materials. Special measuring devices have not been used either. This method has been tested with different pairs of Vivaldi antennas and it can be also used for different ones (with little or no change in the system), as long as their operational bandwidth is within the frequency range of the SFCW radar.