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Papers by Michael Schlechtweg

IEEE Transactions on Electron Devices, 2001

Microwave, European Conference, 1997

Double recessed T-gate Al0.2Ga0.8As/In0.25Ga0.75As pseudomorphic HEMTs with 0.3 ¿m gate length an... more Double recessed T-gate Al0.2Ga0.8As/In0.25Ga0.75As pseudomorphic HEMTs with 0.3 ¿m gate length and different upper recess widths have been processed and analyzed. Systematic investigations concerning the correlation between drain ledge, breakdown voltage and power performance have been carried out. An optimum upper recess width has been identified which yields to a high drain-source breakdown voltage of about 24 V. A state

The 5th European Microwave Integrated Circuits Conference, Sep 1, 2010

ABSTRACT A novel balanced 210 GHz mixer MMIC with a measured IF bandwidth of more than 50 GHz and... more ABSTRACT A novel balanced 210 GHz mixer MMIC with a measured IF bandwidth of more than 50 GHz and an RF bandwidth of more than 100 GHz has been successfully developed in a 50 nm mHEMT technology. The mixer achieves a measured conversion loss of 17 dB. The measured LO-to-RF isolation is better than 17 dB in the relevant frequency range. Two Lange couplers are used to balance the design. The IF signal is tapped at the isolated RF coupler port to increase the IF bandwidth.

2013 European Microwave Integrated Circuit Conference, 2013

ABSTRACT In this paper a DC to 40 GHz single pole double throw (SPDT) switch based on GaAs metamo... more ABSTRACT In this paper a DC to 40 GHz single pole double throw (SPDT) switch based on GaAs metamorphic high electron-mobility transistors (mHEMTs) is presented. Characterization is carried out at ambient temperature and at 15 K. The insertion loss from DC to 40 GHz is smaller than 2.2 dB and 1.5 dB at 295 K and 15 K, respectively. The isolation is better than 17 dB. The switch with a size of 1 × 1 mm2 is dedicated to multi-purpose measurement setups at cryogenic temperature, but also operates at room temperature. Bias dependency, switch design and influence of illumination are discussed additionally.

2013 European Microwave Integrated Circuit Conference, 2013

2008 European Microwave Integrated Circuit Conference, 2008

ABSTRACT

2009 European Microwave Integrated Circuits Conference, Sep 1, 2009

ABSTRACT An active frequency-doubler MMIC achieving an output frequency of 300 GHz and its monoli... more ABSTRACT An active frequency-doubler MMIC achieving an output frequency of 300 GHz and its monolithic integration with a 300 GHz resistive mixer is presented. The frequency-doubler provides a broadband source with an average output power of -9.5 dBm and better than 10 % conversion efficiency in the frequency range from 250 to 310 GHz. At 300 GHz, a non-saturated output power of -6.4 dBm is measured at an input power of 1 dBm. A 300 GHz down-conversion mixer MMIC, combining the frequency-doubler with a resistive mixer, achieves a conversion loss of 20 dB in the RF range from 246 to 300 GHz. Both MMICs are realized in a metamorphic HEMT technology with 50 nm gate-length.

IEEE International Electron Devices Meeting 2003, 2000

The operation of AlGaN/GaN HEMTs on SiC substrate at V-band frequencies (50-75 GHz) is discussed.... more The operation of AlGaN/GaN HEMTs on SiC substrate at V-band frequencies (50-75 GHz) is discussed. Both common source and dual-gate AlGaN/GaN HEMTs on SiC substrate are optimized and investigated by active and passive load-pull measurements. At 60 GHz, a power density of ≥0.5 W/mm can be measured for a small common source AlGaN/GaN HEMT limited so far by the available input power of the newly developed load-pull system. A common source HEMT with Wg=0.18 mm yields a power density of 1.9 W/mm at 40 GHz and a linear power gain of ≥5 dB at 60 GHz, while several dual-gate AlGaN/GaN HEMTs of Wg=0.18 mm and 0.36 mm yield MSG/MAG values ≥12 dB at 60 GHz.

2012 7th European Microwave Integrated Circuit Conference, Oct 1, 2012

ABSTRACT

ABSTRACT This work introduces an innovative layout structure for lateral, low-resistance GaN-base... more ABSTRACT This work introduces an innovative layout structure for lateral, low-resistance GaN-based power transistors, designed for use in TO220 packages. Design aspects for large gate width transistor structures of up to 359 mm and the inhomogeneous power distribution on active area and metallization of such structures are discussed. The new layout is realized using an AlGaN/GaN-on-Si technology. The devices are packaged and characterized. Results are directly compared to those obtained from a conventional comb structure. The fabricated device achieves drain currents of up to 90 A and on-state resistances as low as 50 mO.

GaAs IC Symposium. IEEE Gallium Arsenide Integrated Circuit Symposium. 19th Annual Technical Digest 1997, 2000

ABSTRACT Two monolithic integrated transmitter circuits of a modulator driver and a modulator dri... more ABSTRACT Two monolithic integrated transmitter circuits of a modulator driver and a modulator driver with a 2:1 multiplexer for high-speed optical-fiber links are presented. The ICs featuring differential configuration were fabricated in a 0.2 μm gate-length enhancement and depletion HEMT technology with 60 GHz and 55 GHz fT. The modulator driver operates up to 25 Gb/s with an output voltage swing of 3.3 Vp-p at each output (corresponding to an internal current swing of 100 mA). The total voltage gain is 22 dB. The modulator driver with a integrated 2:1 multiplexer performs a data rate up to 30 Gb/s with an output voltage swing of 2.2 Vp-p at each output. Each circuit consumes 1.4 W power using a single supply voltage of -5 V

Microwave, MTT-S International Symposium, 1991

Coplanar lines for the millimeter-wave range are required to be of small dimensions, typically 25... more Coplanar lines for the millimeter-wave range are required to be of small dimensions, typically 25-50 μm (ground to ground spacing) for the Wand V-band respectively. The thickness of the metalization typically 0.5 to several microns, cannot be neglected. The effect of gold metalization on the impedance, propagation constant and attenuation is presented theoretically and experimentally for millimeter-wave coplanar lines on

Microwave, MTT-S International Symposium, 1992

Extensive attenuation data of coplanar lines on semi-insulating GaAs and InP are presented over t... more Extensive attenuation data of coplanar lines on semi-insulating GaAs and InP are presented over the frequency range 1-60 GHz. On-wafer measurements were used to obtain the S-parameters. A ground-to-ground spacing of 30, 60, and 120 μm, typical of that used in today's microwave and millimeter-wave integrated circuit applications, was investigated. The center line width (impedance) and the evaporated gold metal

Due to the poor thermal conductivity of GaAs, successful power amplifier design in coplanar techn... more Due to the poor thermal conductivity of GaAs, successful power amplifier design in coplanar technology requires careful thermal considerations. The influences of the active device geometry and mounting conditions have been investigated theoretically and experimentally to provide reliable thermal management design data. 50-µm thinning and flip-chip with thermal bump attachment on AlN or diamond exhibited temperature rises in the order

IEEE Transactions on Electron Devices, 2001

Microwave, European Conference, 1997

Double recessed T-gate Al0.2Ga0.8As/In0.25Ga0.75As pseudomorphic HEMTs with 0.3 ¿m gate length an... more Double recessed T-gate Al0.2Ga0.8As/In0.25Ga0.75As pseudomorphic HEMTs with 0.3 ¿m gate length and different upper recess widths have been processed and analyzed. Systematic investigations concerning the correlation between drain ledge, breakdown voltage and power performance have been carried out. An optimum upper recess width has been identified which yields to a high drain-source breakdown voltage of about 24 V. A state

The 5th European Microwave Integrated Circuits Conference, Sep 1, 2010

ABSTRACT A novel balanced 210 GHz mixer MMIC with a measured IF bandwidth of more than 50 GHz and... more ABSTRACT A novel balanced 210 GHz mixer MMIC with a measured IF bandwidth of more than 50 GHz and an RF bandwidth of more than 100 GHz has been successfully developed in a 50 nm mHEMT technology. The mixer achieves a measured conversion loss of 17 dB. The measured LO-to-RF isolation is better than 17 dB in the relevant frequency range. Two Lange couplers are used to balance the design. The IF signal is tapped at the isolated RF coupler port to increase the IF bandwidth.

2013 European Microwave Integrated Circuit Conference, 2013

ABSTRACT In this paper a DC to 40 GHz single pole double throw (SPDT) switch based on GaAs metamo... more ABSTRACT In this paper a DC to 40 GHz single pole double throw (SPDT) switch based on GaAs metamorphic high electron-mobility transistors (mHEMTs) is presented. Characterization is carried out at ambient temperature and at 15 K. The insertion loss from DC to 40 GHz is smaller than 2.2 dB and 1.5 dB at 295 K and 15 K, respectively. The isolation is better than 17 dB. The switch with a size of 1 × 1 mm2 is dedicated to multi-purpose measurement setups at cryogenic temperature, but also operates at room temperature. Bias dependency, switch design and influence of illumination are discussed additionally.

2013 European Microwave Integrated Circuit Conference, 2013

2008 European Microwave Integrated Circuit Conference, 2008

ABSTRACT

2009 European Microwave Integrated Circuits Conference, Sep 1, 2009

ABSTRACT An active frequency-doubler MMIC achieving an output frequency of 300 GHz and its monoli... more ABSTRACT An active frequency-doubler MMIC achieving an output frequency of 300 GHz and its monolithic integration with a 300 GHz resistive mixer is presented. The frequency-doubler provides a broadband source with an average output power of -9.5 dBm and better than 10 % conversion efficiency in the frequency range from 250 to 310 GHz. At 300 GHz, a non-saturated output power of -6.4 dBm is measured at an input power of 1 dBm. A 300 GHz down-conversion mixer MMIC, combining the frequency-doubler with a resistive mixer, achieves a conversion loss of 20 dB in the RF range from 246 to 300 GHz. Both MMICs are realized in a metamorphic HEMT technology with 50 nm gate-length.

IEEE International Electron Devices Meeting 2003, 2000

The operation of AlGaN/GaN HEMTs on SiC substrate at V-band frequencies (50-75 GHz) is discussed.... more The operation of AlGaN/GaN HEMTs on SiC substrate at V-band frequencies (50-75 GHz) is discussed. Both common source and dual-gate AlGaN/GaN HEMTs on SiC substrate are optimized and investigated by active and passive load-pull measurements. At 60 GHz, a power density of ≥0.5 W/mm can be measured for a small common source AlGaN/GaN HEMT limited so far by the available input power of the newly developed load-pull system. A common source HEMT with Wg=0.18 mm yields a power density of 1.9 W/mm at 40 GHz and a linear power gain of ≥5 dB at 60 GHz, while several dual-gate AlGaN/GaN HEMTs of Wg=0.18 mm and 0.36 mm yield MSG/MAG values ≥12 dB at 60 GHz.

2012 7th European Microwave Integrated Circuit Conference, Oct 1, 2012

ABSTRACT

ABSTRACT This work introduces an innovative layout structure for lateral, low-resistance GaN-base... more ABSTRACT This work introduces an innovative layout structure for lateral, low-resistance GaN-based power transistors, designed for use in TO220 packages. Design aspects for large gate width transistor structures of up to 359 mm and the inhomogeneous power distribution on active area and metallization of such structures are discussed. The new layout is realized using an AlGaN/GaN-on-Si technology. The devices are packaged and characterized. Results are directly compared to those obtained from a conventional comb structure. The fabricated device achieves drain currents of up to 90 A and on-state resistances as low as 50 mO.

GaAs IC Symposium. IEEE Gallium Arsenide Integrated Circuit Symposium. 19th Annual Technical Digest 1997, 2000

ABSTRACT Two monolithic integrated transmitter circuits of a modulator driver and a modulator dri... more ABSTRACT Two monolithic integrated transmitter circuits of a modulator driver and a modulator driver with a 2:1 multiplexer for high-speed optical-fiber links are presented. The ICs featuring differential configuration were fabricated in a 0.2 μm gate-length enhancement and depletion HEMT technology with 60 GHz and 55 GHz fT. The modulator driver operates up to 25 Gb/s with an output voltage swing of 3.3 Vp-p at each output (corresponding to an internal current swing of 100 mA). The total voltage gain is 22 dB. The modulator driver with a integrated 2:1 multiplexer performs a data rate up to 30 Gb/s with an output voltage swing of 2.2 Vp-p at each output. Each circuit consumes 1.4 W power using a single supply voltage of -5 V

Microwave, MTT-S International Symposium, 1991

Coplanar lines for the millimeter-wave range are required to be of small dimensions, typically 25... more Coplanar lines for the millimeter-wave range are required to be of small dimensions, typically 25-50 μm (ground to ground spacing) for the Wand V-band respectively. The thickness of the metalization typically 0.5 to several microns, cannot be neglected. The effect of gold metalization on the impedance, propagation constant and attenuation is presented theoretically and experimentally for millimeter-wave coplanar lines on

Microwave, MTT-S International Symposium, 1992

Extensive attenuation data of coplanar lines on semi-insulating GaAs and InP are presented over t... more Extensive attenuation data of coplanar lines on semi-insulating GaAs and InP are presented over the frequency range 1-60 GHz. On-wafer measurements were used to obtain the S-parameters. A ground-to-ground spacing of 30, 60, and 120 μm, typical of that used in today's microwave and millimeter-wave integrated circuit applications, was investigated. The center line width (impedance) and the evaporated gold metal

Due to the poor thermal conductivity of GaAs, successful power amplifier design in coplanar techn... more Due to the poor thermal conductivity of GaAs, successful power amplifier design in coplanar technology requires careful thermal considerations. The influences of the active device geometry and mounting conditions have been investigated theoretically and experimentally to provide reliable thermal management design data. 50-µm thinning and flip-chip with thermal bump attachment on AlN or diamond exhibited temperature rises in the order