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Item type:Publication, Access status: without files , Microwave impedance sensors for the dielectric characterization of liquidsTwo small coplanar waveguide impedance sensors for the characterization of liquids are introduced. A simplified two-step calibration procedure is developed. The first step defines the reference plane, which is set close to the sample. This yields a simple lumped element equivalent circuit model. Only two known materials, namely air and a 1.0% NaCl solution, are then needed to determine calibration curves for parameter extraction. The capability of the presented sensors to determine the permittivity of unknown liquids with low, moderate, and high loss up to about 12 GHz is analyzed. The major strengths of the proposed approach are broadband measurement capability, simplicity of the calibration procedure and potential for miniaturization.Publicationtype: Conference Paper159 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A 5 W AlGaN/GaN power amplifier MMIC for 25-27 GHz downlink applications(IEEE, 2018-03); ; ; ; This work presents the design and analysis of a 5 W power amplifier (PA) MMIC operating between 25 and 27 GHz. The technology used is the 0.1 μm AlGaN/GaN HEMT process of Fraunhofer IAF. To benchmark its performance around 26 GHz two preliminary designs are synthesized and analyzed. The measured results demonstrate for the final MMIC up to 5.2 W of output power associated with 32 % of power added efficiency (PAE). A peak PAE of 35 % was observed in continuous-wave (CW) operation at a drain supply voltage of 15 V.Publicationtype: Conference Paper199 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Dual-polarized dual-frequency antenna module for a maritime phased array radarA dual-polarized dual-frequency antenna module for a future commercial navigation radar is presented. The module is comprised of three X-band antenna columns as well as one S-Band antenna column. All antennas feature dual-polarization capability and are the basic antenna cell for a full phased array realization of the radar system.Publicationtype: Conference Paper160 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , On the design of active Rx/Tx-diplexers with wide frequency spreadThis contribution deals with the performance analysis of an active diplexer for Rx/Tx integrated satellite communication antenna systems. To ensure a low noise figure of the receiver a passive diplexer with low insertion loss cascaded with a low noise amplifier (LNA) and a band-pass filter is used to separate Rx from Tx. This approach may lead to a relatively high Tx power level at the LNA input, which could even drive the latter into compression and affect the bit error rate (BER). This work analyzes the influence of phase and amplitude compression on the BER for different modulation schemes. Two-tone measurements are performed to characterize two different commercially available low noise amplifiers. The measured results are used to analyze the performance degradation for modulation schemes that are commonly used in Satcom. Maximum power levels of the parasitic Tx signal which prevent a significant rise in the BER are inferred. This information is useful for the design of diplexers.Publicationtype: Conference Paper239 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Fast dual-synthesizer for six-port in-situ linearization in the 2.4 GHz ISM-band(2018-04-10); ; ; ; The fourth industrial revolution requires sensors and new measuring methods in different fields. Novel six-port based techniques for measuring the resonant frequency of surface acoustic wave (SAW) sensors and calculating the underlying physical parameter from this frequency are very promising. This paper presents a fast and highly isolated radio frequency (RF) dual synthesizer in the 2.4 GHz Industrial, Scientific and Medical (ISM)-band for linearization of the six-port with several frequencies and attenuation steps which enhances the measurement results. This synthesizer is indispensable in the frequency measurement technique of resonant SAW sensors using a six-port interferometer.Publicationtype: Conference Paper61 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Frequency agile filter for image frequency rejection in an adjustable receiver frontend(2018-04-10); ; ; ; In this paper the investigation on a frequency agile filter circuit with bandpass-bandstop characteristic is presented. The filter is intended for an application in a frequency agile RF frontend. First of all, a theoretical examination of the tuning behavior for a second order tunable bandstop filter is conducted with analytic calculations and simulations. Main focus is on the constant frequency difference between passband and stopband in the whole tuning range. Subsequently, the proof of concept is established by implementing two demonstrator filter circuits using SMD components. Therefore, the lack of access to tunable inductances is solved by either switching inductances or changing the circuit topology according to the requirements.Publicationtype: Conference Paper92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Enhanced mobile node design for small size animal borne wireless sensor nodes with encounter detection and localization(2018-04-10); ; In this paper an enhanced version of the mobile node developed in the BATS project for small sized animals like bats is proposed. The new design uses highly integrated components and a more compact design. In the paper the new design is described with focus on the conducted changes. The new design has been proven in field test in Germany from which first results are shown. Special focus is put on the power supply and mobile node runtime. For pure encounter detection a runtime of more than 420 hours has been recorded. Without any communication with other nodes the current is as little as 50 μA while still being in active mode.Publicationtype: Conference Paper79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Two Q-band power amplifier MMICs in 100 nm AlGaN/GaN HEMT technology(IEEE, 2018-03); ; ; ; Two power amplifier (PA) MMIC designs with more than 1W of output power in the 37.5-42.5 GHz Q-band downlink band are presented. The circuits are manufactured using the Fraunhofer IAF 100 nm AlGaN/GaN process. The first one is a two-stage design in microstrip line (MSL) technology, whereas the second one is a three-stage design in grounded coplanar waveguide (GCPW) technology, which enables effective output power combining and compact layout at Q-band. A maximum output power of 2.1 W (33.2 dBm) is measured at 39 GHz with a power-added efficiency (PAE) of 14.7%, corresponding to a power density of 1.45 W/mm.Publicationtype: Conference Paper260