A5045630585- Antenna Design and Analysis
- Electromagnetic Compatibility and Measurements
- Advanced Antenna and Metasurface Technologies
- Antenna Design and Optimization
- Microwave Engineering and Waveguides
- Millimeter-Wave Propagation and Modeling
- Energy Harvesting in Wireless Networks
- Microwave and Dielectric Measurement Techniques
- Advanced SAR Imaging Techniques
- Advanced MIMO Systems Optimization
- Ovarian cancer diagnosis and treatment
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Geophysical Methods and Applications
- Metamaterials and Metasurfaces Applications
- Radio Astronomy Observations and Technology
- Electromagnetic Compatibility and Noise Suppression
- Full-Duplex Wireless Communications
- Atomic and Subatomic Physics Research
- Microwave Imaging and Scattering Analysis
- Advanced MRI Techniques and Applications
- Wireless Body Area Networks
- Electromagnetic Fields and Biological Effects
- Robotics and Sensor-Based Localization
- Medical Imaging Techniques and Applications
- RFID technology advancements
RWTH Aachen University
2015-2024
Fraunhofer Institute for High Frequency Physics and Radar Techniques
2017-2024
University of Duisburg-Essen
2024
Deutsche Forschungsgemeinschaft
2024
Tokyo Institute of Technology
2024
University College London
2024
Conference Board
2024
Forschungszentrum Jülich
2015-2020
Jülich Aachen Research Alliance
2015-2020
Westfälische Hochschule
2017
Combining Positron Emission Tomography (PET) with Magnetic Resonance Imaging (MRI) results in a promising hybrid molecular imaging modality as it unifies the high sensitivity of PET for and cellular processes functional anatomical information from MRI. Digital Silicon Photomultipliers (dSiPMs) are digital evolution scintillation light detector technology promise SNR. DSiPMs Philips Photon Counting (PDPC) were used to develop preclinical PET/RF gantry 1-mm crystal pitch an insert clinical MRI...
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, tune-defined as number of precessions per turn-is given by ν(s)=γG (γ Lorentz factor, G gyromagnetic anomaly). At 970 MeV/c, deuteron spins coherently precess at a frequency ≈120 kHz in Cooler Synchrotron COSY. The deduced from up-down asymmetry deuteron-carbon scattering. time interval 2.6 s, was determined with precision order 10^{-8}, 1×10^{-10} for continuous 100 s accelerator cycle. This...
We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of magnetic storage ring (COSY). This long spin coherence time is maintained through combination bunching, electron cooling, sextupole field corrections, and suppression collective effects current limits. record required for search an intrinsic electric dipole moment on at statistical sensitivity level approaching 10^{-29} e cm.
The advent of new, multistandard mobile phone devices is an important challenge for antenna designers, as they have to implement integrated antennas with multiband operation within a volume that rapidly shrinking. In the paper, research results concerning input return loss, radiation characteristics and efficiency novel internal, planar, patch are presented.
The combination of Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) into a single device is being considered promising tool for molecular imaging as it combines the high sensitivity PET with functional anatomical images MRI. For highest performance, scalable, MR compatible detector architecture small form factor needed, targeting at excellent signal-to-noise ratios time-of-flight information. Therefore desirable to use silicon photo multipliers digitize their signals...
Based on the investigation of board effect bandwidth integrated antennas for mobile phones a concept tripleband antenna suitable GSM/DCS/PCS is developed. The comprises parasitic element to enlarge bandwidth. performance analyzed by means numerical simulations based FDTD method.
This Letter reports the successful use of feedback from a spin polarization measurement to revolution frequency $0.97\text{ }\text{ }\mathrm{GeV}/c$ bunched and polarized deuteron beam in Cooler Synchrotron (COSY) storage ring order control both precession rate ($\ensuremath{\approx}121\text{ }\mathrm{kHz}$) phase horizontal component. Real time synchronization with radio (rf) solenoid made possible rotation out plane, yielding demonstration method manipulate polarization. In particular,...
A main drawback of near-field measurement techniques is the long time which a strong limiting factor in many measurements. The reason for this large number required points and reduction without loss accuracy hence desirable. In spherical measurements relevant information mostly concentrated few wave coefficients. Methods from compressed sensing (CS) exploit structure to reduce efforts if it properly adapted theory far-field transformation. paper, requirements challenges CS application...
The stable spin direction of polarized particles in a storage ring was determined first experimentally, through an accurate measurement the tune and its response to longitudinal magnetic fields.
Spherical wave expansion algorithms based on matrix inversion are flexible. They allow arbitrary sampling schemes and higher order probe correction. However, the correction technique assumes, up until now, same measurement at every point. This is a limitation, especially for dual-polarized probes multiprobe systems. In this communication, spherical near-field (SNF) far-field transformation procedure, including pointwise correction, presented. For sphere with constant radius, additional...
The paper demonstrates that double unit-cell asymmetry in periodic leaky-wave antennas (P-LWAs), i.e. with respect to both the longitudinal and transversal axes of structure -- or (LA) (TA) allows for simultaneous broadside radiation two orthogonal modes excited at ports antenna. This means antenna may simultaneously support channels, which represents an interesting polarization diversity characteristics wireless communications. asymmetric (DA) unit cell combines a circularly polarized LA...
The roll-out of the 5G standard with novel functionalities brings it urgent need to evaluate human exposure massive-MIMO base stations. This paper discusses concepts for measurement instantaneous and maximal in sub-6 GHz frequency range (FR1). have been implemented NARDA SRM-3006 selective radiation meter. For exposure, Safety Evaluation mode an averaging over multiple sweeps has identified appropriate. First results provoked data traffic revealed exposures below 0.25 % ICNIRP 1998 power...
The proposed method exploits charged particles confined as a storage ring beam (proton, deuteron, possibly $^3$He) to search for an intrinsic electric dipole moment (EDM) aligned along the particle spin axis. Statistical sensitivities could approach 10$^{-29}$ e$\cdot$cm. challenge will be reduce systematic errors similar levels. adjusted preserve polarisation, initially parallel velocity, times in excess of 15 minutes. Large radial fields, acting through EDM, rotate polarisation from...
In this paper, an improved method for measuring the radiation efficiency of small devices is introduced. The based on Wheeler's principle antenna impedance within two controlled environments: free space and a closed metallic box. addition to network model, extended equivalent circuit introduced, that gives exact description behavior device This model basis determination efficiency, independent size box location Several measurements show using new method, mobile can be determined very quickly...
Near-field-to-far-field transformation algorithms have been developed during the last decades of century. Spherical near-field measurements are nowadays most accurate technique for characterizing one antenna. However, drawbacks is requirement a full spherical acquisition. This means large number scans, especially very antennas, requiring long measurement time. paper presents several techniques performing single-cut near-to-far-field transformation. An explanation each algorithm, and...
A novel reconfigurable antenna capable of rotating a bidirectional pattern by 360° in azimuth is proposed. The has two ports, no aperture switching components, and offers more compact solution than an array. It provides the band 2.525-2.595 GHz fixed omnidirectional from 2.235 to 2.725 GHz. measured gains for four investigated configurations are between 2.1 3.1 dBi with total efficiencies 80% 89%. intended operate software defined radio [digital beamforming or multiple-input-multiple-output...
An omnidirectional circularly polarized antenna with a rotatable dipole-shaped radiation pattern is proposed. The realized using back-to-back coupled microstrip patch arrangement. rotated by means of phase shift, enabling reception (or transmission) signals from all angles around sphere. method enables continuous steering without the need for semiconductor or MEMS components integrated into antenna. It also allows use more than one simultaneously, potentially providing coverage any spherical...
This paper proposes an improved technique to calculate the Envelope Correlation Coefficient (ECC) by directly using spherical mode spectrum of antenna under test. The avoids errors due numerical pattern integration and simplifies post-processing for near-field measurements. is successfully tested on two different types, in total number four MIMO configurations.
The far-field radiation pattern of an antenna under test (AUT) can be derived via a spherical wave expansion near-field measurement data. transformation as well the time scales with number mode coefficients which depends on radius sphere enclosing antenna. In existing procedures, is measured from center sphere. Thus, increases for offset-mounted so that more are required to represent electromagnetic field. this communication, procedure proposed where origin specified independently With...
Design and characterization of a multilayer structure consisting stacked frequency selective surfaces (FSS) combined with patterned laminate absorber is presented. The FSS part higher order bandpass filter that operates in the C-band, namely from 5 GHz to 6 GHz. Its response achieved through stacking capacitive-inductive-capacitive layers maintain low-profile structure. glued on one side so resulting capable absorbing signals X-band (receiving mode). prototype has been fabricated using...