Home » International Journal

International Journal

Find a document written by the best international scientists in our secure database.

1110 documents found for International Journal
A new class of nondiffracting pulses based on focusing leaky waves
Walter Fuscaldo, Davide Comite, Alessandro Boesso, Paolo Baccarelli, Paolo Burghignoli, Alessandro Galli
Published online : 01-06-2018
Article Access
View abstract
In this work, we propose an azimuthally-invariant periodic leaky-wave (LW) radiator for the generation of Bessel beams and X-waves by means of backward cylindrical LWs at millimeter wavelengths. A rigorous framework is first outlined to understand the theoretical constraints of such a novel design. A specific attention is devoted to the impact of the attenuation constant on the focusing properties
Liquid-crystal-based amplitude tuner and tunable SIW filter fabricated in LTCC technology
Ananto E. Prasetiadi, Matthias Jost, Baerbel Schulz, Matthias Quibeldey, Torsten Rabe, Ruediger Follmann, Rolf Jakoby
Published online : 01-08-2018
Article Access
View abstract
Tunable microwave devices will play an important role in future wireless systems, in which high-frequency bands, e.g. millimeter waves, will become promising, due to its huge spectrum availability. At such frequency bands, liquid crystals (LCs) exhibit low microwave loss, which is excellent compared with the other tuning elements. In this paper, LC-based microwave components are fabricated by usin
Transfer of AlGaN/GaN RF-devices onto diamond substrates via van der Waals bonding
Thomas Gerrer, Volker Cimalla, Patrick Waltereit, Stefan Müller, Fouad Benkhelifa, Thomas Maier, Heiko Czap, Oliver Ambacher, Rüdiger Quay
Published online : 01-06-2018
Article Access
View abstract
We present a novel bonding process for gallium nitride-based electronic devices on diamond heat spreaders. In the proposed technology, GaN devices are transferred from silicon (Si) onto single (SCD) and polycrystalline diamond (PCD) substrates by van der Waals bonding. Load-pull measurements on Si and SCD heat spreaders at 3 GHz and 50 V drain bias show comparable power-added-efficiency and output
GaN-based single-chip frontend for next-generation X-band AESA systems
Patrick Schuh, Hardy Sledzik, Rolf Reber
Published online : 01-06-2018
Article Access
View abstract
A next generation of active electronically scanned array (AESA) antennas will be challenged with the need for lower size, weight, power, and cost. This leads to enhanced demands especially with regard to the integration density of the radio frequency-part inside a / module. The semiconductor material GaN has proven its capacity for high-power amplifiers (HPA), robust receive components as well as
Micromachining integration platform for sub-terahertz and terahertz systems
Vladimir Ermolov, Antti Lamminen, Jaakko Saarilahti, Ben Wälchli, Mikko Kantanen, Pekka Pursula
Published online : 01-06-2018
Article Access
View abstract
We demonstrate a sub-terahertz (THz) and THz integration platform based on micromachined waveguides on silicon. The demonstrated components in the frequency range 225?325 GHz include waveguides, filters, waveguide vias, and low-loss transitions between the waveguide and the monolithic integrated circuits. The developed process relies on microelectromechanical systems manufacturing methods and sili
Convolutional neural networks for parking space detection in downfire urban radar
Javier Martinez, Dominik Zoeke, Martin Vossiek
Published online : 01-06-2018
Article Access
View abstract
We present a method for detecting parking spaces in radar images based on convolutional neural networks (CNN). A multiple-input multiple-output radar is used to render a slant-range image of the parking scenario and a background estimation technique is applied to reduce the impact of dynamic interference from the surroundings by separating the static background from moving objects in the scene. A
Tunable -enhanced LC dual-band filtering at microwave frequencies in 0.13 µm SiGe BiCMOS
Farooq Amin, Sanjay Raman, Kwang-Jin Koh
Published online : 01-06-2018
Article Access
View abstract
This paper presents an active -enhanced LC dual-band band-pass filtering approach using parallel synthesis techniques at X- and Ku-bands in 0.13 m SiGe BiCMOS technology. By employing two independently tunable parallel LC-tanks with either in-phase and out-of-phase addition, independently tunable dual-band filtering is achieved. For higher out-of-band (OOB) attenuation, subtraction of the two 2-or
K/Ka-band dual-polarized SIW-fed lens antennas for Rx/Tx integration
Thomas Jaschke, Hans K. Mitto, Arne F. Jacob
Published online : 01-06-2018
Article Access
View abstract
This contribution deals with array elements for K/Ka-band satellite communication terminals. It proposes an end-fire design realized in substrate integrated waveguide technology and featuring dual-band functionality, and dual circular polarization. The latter is achieved by means of a dual-band orthomode transducer. An extended hemispherical dielectric lens ensures good matching and radiation prop
Design and demonstration of acoustically optimized, fully-printed, BST MIM varactors for high power matching circuits
Daniel Kienemund, Nicole Bohn, Thomas Fink, Mike Abrecht, Walter Bigler, Joachim R. Binder, Rolf Jakoby, Holger Maune
Published online : 01-06-2018
Article Access
View abstract
This work addresses the piezoelectric induced reduction of quality factor in fully-printed metal-insulator-metal (MIM) barium strontium titanate (BST) thick film varactors designed for high power operation. An acoustically optimized varactor design is presented and compared to a non-optimized high-power varactor. The design is utilized to present a narrowband acoustic suppression technique based o
Low-current cathode spatial harmonic magnetrons: analysis and realization based on metamaterial loaded slow wave structures
Nasrin Nasr Esfahani
Published online : 01-06-2018
Article Access
View abstract
This paper provides an overview of theory, design, simulation, and fabrication of novel spatial harmonic magnetrons (SHMs). An approximate analysis which provides the guidelines for the design and predicts the important characteristics of these devices will be presented. This analysis shows that the metamaterial loaded SHMs can start generating power with very small cathode current densities which
A multiport vector network analyzer with high-precision and realtime capabilities for brain imaging and stroke detection
Sebastian Poltschak, Markus Freilinger, Reinhard Feger, Andreas Stelzer, Abouzar Hamidipour, Tommy Henriksson, Markus Hopfer, Ramon Planas, Serguei Semenov
Published online : 01-06-2018
Article Access
View abstract
Medical imaging is of great importance for patients affected by stroke. Since an early examination of the patient is necessary for successful recovery, there is room to improve the existing capabilities of analysis. Common systems like magnetic resonance imaging or computed tomography are precise, but stationary, and therefore, not ideally suited for the early analysis of stroke. The presented mul
Multi-functional D-band / modulator/demodulator MMICs in SiGe BiCMOS technology
Sona Carpenter, Zhongxia Simon He, Herbert Zirath
Published online : 01-06-2018
Article Access
View abstract
This paper presents the design and characterization of a D-band (110?170 GHz) monolithic microwave integrated direct carrier quadrature modulator and demodulator circuits with on-chip quadrature local oscillator (LO) phase shifter and radio frequency (RF) balun fabricated in a 130 nm SiGe BiCMOS process with / of 250 GHz/400 GHz. These circuits are suitable for low-power ultra-high-speed wireless
A 219?266 GHz LO-tunable direct-conversion IQ receiver module in a SiGe HBT technology
P. Rodriguez Vazquez, J. Grzyb, N. Sarmah, B. Heinemann, U.R. Pfeiffer
Published online : 01-06-2018
Article Access
View abstract
This paper presents a fully-integrated direct-conversion fundamentally-operated mixer-first quadrature receiver module with a tunable LO in the 219?266 GHz band. It has been implemented in a 0.13-?m SiGe heterojunction bipolar transistor technology. It includes an on-chip LO path driven externally from the printed circuit board (PCB) connector level at 13.6?16.7 GHz. A hybrid coupler generates the
Automotive antenna diversity system for satellite radio with high phase accuracy in low SNR-scenarios
Simon Senega, Ali Nassar, Stefan Lindenmeier
Published online : 01-06-2018
Article Access
View abstract
For a fast scan-phase satellite radio antenna diversity system a noise correction method is presented for a significant improvement of audio availability at low signal-to-noise ratio (SNR) conditions. An error analysis of the level and phase detection within the diversity system in the presence of noise leads to a correction method based on a priori knowledge of the system's noise floor. This meth
Analysis of multipath and DOA detection using a fully polarimetric automotive radar
Tristan Visentin, Jürgen Hasch, Thomas Zwick
Published online : 01-06-2018
Article Access
View abstract
Multipath propagation occurs in many situations of radar measurements in complex environments. The unwanted effects range from interference over the radar channels, which causes amplitude fading and a corrupted direction of arrival (DOA) estimation, to the detection of ghost targets in an angle of arrival of the multipath direction. Due to the different number of reflections, polarimetric radars a
A 216?256 GHz fully differential frequency multiplier-by-8 chain with 0 dBm output power
M.H. Eissa, A. Malignaggi, M. Ko, K. Schmalz, J. Borngräber, A.C. Ulusoy, D. Kissinger
Published online : 01-06-2018
Article Access
View abstract
This work presents a fully differential wideband and low power 240 GHz multiplier-by-8 chain, manufactured in IHP's 130 nm SiGe:C BiCMOS technology with / = 300/500 GHz. A single ended 30 GHz input signal is multiplied by 8 using Gilbert cell-based quadrupler and doubler, and then amplified with a wideband differential 3-stage cascode amplifier. To achieve wide bandwidth and optimize for power con
Scanning microwave microscopy of buried CMOS interconnect lines with nanometer resolution
Xin Jin, Kuanchen Xiong, Roderick Marstell, Nicholas C. Strandwitz, James C. M. Hwang, Marco Farina, Alexander Göritz, Matthias Wietstruck, Mehmet Kaynak
Published online : 01-06-2018
Article Access
View abstract
This paper reports scanning microwave microscopy of CMOS interconnect aluminum lines both bare and buried under oxide. In both cases, a spatial resolution of 190 ± 70 nm was achieved, which was comparable or better than what had been reported in the literature. With the lines immersed in water to simulate high- dielectric, the signal-to-noise ratio degraded significantly, but the image remained as
KIT coaxial gyrotron development: from ITER toward DEMO
S. Ruess, K. A. Avramidis, M. Fuchs, G. Gantenbein, Z. Ioannidis, S. Illy, J. Jin, P. C. Kalaria, T. Kobarg, I. Gr. Pagonakis, T. Ruess, T. Rzesnicki, M. Schmid, M. Thumm, J. Weggen, A. Zein, J. Jelonnek
Published online : 01-06-2018
Article Access
View abstract
Karlsruhe Institute of Technology (KIT) is doing research and development in the field of megawatt-class radio frequency (RF) sources (gyrotrons) for the Electron Cyclotron Resonance Heating (ECRH) systems of the International Thermonuclear Experimental Reactor (ITER) and the DEMOnstration Fusion Power Plant that will follow ITER. In the focus is the development and verification of the European co
Radiometric accuracy and stability of sentinel-1A determined using point targets
Kersten Schmidt, Núria Tous Ramon, Marco Schwerdt
Published online : 01-06-2018
Article Access
View abstract
Sentinel-1A is a space-borne synthetic aperture radar (SAR) system developed in the frame of the Copernicus Program. The German Aerospace Center supported the radiometric and polarimetric calibration of Sentinel-1A by the analysis of point target responses of several acquisitions considering different modes, beams, and polarization channels. An elevation dependent bias, which had not been properly
Slow-wave coplanar waveguides based on inductive and capacitive loading and application to compact and harmonic suppressed power splitters
Francisco Aznar-Ballesta, Jordi Selga, Paris Vélez, Armando Fernández-Prieto, Jan Coromina, Jordi Bonache, Ferran Martín
Published online : 01-06-2018
Article Access
View abstract
In this paper, a slow-wave transmission line implemented in coplanar waveguide technology, based on simultaneous inductive and capacitive loading, is presented for the first time. The shunt capacitors are achieved by periodically etching transverse strips in the back substrate side, connected to the central strip through metallic vias. The series inductors are implemented by etching rectangular sl
Comparative study of envelope models for hybrid time- and frequency-domain simulation of traveling-wave tubes
Djamschid Safi, Philip Birtel, Sascha Meyne, Arne F. Jacob
Published online : 01-06-2018
Article Access
View abstract
A selection of hybrid frequency- and time-domain approaches is evaluated with respect to their suitability for predicting the multi-tone behavior of a reference Ku-band helix traveling-wave tube. For this, a frequency-domain code is extended by a selection of frequency-dependent and frequency-independent envelope models and compared to a number of simulated and measured responses to two-tone signa
MRF volume 10 issue 4 Cover and Back matter
Published online : 01-05-2018
Article Access
View abstract
MRF volume 10 issue 4 Cover and Front matter
Published online : 01-05-2018
Article Access
View abstract
Bandpass filters with + 1 transmission zeros using /4 resonator and /2 resonator
Di Lu, Xiao-Hong Tang, N. Scott Barker
Published online : 01-05-2018
Article Access
View abstract
The present paper presents a novel method to cope with the difficulty that an -order filter can introduce a maximum number of transmission zeros (TZs) ? no more than . The method is described by a coupling topology and realized by a regular fully canonical filter structure to increase one more TZ for an -order filter without any filter size increase. Besides, the TZ shift property, as another adva
An ultra-thin polarization independent quad-band microwave absorber-based on compact metamaterial structures for EMI/EMC applications
Naveen Mishra, Khusboo Kumari, Raghvendra Kumar Chaudhary
Published online : 01-05-2018
Article Access
View abstract
In this paper, a compact metamaterial inspired ultra-thin polarization independent quad-band microwave absorber for electromagnetic interference (EMI)/ electromagnetic compatibility (EMC) applications have been discussed. The proposed absorber structure offers four different absorption peaks having absorptivity of 97.02, 94.07, 91.72, and 98.20% at 3.40, 8.23, 9.89, and 11.80 GHz, respectively. Du
0 document found for International Journal

ArtWhere Création de site Internet