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Item type:Publication, Access status: without files , Active multi-feed satcom systems with GaN SSPA at K-band(IEEE, 2016-03); ; ; ; The ongoing developments of satellite antenna technology, mainly of multiple-feed-per-beam (MFB) concepts, combined with advanced compound semiconductor and packaging technologies that provide the building blocks for a new generation of K-band satellites, are reported. This paper proposes a next-generation MFB application scenario using the advantages of both new antenna and solid-state power amplifier concepts.Publicationtype: Conference Paper100 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Determining linearity of wideband FMCW-systems based on low-cost Six-Port technologyThis paper describes a new method for high accuracy determination of instantaneous frequency and linearity of frequency modulated continuous wave systems. The presented setup reduces the frequency measurement to a phase measurement based on Six-Port interferometer with a delay line. To extend the range of possible input frequencies and power levels, a calibration method and the appropriate correction algorithm is introduced. Evaluation of linearity and frequency of the input signal is obtained without the use of computationally intensive Fourier transform which allows the signal processing based on low-cost micro-controllers.Publicationtype: Conference Paper92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The influence of rain on small aperture LiDAR sensorsThe influence of rain on pulsed LiDAR systems with a miniaturized aperture and small laser beam cross sections was investigated based on two situations deemed critical to the system's performance. Firstly, discrete rain drops appearing very close to the laser aperture could lead to a complete deflection of the laser beam when the drop and the beam overlap. However, our semi-probabilistic, semi-Analytical model indicates that the rate of deflected scan events is negligible. Secondly, the emitter surface could be covered with drops of various size degrading the performance. We found an optimum ratio between drop diameter and laser beam diameter, favoring larger laser beams. In conclusion, the effect was found to be non critical.Publicationtype: Conference Paper175 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Nose-cone loaded folded-waveguide delay lines for Q-band traveling-wave tubesA modified folded-waveguide (FW) delay line for traveling-wave tubes (TWTs) is proposed. The amplifier performance is assessed by full-wave and interaction simulation. Properly designed nose cones are shown to enhance the beam-wave coupling. This, in turn, improves the amplifier gain, a weak point of conventional FW-TWTs. The achievable beam efficiency is increased without sacrificing too much bandwidth.Publicationtype: Conference Paper87 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Probe-receiver coupling in external calibration systemsOn-line calibration systems with near-field probes are an attractive approach for large-size DBF arrays. In order to improve the calibration accuracy, a model of the coupling between the receiver patch and the calibration monopole probe is developed further in this contribution. A Fourier-based approximation of the radiation characteristic of the patch is proposed as a compromise between accuracy and computational effort. A planar array is built to validate the proposed concept. A phase error of 1.5° and an amplitude deviation of 0.8 dB are achieved in the experiments.Publicationtype: Conference Paper104 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Differential measuring dual six-port concept and antenna design for an inline foil thickness sensorSensor elements play an important role in future manufacturing plants. This paper presents a solution for a foil thickness sensor for running production lines. Based on the elaborated Six-Port principle, a differential measuring concept is proposed and discussed. Furthermore, an end-fire antenna design for the addressed application is demonstrated and far-field measurement results are shown and compared to simulation. Finally, interference effects between two antennas are experimentally investigated as a function of the relative rotation between two oppositely placed devices.Publicationtype: Conference Paper96 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A grounded coplanar waveguide resonator based in-line material characterization sensorMicrowave Materials such as Rogers RO3003 are subject to process-related fluctuations in terms of the relative permittivity. The behavior of high frequency circuits like patch-Antenna arrays and their distribution networks is dependent on the effective wavelength. Therefore, fluctuations of the relative permittivity will influence the resonance frequency and antenna beam direction. This paper presents a grounded coplanar wave-guide based sensor, which can measure the relative permittivity at 77 GHz, as well as at other resonance frequencies, by applying it on top of the manufactured depaneling. In addition, the sensor is robust against floating ground metallizations on inner printed circuit board layers, which are typically distributed over the entire surface below antennas.Publicationtype: Conference Paper175 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Design procedure for hot-matched severs in folded-waveguide traveling-wave tubesA design procedure for a hot-matched sever for folded-waveguide traveling-wave tubes (FW-TWTs) is proposed. To determine a starting point for a suitable load design, a realistic three-dimensional sever structure is developed using equivalent circuits and subsequent particle-free (cold) full-wave simulation. Additional wave impedance information, obtained by a small-signal eigenvalue analysis, is used to improve the termination for hot operation. The final full-wave optimization is then performed in the presence of the electron beam with only moderate computational effort. This procedure is applied to develop a sever structure for a given frequency point at Q-band. The simulated results support the approach.Publicationtype: Conference Paper93 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modeling and design of stepped transitions for substrate-integrated waveguidesA stepped transition in substrate-integrated waveguide (SIW) technology is presented. The transition changes the height of an SIW using multiple steps. The steps can be tuned by varying the length of shorted stubs which represents a generalization of a stepped-impedance transformer. An accurate equivalent circuit model of the steps is developed, that enables fast optimization. An exemplary transition is designed that features two frequency bands at 20 GHz and 30 GHz. For verification the model is compared to full-wave simulation and a back-To-back coplanar-waveguide (CPW) to full-height SIW transition is fabricated and measured.Publicationtype: Conference Paper92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Rx/Tx integration concepts for ground segment SatCom antenna arraysThis paper discusses antenna array integration concepts for combined receiver (Rx) and transmitter (Tx) terminals that can be used for ground based Ka-band satellite communications (SatCom). The combination of Rx and Tx enables very compact array architectures, which eases integration on mobile platforms. The associated challenges are discussed in the SatCom context and a comprehensive analysis of the array grids is carried out. Advanced dual-band antenna designs are presented for both tile and brick architecture. A dielectric-lens based wideband antenna is introduced as an element of a dual-band array in brick architecture. The approach eases the integration of the required passive and active circuitry.Publicationtype: Conference Paper100