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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.

Relating coupling and external quality factor of a filter to the physical parameters of the structure which is the final step of any filter design is usually complicated due to geometrical complexities of the filter, or in the case of microstrip resonators due to the lack of the exact solution for the field distribution. Therefore, common approach is using time consuming full wave simulations. In this paper active learning method (ALM) which is a fuzzy-based modeling technique developed by a procedure algorithmically mimics the information-handling process of the human brain, is proposed to overcome this drawback. Modeling steps of an unknown function using ALM will be described using an illustrative example. Afterwards, the modeling approach will be implemented to model coupling factor between two coupled spiral resonators (SRs) for two different coupling structures and external quality factor of the same resonator. Accuracy of the extracted surfaces is validated using two different criteria. Using the extracted surfaces; a four pole chebychev bandpass filter was designed and fabricated. Good agreement between the measured response and simulation validated the accuracy of the extracted surfaces again. Comparing the fabricated SR filter with a square open loop resonator (SOLR) one demonstrates more than 70% of filter area reduction.

Surface acoustic wave (SAW) sensors for the detection of magnetic fields are currently being studied scientifically in many ways, especially since both their sensitivity as well as their detectivity could be significantly improved by the utilization of shear horizontal surface acoustic waves, i.e., Love waves, instead of Rayleigh waves. By now, low-frequency limits of detection (LOD) below 100 pT/Hz can be achieved. However, the LOD can only be further improved by gaining a deep understanding of the existing sensor-intrinsic noise sources and their impact on the sensor's overall performance. This paper reports on a comprehensive study of the inherent noise of SAW delay line magnetic field sensors. In addition to the noise, however, the sensitivity is of importance, since both quantities are equally important for the LOD. Following the necessary explanations of the electrical and magnetic sensor properties, a further focus is on the losses within the sensor, since these are closely linked to the noise. The considered parameters are in particular the ambient magnetic bias field and the input power of the sensor. Depending on the sensor's operating point, various noise mechanisms contribute to f0 white phase noise, f-1 flicker phase noise, and f-2 random walk of phase. Flicker phase noise due to magnetic hysteresis losses, i.e. random fluctuations of the magnetization, is usually dominant under typical operating conditions. Noise characteristics are related to the overall magnetic and magnetic domain behavior. Both calculations and measurements show that the LOD cannot be further improved by increasing the sensitivity. Instead, the losses occurring in the magnetic material need to be decreased.

Magnetoelectric (ME) thin film composites consisting of sputtered piezoelectric (PE) and magnetostrictive (MS) layers enable for measurements of magnetic fields passively, i.e. an AC magnetic field directly generates an ME voltage by mechanical coupling of the MS deformation to the PE phase. In order to achieve high field sensitivities a magnetic bias field is necessary to operate at the maximum piezomagnetic coefficient of the MS phase, harnessing mechanical resonances further enhances this direct ME effect size. Despite being able to detect very small AC field amplitudes, exploiting mechanical resonances directly, implies a limitation to available signal bandwidth along with the inherent inability to detect DC or very low frequency magnetic fields. The presented work demonstrates converse ME modulation of thin film Si cantilever composites of mesoscopic dimensions (25 mm × 2.45 mm × 0.35 mm), employing piezoelectric AlN and magnetostrictive FeCoSiB films of 2 µm thickness each. A high frequency mechanical resonance at about 515 kHz leads to strong induced voltages in a surrounding pickup coil with matched self-resonance, leading to field sensitivities up to 64 kV/T. A DC limit of detection of 210 pT/Hz 1/2 as well as about 70 pT/Hz 1/2 at 10 Hz, without the need for a magnetic bias field, pave the way towards biomagnetic applications.

We present a comprehensive study of a magnetic sensor system that benefits from a new technique to substantially increase the magnetoelastic coupling of surface acoustic waves (SAW). The device uses shear horizontal acoustic surface waves that are guided by a fused silica layer with an amorphous magnetostrictive FeCoSiB thin film on top. The velocity of these so-called Love waves follows the magnetoelastically-induced changes of the shear modulus according to the magnetic field present. The SAW sensor is operated in a delay line configuration at approximately 150 MHz and translates the magnetic field to a time delay and a related phase shift. The fundamentals of this sensor concept are motivated by magnetic and mechanical simulations. They are experimentally verified using customized low-noise readout electronics. With an extremely low magnetic noise level of ≈100 pT/[Formula: see text], a bandwidth of 50 kHz and a dynamic range of 120 dB, this magnetic field sensor system shows outstanding characteristics. A range of additional measures to further increase the sensitivity are investigated with simulations.