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A flexible and easily configurable software defined transmitter/receiver (TX/RX) architecture is described, which allows the determination of the distorted complex transfer characteristics of a 3 port nonlinear outphasing power amplifier (PA) for application in a WCDMA base station. The TX/RX architecture is capable of generating high precision single sideband signals (SSB) using a DSP algorithm, which is almost insensitive to measurement errors and to the frequency response of the output measurement channel. Based on this an inverse predistortion function for a necessary linearization is calculated and implemented into a FPGA (field programmable gate array) through look-up-tables (LUT). The common base band and the differential phase angles are predistorted, resulting in a linearization of the PA.

This paper presents the implementation of a Digital-Component-Separator (DCS) for a LINC-transmitter (linear amplification using nonlinear components) on an FPGA (field programmable gate array). It investigates and estimates the bandwidth requirements for such a LINC system. The influence of bandwidth limitations on a digitally based LINC-transmitter for W-CDMA utilization is studied by simulations. Furthermore a LINC transmitter is proposed which employs a flexible image-reject- or a direct up-conversion-architecture for transmission of single or combined multi-carrier/channel W-CDMA signals using the phase-modulation approach. The sampling frequency can be chosen at a value up to 32 times (122.88MHz) the symbol rate of the W-CDMA chip rate of 3.84Mbits/s. Measurement results for a LINC transmitter are presented and discussed.

The composition of materials generally has an influence on its dielectric properties. Hence it may be possible to determine their composition using microwave dielectric spectra. However with complex materials like foodstuffs it is difficult to devise a suitable dielectric model. Therefore multivariate calibration methods are discussed here. With these calibrations it is also possible to process the measured scattering parameters directly. In this case it is not necessary to calculate the permittivity and more degrees of freedom are available for the design of a sensor. The direct processing of the S-parameters is demonstrated with a new transmissionline sensor.

In order to verify simulations of a concave lens based upon a photonic crystal, it was scaled and built for the application in the microwave range. Its field distribution was measured between 5.5 and 12 GHz. Due to the effective refractive index smaller than 1, focusing points were found in spite of the concave shape. The survey of the field distributions at the investigated frequencies leads to other possible applications of photonic crystals in the microwave and millimetre wave region, like beam-splitter and prism.