Ismail Nasr
University of Erlangen-Nuremberg
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Featured researches published by Ismail Nasr.
IEEE Transactions on Microwave Theory and Techniques | 2014
Ismail Nasr; Johannes Nehring; Klaus Aufinger; Georg Fischer; Robert Weigel; Dietmar Kissinger
This work presents a single- and dual-port fully integrated millimeter-wave ultra-broadband vector network analyzer. Both circuits, realized in a commercial 0.35-μm SiGe:C technology with an ft/fmax of 170/250 GHz, cover an octave frequency bandwidth between 50-100 GHz. The presented chips can be configured to measure complex scattering parameters of external devices or determine the permittivity of different materials using an integrated millimeter-wave dielectric sensor. Both devices are based on a heterodyne architecture that achieves a receiver dynamic range of 57-72.5 dB over the complete design frequency range. Two integrated frequency synthesizer modules are included in each chip that enable the generation of the required test and local-oscillator millimeter-wave signals. A measurement 3σ statistical phase error lower than 0.3 ° is achieved. Automated measurement of changes in the dielectric properties of different materials is demonstrated using the proposed systems. The single- and dual-port network analyzer chips have a current consumption of 600 and 700 mA, respectively, drawn from a single 3.3-V supply.
IEEE Transactions on Microwave Theory and Techniques | 2013
Ismail Nasr; Klaus Aufinger; Georg Fischer; Robert Weigel; Dietmar Kissinger
An integrated frequency agile quadrature E-band receiver is presented in this paper. The complete receiver is realized in a commercial 0.35-μm SiGe:C technology with an ft/fmax of 170/250 GHz. The receiver covers the two point-to-point communication bands from 71 to 76 GHz and from 81 to 86 GHz and the automotive radar band at 77 GHz. A wide tuning range modified Colpitts oscillator provides a local oscillator (LO) tuning range > 30%. A two-stage constant phase RC polyphase network is implemented to provide wideband in-phase quadrature LO signals. The measured phase imbalance of the network stays below 8° over the receivers frequency range. In addition the chip includes a wideband low-noise amplifier, Wilkinson power divider, down conversion mixers, and frequency prescaler. Each of the chips receiver I/Q paths shows a measured conversion gain above 19 dB and an input referred 1-dB compression point of -22 dBm. The receivers measured noise figure stays below 11 dB over the complete frequency range. Furthermore, the receiver has a measured IF bandwidth of 6 GHz. The complete chip including prescaler draws a current of 230 mA from a 3.3-V supply, and consumes a chip area of 1628 μm×1528 μm.
IEEE Journal of Solid-state Circuits | 2016
Ismail Nasr; Reinhard Wolfgang Jungmaier; Ashutosh Baheti; Dennis Noppeney; Jagjit Singh Bal; Maciej Wojnowski; Mustafa Emre Karagozler; Hakim Raja; Jaime Lien; Ivan Poupyrev; Saverio Trotta
This work presents a highly integrated 57-64 GHz 4-channel receiver 2-channel transmitter chip targeting short range sensing and large bandwidth communications. The chip is housed in an embedded wafer level ball grid array package. The package includes 6 integrated patch antennas realized with a metal redistribution layer. The receiver patch antennas have a combined antenna gain of ≈10 dBi while each transmitter antenna has a gain of ≈6 dBi. The chip features a wide tuning range integrated VCO with a measured phase noise lower than -80 dBc/Hz at 100 kHz offset. Each of the differential transmitter channels shows a measured output power of 2-5 dBm over the complete frequency range. In addition, one transmitter channel features a modulator that can be digitally programmed to operate in either radar or communication mode. Each of the receiver channels has a measured conversion gain of 19 dB, a single-side-band noise figure of less than 10 dB and an input referred 1 dB compression point of less than 10 dBm. With all channels turned on the chip consumes a current of 300 mA from a 3.3 V supply. The functionality of the chip is demonstrated for both sensing and short range wireless communications.
radio frequency integrated circuits symposium | 2012
Ismail Nasr; M. Dudek; Robert Weigel; Dietmar Kissinger
This paper presents a wide tuning range superharmonic coupled quadrature Colpitts VCO with high output power. The circuit was fabricated using a low-cost SiGe technology with an ft/fmax of 200/250 GHz. The quadrature VCO employs a novel area efficient coupling technique that uses second harmonic coupling. Downcoversion mixers are implemented to provide an intermediate frequency signal, enabling easier measurement. A phase imbalance below ±2° is measured between the quadrature outputs, over a 6 GHz tuning range. The quadrature VCO can be tuned between 55 and 76.5 GHz having a record tuning range of approx. 33%. Moreover, the quadrature VCO has a maximum measured output power of +10.5 dBm, and a minimum phase noise of -97 dBc/Hz. The overall chip draws 303mA from a 3.3V supply, where the quadrature VCO draws 140mA of the total current.
international microwave symposium | 2014
Johannes Nehring; Ismail Nasr; K. Borutta; Robert Weigel; Dietmar Kissinger
This paper proposes an integrated reflectometer for biomedical sensor read-out applications using a low-cost silicon-germanium technology. The heterodyne reflectometer consists of two integrated cross-coupled oscillators, a set of two directional couplers as well as Gilbert-Cell downconversion mixers. A dual phase-locked-loop architecture guarantees the phase lock of both on-chip signal sources to an external reference oscillator. An OSM-calibration was applied to the reflectometer and measurements of the complex reflection coefficient of an arbitrary device under test (DUT) showed excellent agreement with the results of a commercial vector network analyzer. As a proof of concept for sensor read-out, five solutions with different mixture ratios were characterized with a dielectric probe connected to the reflectometer.
IEEE Transactions on Vehicular Technology | 2015
Manuel Dudek; Ismail Nasr; Gabor Bozsik; Mohamed Hamouda; Dietmar Kissinger; Georg Fischer
In this contribution, we present a novel beam-control approach for automotive phased-array radar frontends. Since radar sensors are considered to be one of the means to enable future advanced safety functionality, we previously developed a system simulation environment that incorporates all involved domains and calculates all relevant high-level effects accurately. Subsequently, a generic phased-array FMCW radar frontend has been implemented and parameterized according to state-of-the-art SiGe components operating in the 77 GHz band. To demonstrate the advantages of an adaptively controlled beam for future safety applications, it is focused on curved traffic situations, which are calculated in a co-simulation incorporating a 3D-raytracer. A novel method for the control of the antenna characteristic is derived, which takes the specific curve geometry into account, and predictive enhancement features applied to it are elucidated, before their utilization and the resulting increase of system performance is computed. By adaptively coupling the radar sensor to the steering angle, thus directing its beam together with the ego-vehicle into the curve, its measurement range can be distinctly increased, which is providing more time for the safety system to react. This set of facts is first examined in a static view, by regarding only some specially selected timesteps, before a thorough analysis of the complete traffic scenario reveals the systems advantages from a dynamic point-of-view. As a result, the performance improvement of phased-array frontends applying adaptive beam-control compared to those with body-fixed nonsteerable beams is proven. Moreover, some results which are to be expected from such an advanced system, in case its full potential is evolved by implementing a scanning functionality, are provided as an outlook on future developments.
international microwave symposium | 2013
Ismail Nasr; Robert Weigel; Dietmar Kissinger
Millimeter-wave frequency-agile front-ends capable of operating at different frequency bands offer an attractive solution for multiband communications. In this paper we present a fully integrated wide-band quadrature receiver covering the two point to point communication bands from 71 to 76 GHz and 81 to 86 GHz and the automotive radar band at 77 GHz. The receiver was fabricated using a low-cost SiGe technology with an ft/fmax of 200/250 GHz. The chip contains a wide-band LNA, Wilkinson power divider, down conversion mixers, two stage polyphase network, VCO, and frequency prescaler. The VCO achieves an ultra high tuning range of 33% between 64 and 89 GHz. Each receiver path (I/Q) has a measured conversion gain between 17 to 23 dB over the operating frequency range. The receiver has a minimum NF of 8dB, and an input referred compression point of -22 dBm. The complete chip consumes 220mA of current from a 3.3 V supply.
IEEE Transactions on Microwave Theory and Techniques | 2017
Johannes Nehring; Martin Schütz; Marco Dietz; Ismail Nasr; Klaus Aufinger; Robert Weigel; Dietmar Kissinger
This paper addresses the miniaturization of microwave vector network analyzers (VNAs) and the future vision of the VNA on a chip. Therefore, a highly integrated two-port VNA with a multioctave bandwidth from 4 to 32 GHz is presented. The proposed system is based on a fully integrated radio-frequency frontend consisting of a two-port stimulus, a four-channel heterodyne receiver, and a wideband testset. The testset is comprised of on-chip multisection directional couplers. The chip is operated inside a hardware demonstrator using a 16-term calibration procedure. The measurement of arbitrary devices under test is in excellent agreement with commercial measurement equipment and showed a mean deviation from the reference measurement of 0.17 dB and 1.29° regarding the forward transmission of a coaxial 30-dB attenuator. The system and receiver dynamic ranges are 44–77 and 82–101 dB at a resolution bandwidth of 100 kHz over the full system bandwidth. The measurements are highly repeatable and are robust against drift over time. As a proof of concept, the developed integrated network analyzers are utilized in a biomedical sensing scenario with an external and an on-chip sensor. Both approaches showed good sensitivity regarding the mixture ratio of binary solutions of ethanol and methanol.
international microwave symposium | 2015
Dietmar Kissinger; Thomas Girg; Christopher Beck; Ismail Nasr; Hans-Peter Forstner; Maciej Wojnowski; Klaus Pressel; Robert Weigel
This paper provides an overview of millimeter-wave transceiver frontend concepts and realizations for wireless multi-Gbps communication applications. Different state-of-the-art heterodyne and direct-conversion frontend implementations in silicon-germanium technology (SiGe) with their related applications are presented. These include highly compact embedded transceiver solutions featuring novel antenna-in-package concepts for low-cost short-range indoor 60 GHz broadband Wi-Fi/WLAN and WPAN access points. Furthermore, highly integrated multi-band transmitter and receiver chipsets in the 70/80GHz E-Band as well as the complete 50-100 GHz frequency range for outdoor wireless backhaul point-to-point communication links and fixed local area network extension are outlined.
Proceedings of SPIE | 2016
Julia Wecker; Andreas Bauch; Steffen Kurth; Gauri Mangalgiri; Markus Gaitzsch; Marco Meinig; Thomas Gessner; Ismail Nasr; Robert Weigel; Dietmar Kissinger; Angelika Hackner; Ulrich Prechtel
Oxygen shows significant absorption lines in the millimeter wave spectrum. Resonators are widely used to achieve a strong absorption even with a short absorption paths length for concentration measurements. A sensor system based on a Fabry-Pérot resonator for oxygen measurements at ambient pressure is presented here. The Fabry-Pérot resonator consists of two metal mirrors with a diameter of 50 mm. For purpose of oxygen detection the resonator covers a frequency range between 55 GHz and 65 GHz with a resonant peak density between 1 GHz and 1.5 GHz, depending on the mirror distance, and a quality factor of approximately 7000. To achieve a compact sensor system the concept envisages two integrated transceiver circuits directly coupling to coaxial ports in the metal mirrors of the resonator. The integrated SiGe front-end addresses a frequency band from 50 GHz to 75 GHz. They are realized as heterodyne structures with integrated directional couplers, thus it is possible to measure scattering parameters. For first oxygen concentration measurements, the resonator sample was coupled to a commercially available Vector Network Analyzer. The cavity was filled with oxygen concentrations of 0% vol. and 20% vol. at ambient pressure and temperature resulting in a significant change of the quality factor for frequencies close to the oxygen absorption line at 60.6 GHz. The sensor does not contain hot components. This is an advantage compared to other oxygen sensors, like electrochemical or metal-oxide sensors.