M. Schlechtweg

Metamorphic HEMT MMICs and Modules for Use in a High-Bandwidth 210 GHz Radar

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.

50 nm MHEMT Technology for G- and H-Band MMICs

A metamorphic HEMT (MHEMT) MMIC technology including circuit applications is presented. The MHEMT layers are MBE grown on 4-inch GaAs wafers. The technology is based on a 50 nm gate length MHEMT and includes a 50 mum substrate backside process with dry etched through-substrate vias. For the electron confinement an ln_0.8Ga_0.2As/ln_0.53Ga_0.47As composite channel was used. The devices are passivated with BCB and SiN to achieve a median time-to-failure of 2.7 times 10⁶ h in air. Cut-off frequencies f_t and f_max of 375 GHz were extrapolated for a 2 times 15 mum gate width device. Low-noise amplifiers with more than 15 dB gain in the frequency range from 192 GHz to 235 GHz were realized.

A simplified broad-band large-signal nonquasi-static table-based FET model

In this paper, a simplified nonquasi-static table-based approach is developed for high-frequency broad-band large-signal field-effect-transistor modeling. As well as low-frequency dispersion, the quadratic frequency dependency of the /spl gamma/-parameters at high frequencies is taken into account through the use of linear delays. This model is suitable for applications related to nonlinear microwave computer-aided design and can be both easily extracted from dc and S-parameter measurements and implemented in commercially available simulation tools. Model formulation, small-signal, and large-signal validation will be described in this paper. Excellent results are obtained from dc up to the device f/sub T/ frequencies, even when f/sub T/ is as high as 100 GHz.

220 GHz Low-Noise Amplifier Modules for Radiometric Imaging Applications

G-band low-noise amplifier (LNA) modules have been successfully developed for use in high-resolution radiometric imaging applications. The WR-5 waveguide modules contain a four-stage 220 GHz cascode LNA MMIC and two microstrip-to-waveguide transitions which were realized on 50 mum thick quartz substrates. The monolithic amplifier circuits were fabricated using a well proven 0.1 mum InAlAs/InGaAs metamorphic high electron mobility transistor (MHEMT) technology in combination with grounded coplanar waveguides (GCPW). Furthermore, an MMIC based 220 GHz direct detection radiometer was developed, for the first time, containing three amplifier modules connected in series and demonstrating a small-signal gain of more than 50 dB over the frequency range from 209 to 217 GHz

51 GHz frontend with flip chip and wire bond interconnections from GaAs MMICs to a planar patch antenna

In this paper the difference between flip chip and wire bond technology is demonstrated. Test assemblies with coplanar waveguides have been attached in flip chip and wire bond technology and measured up to 75 GHz. Further, the influence of a metallic lid on a coplanar waveguide structure is examined. To compare flip chip and wire bond interconnections, 51 GHz frontends with GaAs devices in coplanar waveguide technology have been realized. In one frontend the low noise amplifier (LNA) is connected to a planar patch antenna by wire bonding and in a second one by flip chip attachment. RF evaluations show the clear advantage of the flip chip version due to the lower insertion loss of the flip chip interconnections and the higher flexibility of mounting the MMICs directly on the back structure of the planar patch antenna, leading to reduced losses of the feedline.<<ETX>>

Metamorphic HEMT technology for low-noise applications

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.

35 nm metamorphic HEMT MMIC technology

A metamorphic high electron mobility transistor (mHEMT) technology featuring 35 nm gate length has been developed. The optimized MBE grown layer sequence has a channel mobility and a channel electron density as high as 9800 cm2/Vs and 6.1times1012 cm-2, respectively. To enable a maximum extrinsic transconductance gm, max of 2500 mS/mm the source resistance has been reduced to 0.1 Omegamiddotmm. An ft of 515 GHz was achieved for a 2 times 10 mum device. Based on this advanced 35 nm mHEMT technology very compact single-stage H-band amplifiers circuits have been realized demonstrating a high small-signal gain of more than 7 dB at 270 GHz.

A Vector Corrected High Power On-Wafer Measurement System with a Frequency Range for the Higher Harmomcs up to 40 GHz

A high power on-wafer measurement system based on the new microwave transition analyzer (MTA) HP 71500A has been developed for the complete characterization of the large signal behavior of transistors. One key feature of the MTA based measurement system is that during power sweeps the harmonic behavior, up to 40 GHz, can be measured. To improve the accuracy of power measurements the vector measurement capability of the MTA is also utilized to allow full vector calibration of the measurement system. In addition, this vector measurement feature allows both the input reflection and the transmission coefficients of a device under test (DUT) to be measured as a function of frequency and input power. The input and output voltage waveforms at the transistor terminals are also calculated from the measurement data. This improved capability is possible since the vector calibrated measurement system allows both the measurement of the fundamental and the higher harmonics with respect to magnitude and phase.

Design and characterization of high performance 60 GHz pseudomorphic MODFET LNAs in CPW-technology based on accurate S-parameter and noise models

An accurate database for active and passive MMIC components valid up to millimeter-wave frequencies has been established. The CAE models for the transistors and the passive CPW-components; which include the coplanar T-junction, are derived from on-wafer S-parameter measurements up to 63 GHz. For noise modeling of the MODFETs up to millimeter-wave frequencies, an approach based on the temperature noise model reported by M.W. Pospiezalski (1989) has been used. The parameter T/sub d/, which is required for the temperature model, is extracted from on-wafer noise parameter measurements up to 18 GHz. Using this database, the authors have designed and fabricated low-noise V-band two-stage amplifiers, using pseudomorphic MODFETs on a GaAs substrate, which have a performance of 10.5-dB gain and 5.2-dB noise figure at 58.5 GHz. Very good agreement between simulated and measured MMIC gain and noise performance is achieved up to V-band. >

A 300 GHz mHEMT amplifier module

In this paper, we present the development of an H-band (220 – 325 GHz) submillimeter-wave monolithic integrated circuit (S-MMIC) amplifier module for use in next generation active and passive high-resolution imaging systems operating around 300 GHz. Therefore, a variety of compact amplifier circuits has been realized by using an advanced 35 nm InAlAs/InGaAs based depletion-type metamorphic high electron mobility transistor (mHEMT) technology in combination with grounded coplanar waveguide (GCPW) circuit topology. A single-stage cascode design achieved a small-signal gain of 5.6 dB at 300 GHz and a linear gain of more than 5 dB between 258 and 308 GHz. Additionally, a four-stage amplifier S-MMIC based on conventional devices in common-source configuration was realized, demonstrating a maximum gain of 15.6 dB at 276 GHz and a linear gain of more than 12 dB over the frequency range from 264 to 300 GHz. Finally, mounting and packaging of the monolithic amplifier chips into H-band waveguide modules was accomplished with only minor reduction in circuit performance.