Ingmar Kallfass
University of Stuttgart
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Publication
Featured researches published by Ingmar Kallfass.
IEEE Transactions on Terahertz Science and Technology | 2011
Ingmar Kallfass; Jochen Antes; Thomas Schneider; Fabian Kurz; Daniel Lopez-Diaz; Sebastian Diebold; H. Massler; A. Leuther; A. Tessmann
A wireless data link operating at a carrier frequency of 220 GHz is supporting a data rate of up to 25 Gbit/s in on-off-keyed PRBS as well as complex 256-QAM (quadrature amplitude modulation) transmission. The millimeter-wave transmit and receive frontends consist of active multi-functional millimeter-wave microwave integrated circuits (MMICs), realized in 50 nm mHEMT technology and packaged into split-block waveguide modules. The paper presents system considerations for wireless links in the 200-300-GHz range, discusses the design and performance of dedicated broadband transmit and receive MMICs, and presents link experiments. With an RF transmit power of -3.4-1.4 dBm in the IF frequency range from 0 to 20 GHz , a receiver conversion gain of better than -4.8 dB up to 270 GHz and an estimated noise figure of less than 7.5 dB at 220 GHz, a 231-1 PRBS with a data rate of up to 25 Gbit/s is transmitted over 50 cm and received with an eye diagram quality factor >;3 . At 10 Gbit/s, an uncorrected bit-error rate (BER) of 1.6·10-9 is measured over a distance of 2 m. A 256-QAM signal with approx. 14 Mbit/s is received with an uncorrected BER of 9.1·10-4.
IEEE Transactions on Microwave Theory and Techniques | 2011
Morteza Abbasi; Sten E. Gunnarsson; Niklas Wadefalk; Rumen Kozhuharov; Jan Svedin; Sergey Cherednichenko; Iltcho Angelov; Ingmar Kallfass; A. Leuther; Herbert Zirath
This paper presents the design and characterization of single-chip 220-GHz heterodyne receiver (RX) and transmitter (TX) monolithic microwave integrated circuits (MMICs) with integrated antennas fabricated in 0.1- μm GaAs metamorphic high electron-mobility transistor technology. The MMIC receiver consists of a modified square-slot antenna, a three-stage low-noise amplifier, and a sub-harmonically pumped resistive mixer with on-chip local oscillator frequency multiplication chain. The transmitter chip is the dual of the receiver chip by inverting the direction of the RF amplifier. The chips are mounted on 5-mm silicon lenses in order to interface the antenna to the free space and are packaged into two separate modules.
compound semiconductor integrated circuit symposium | 2008
A. Tessmann; Ingmar Kallfass; A. Leuther; H. Massler; M. Kuri; M. Riessle; M. Zink; Rainer Sommer; Alfred Wahlen; Helmut Essen; V. Hurm; M. Schlechtweg; O. Ambacher
In this paper, we present the development of advanced W-band and G-band millimeter-wave monolithic integrated circuits (MMICs) and modules for use in a high-resolution radar system operating at 210 GHz. A W-band frequency multiplier by six as well as a subharmonically pumped 210 GHz dual-gate field-effect transistor (FET) mixer and a 105 GHz power amplifier circuit have been successfully realized using our 0.1 mum InAlAs/InGaAs based depletion-type metamorphic high electron mobility transistor (mHEMT) technology in combination with grounded coplanar circuit topology (GCPW). Additionally, a 210 GHz low-noise amplifier MMIC was fabricated using our advanced 0.05 mum mHEMT technology. To package the circuits, a set of waveguide-to-microstrip transitions has been realized on 50 mum thick quartz substrates, covering the frequency range between 75 and 220 GHz. The presented millimeter-wave components were developed for use in a novel 210 GHz radar demonstrator COBRA-210, which delivers an instantaneous bandwidth of 8 GHz and an outstanding spatial resolution of 1.8 cm.
IEEE Transactions on Microwave Theory and Techniques | 2009
Morteza Abbasi; Rumen Kozhuharov; Camilla Kärnfelt; Iltcho Angelov; Ingmar Kallfass; A. Leuther; Herbert Zirath
Two single-chip frequency multiplier chains targeting 118 and 183 GHz output frequencies are presented. The chips are fabricated in a 0.1 ¿m GaAs metamorphic high electron-mobility transistor process. The D-band frequency doubler chain covers 110 to 130 GHz with peak output power of 5 dBm. The chip requires 2 dBm input power and consumes only 65 mW of dc power. The signal at the fundamental frequency is suppressed more than 25 dB compared to the desired output signal over the band of interest. The G-band frequency sextupler (×6) chain covers 155 to 195 GHz with 0 dBm peak output power and requires 6.5 dBm input power and 92.5 mW dc power. The input signal to the multiplier chain can be reduced to 4 dBm while the output power drops only by 0.5 dB. The unwanted harmonics are suppressed more than 30 dB compared to the desired signal. An additional 183 GHz power amplifier is presented to be used after the ×6 frequency multiplier chain if higher output power is required. The amplifier delivers 5 dBm output power with a small-signal gain of 9 dB from 155 to 195 GHz. The impedance matching networks are realized using coupled transmission lines which is shown to be a scalable and straightforward structure to use in amplifier design. Microstrip transmission lines are used in all the designs.
international conference on indium phosphide and related materials | 2009
A. Leuther; A. Tessmann; Ingmar Kallfass; R. Losch; M. Seelmann-Eggebert; Niklas Wadefalk; F. Schafer; J. D. Gallego Puyol; M. Schlechtweg; M. Mikulla; O. Ambacher
Different noise sources in HEMTs are discussed, and state-of-the-art low-noise amplifiers based on the Fraunhofer IAF 100 nm and 50 nm gate length metamorphic HEMT (mHEMT) process are presented. These mHEMT technology feature an extrinsic ƒT of 220 / 375 GHz and an extrinsic transconduction gm, max of 1300 / 1800 mS/mm. By using the 50 nm technology several low-noise amplifier MMICs were realized. A small signal gain of 21 dB and a noise figure of 1.9 dB was measured in the frequency range between 80 and 100 GHz at ambient temperature. To investigate the low temperature behaviour of the 100 nm technology, single 4 * 40 µm mHEMTs were integrated in hybrid 4 – 8 GHz (Chalmers) and 16 – 26 GHz (Yebes) amplifiers. At cryogenic temperatures noise temperatures of 3 K at 5 GHz and 12 K at 22 GHz were achieved.
optical fiber communication conference | 2013
Swen Koenig; Florian Boes; Daniel Lopez-Diaz; Jochen Antes; Ralf Henneberger; Rene Schmogrow; David Hillerkuss; Robert Palmer; Thomas Zwick; Christian Koos; Wolfgang Freude; O. Ambacher; Ingmar Kallfass; Juerg Leuthold
We demonstrate a single-input single-output photonic wireless link at 237.5 GHz with record 100 Gbit/s data transmission over 20 m. We use an optical heterodyne I/Q transmitter and a state-of-the-art active I/Q-MMIC at the receiver.
IEEE Journal of Solid-state Circuits | 2011
A. Tessmann; A. Leuther; V. Hurm; Ingmar Kallfass; H. Massler; M. Kuri; M. Riessle; M. Zink; Rainer Loesch; M. Seelmann-Eggebert; M. Schlechtweg; O. Ambacher
In this paper, we present the development of submillimeter-wave monolithic integrated circuits (S-MMICs) and modules for use in next-generation sensors and high-data-rate wireless communication systems, operating in the 300-500-GHz frequency regime. A four-stage 460-GHz amplifier MMIC and a 440-GHz class-B frequency doubler circuit have been successfully realized using our 35-nm InAlAs/InGaAs-based metamorphic high-electron mobility transistor (mHEMT) technology in combination with grounded coplanar circuit topology (GCPW). Additionally, a 500-GHz amplifier MMIC was fabricated using a more advanced 20-nm mHEMT technology. To package the submillimeter-wave circuits, a set of waveguide-to-microstrip transitions has been fabricated on both 50-μm-thick quartz and GaAs substrates, covering the frequency range between 220 and 500 GHz. The E-plane probes were integrated in a four-stage 20-nm cascode amplifier circuit to realize a full H -band (220 to 325 GHz) S-MMIC amplifier module with monolithically integrated waveguide transitions.
european microwave conference | 2008
Ingmar Kallfass; Sebastian Diebold; H. Massler; Stefan Koch; M. Seelmann-Eggebert; A. Leuther
This paper presents the design and performance of various millimeter-wave FET switches realized in a metamorphic HEMT technology. The single-pole multi-throw switch configurations are targeting wireless communication frontends and imaging radiometers at 60, 94 and 120 GHz. In SPDT switches, state-of-the-art insertion loss of 1.4 and 1.8 dB is achieved at 60 and 94 GHz, respectively. Rivalled only by PIN diode switches, an insertion loss of <2 dB is demonstrated up to 120 GHz. Shorted stubs are used to compensate for parasitic FET capacitance and allow for matching. Linearity data is presented for 60 and 94 GHz SPDT switches. A comprehensive comparison with state-of-the-art planar SPDT switches is included. A 2:6 switch network for multi-antenna transceivers achieves <4 dB insertion loss at 60 GHz.
international workshop on antenna technology | 2013
Heiko Gulan; Sebastian Beer; Sebastian Diebold; Christian Rusch; A. Leuther; Ingmar Kallfass; Thomas Zwick
In this paper a probe based measurement setup is presented that allows the characterization of antennas in the frequency-range between 220 GHz and 325 GHz. The radiation pattern, as well as the gain and the return loss of the antenna under test (AUT) can be measured. The limits of the system in terms of accuracy and dynamic range are given. To demonstrate its functionality a 240 GHz patch-antenna on Gallium Arsenide (GaAs) substrate is measured. A comparison between simulation and measurement shows very good agreement.
IEEE Microwave and Wireless Components Letters | 2009
Ingmar Kallfass; P. Pahl; H. Massler; A. Leuther; A. Tessmann; S. Koch; Thomas Zwick
A millimeter-wave monolithic integrated circuit power amplifier operating in the frequency range between 186 and 212 GHz is presented. The amplifier, dedicated to high-resolution imaging radar and communication systems, is realized in a 100 nm gate length metamorphic high electron mobility transistor technology. The three-stage design with four parallel transistors in the output stage achieves a linear gain of more than 12 dB and provides a saturated output power of more than 9 dBm and 7 dBm at 192 and 200 GHz, respectively.