Showing papers by "Oliver Ambacher published in 2014"

Wireless sub-THz communication system with high data rate enabled by RF photonics and active MMIC technology

Abstract: In communications, the frequency range 0.1–30 THz is essentially terra incognita. Recently, research has focused on this terahertz gap, because the high carrier frequencies promise unprecedented channel capacities1. Indeed, data rates of 100 Gbit s were predicted2 for 2015. Here, we present, for the first time, a single-input and single-output wireless communication system at 237.5 GHz for transmitting data over 20 m at a data rate of 100 Gbit s. This breakthrough results from combining terahertz photonics and electronics, whereby a narrow-band terahertz carrier is photonically generated by mixing comb lines of a mode-locked laser in a uni-travellingcarrier photodiode. The uni-travelling-carrier photodiode output is then radiated over a beam-focusing antenna. The signal is received by a millimetre-wave monolithic integrated circuit comprising novel terahertz mixers and amplifiers. We believe that this approach provides a path to scale wireless communications to Tbit s rates over distances of >1 km. Data rates in both fibre-optic and wireless communications have been increasing exponentially over recent decades. For the upcoming decade this trend seems to be unbroken, at least as far as fibreoptic communications is concerned. In wireless communications, however, the spectral resources are extremely limited because of the heavy use of today’s conventional frequency range up to 60 GHz. Even with spectrally highly efficient quadrature amplitude modulation (QAM) and the spatial diversity achieved with multipleinput and multiple-output (MIMO) technology, a significant capacity enhancement to multi-gigabit or even terabit wireless transmission requires larger bandwidths, which are only available in the high millimetre-wave and terahertz region. Between 200 and 300 GHz there is a transmission window with low atmospheric losses3. In contrast to free-space optical links, millimetre-wave or terahertz transmission is much less affected by adverse weather conditions like rain and fog4,5. Here, we present for the first time a single-input single-output (SISO) wireless 100 Gbit s link with a carrier frequency of 237.5 GHz. By combining state-of-the-art terahertz photonics and electronics and by utilizing the large frequency range in the terahertz window between 200 and 300 GHz, we realize a wireless 100 Gbit s link with SISO technology, that is, a link with one transmit antenna and one receive antenna. To date, 100 Gbit s wireless links have only been demonstrated at lower carrier frequencies around 100 GHz (refs 6–8) over a wireless distance of 1 m, with a bit error ratio (BER) of 1 × 10. Because of the limited bandwidth, these systems relied on optical polarization multiplexing and spatial MIMO with more than one wireless transmitter and receiver. Here, a 100 Gbit s wireless transmission capacity is achieved without resorting to MIMO technology. We envisage various applications1,9,10 for such a high-capacity wireless link (Fig. 1). If an end-to-end fibre connection is absent and the deployment of a new fibre link is not economical, as might be the case in difficult-to-access terrains and certain rural areas (last mile problem), or if an already existing fibre connection fails, a permanent or ad hoc wireless connection could help. Furthermore, we anticipate indoor applications, such as highspeed wireless data transfers between mobile terminals and desktop computers. Figure 1 presents a schematic of our 100 Gbit s wireless experiment embedded into an application scenario where an obstacle, here a broad river, is bridged by the wireless link. We first discuss the general system concept, and then provide further details. For the transmitter (Tx) we use a terahertz photonics technology set-up (Fig. 1). We generate exceptionally pure and stable terahertz carriers by heterodyning frequency-locked laser lines11. A control unit contains a single mode-locked laser (MLL), selects the appropriate frequency-locked comb lines, and modulates data on the carrier lines. An optical fibre transmits the modulated carriers together with an unmodulated comb line, which acts as a remote local oscillator (LO), to a remote uni-travelling-carrier photodiode (UTC-PD). By photomixing the LO and the modulated carriers, radiofrequency signals are generated. Optical heterodyning has already been used in earlier works to implement multi-gigabit wireless systems in the 60 GHz band12–14, in the W-band (75–110 GHz, refs 6–8,15,16), at 120 GHz (refs 17,18) and at carrier frequencies beyond 200 GHz (refs 19,20). For the electronic in-phase/quadrature (IQ) receiver (Rx), we use a custom-developed, active millimetre-wave monolithic integrated circuit (MMIC) with a radiofrequency bandwidth of 35 GHz (refs 21,22). This is, to the best of our knowledge, the first active broadband IQ mixer at 237.5 GHz. The Rx comprises a low-noise amplifier (LNA) and a subharmonic downconversion IQ mixer, and is realized in a metamorphic high electron mobility transistor (mHEMT) technology (Supplementary Section S5) featuring a gate length of 35 nm and a cutoff frequency of more than 900 GHz (refs 23,24). The complex data are directly downconverted to the baseband and separated into I and Q signals. Previous works6–8 in the W-band have illustrated the importance of a high carrier frequency. However, to date, no direct downconversion to baseband has been used due to a lack of IQ mixers covering the full W-band. For carrier frequencies beyond 110 GHz (refs 17–20), simple on–off keying modulation and envelope

A 600 GHz low-noise amplifier module

Abstract: A compact WR-1.5 (500-750 GHz) low-noise amplifier (LNA) circuit has been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 20 nm metamorphic high electron mobility transistors (mHEMTs). The realized six-stage LNA TMIC achieved a maximum gain of 15.4 dB at 576 GHz and more than 10 dB in the frequency range from 555 to 619 GHz. For low-loss packaging of the circuit, a waveguide-to-microstrip transition has been fabricated on a 20 ¼m thick GaAs substrate, demonstrating an insertion loss of only 1 dB between 500 and 720 GHz. The realized LNA module achieved a small-signal gain of 14.1 dB at 600 GHz and a room temperature (T = 293 K) noise figure of 15 dB at the frequency of operation.

20 nm Metamorphic HEMT technology for terahertz monolithic integrated circuits

Abstract: A metamorphic high electron mobility transistor (mHEMT) technology with 20 nm gate length for manufacturing of terahertz monolithic integrated circuits (TMICs) is presented. The passive elements include up to four interconnection metallization layers separated by low-k dielectrics (BCB), SiN and air which can be used to realize front side signal lines. Shielding the substrate from the electromagnetic field on the wafer front side eliminates the need of a costly back side process including wafer thinning, through substrate via etching and back side metallization. The semiconductor heterostructure of the mHEMT comprises a strained pure InAs channel with high electron mobility and high electron density for proper device scaling. The realized mHEMTs achieve a source resistance rS of 0.12 Ωmm which is required to minimize resistive losses in combination with an extrinsic maximum transconductance gm_max of 2850 mS/mm. Elaborated on wafer calibration procedures and optimized test transistor layouts were used to improve the precision of the S-parameter measurements up to a frequency of 450 GHz which than could be used for model extraction. The presented 20 nm mHEMT technology was employed for the design of a compact eight stage low-noise amplifier (LNA) using miniaturized microstrip lines on BCB. The measured small signal gain of the LNA exceeds 15 dB from 500-635 GHz.

Improved AlGaN p-i-n Photodetectors for Monitoring of Ultraviolet Radiation

Abstract: Improved aluminum-gallium-nitride (Al x Ga 1-x N) p-i-n photodetectors with different active regions are reported, designed for the measurement of UV-A (315 to 380 nm), UV-B (280 to 315 nm), and UV-C (<; 280 nm) radiation. The spectral responsivity of Al x Ga 1-x N photodetectors can be tailored by bandgap engineering of the Al x Ga 1-x N layers and integration of filter layers. Intrinsically visible-blind p-i-n photodetectors are measured on-wafer and packaged in TO-18 headers. Photocurrent measurements in photovoltaic mode result in responsivity values of up to 0.21 A/W for UV-A (EQE = 70%), 0.14 A/W for UV-B (EQE = 56%), and 0.11 A/W for UV-C (EQE = 57%), respectively. The room temperature dark current density values as low as 30 pA/cm 2 at a reverse bias of -3 V yield a specific detectivity of more than 4 × 10 14 cm Hz 0.5 /W. Response time data of the p-i-n photodiodes indicate a rise time of 1.7 ns and a fall time (1/e) of 4.5 ns. Long-term stability tests over 1000 h at an irradiance of 5 W/cm 2 demonstrate the potential of these photodetectors for demanding applications such as the continuous monitoring of high irradiance ultraviolet light sources.

Watt-level non-uniform distributed 6–37 GHz power amplifier MMIC with dual-gate driver stage in GaN technology

Abstract: This paper reports on a wide bandwidth monolithic power amplifier suitable for wide bandwidth applications up to the Ka-band such as electronic warfare systems. The MMIC is based on a 100nm AlGaN/GaN T-gate HEMT microstrip transmission line technology with an f T > 80 GHz. The designed and fabricated amplifier uses the non-uniform distributed power amplifier topology and covers a frequency range from 6GHz to 37 GHz, whereas the lower band edge is limited by the on-chip DC bias network. The MMIC is a dual-stage topology which employs dual-gate HEMTs in the driver stage in order to boost the gain of the overall amplifier. The measured S 21 is (17 ± 1) dB. This is a significant increase of 3 dB as compared to a driver stage using standard common-source HEMTs. An output power well beyond 1W over the entire frequency range is obtained. To the authors' knowledge, this is the highest output power achieved by a distributed amplifier at this frequency range.

A Broadband 220-320 GHz Medium Power Amplifier Module

Abstract: In this paper, we present the development of an ultra-broadband H-band (220 - 325 GHz) submillimeter-wave monolithic integrated circuit (S-MMIC) medium power amplifier (MPA) module for use in next generation high-resolution imaging systems and communication links operating around 300 GHz. Therefore, a variety of compact amplifier circuits has been developed 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 three-stage amplifier S-MMIC based on compact cascode devices was realized, demonstrating a maximum gain of 22.2 dB at 294 GHz and a small-signal gain of more than 16 dB over the frequency range from 184 to 312 GHz. Finally, mounting and packaging of the monolithic amplifier chip into a WR-3.4 waveguide module was accomplished with only minor reduction in circuit performance.

Q- and E-band amplifier MMICs for satellite communication

Abstract: This work discusses MMICs for the realization of spaceborn multi-Gigabit satellite communication systems. A broadband low-noise amplifier, based on a 50 nm GaAs mHEMT technology, has been developed for Q-band low-noise receivers. The amplifier shows a small-signal gain of 27.5 dB with a gain flatness of ± 1.2 dB and a noise figure below 2 dB over the entire targeted frequency range between 30 and 50 GHz. For the next generation of E-band transmitter modules, a GaN-based high-power amplifier with a small-signal gain above 15 dB between 70-75 GHz and a saturated output power exceeding 28 dBm at 74 GHz has been developed.

A 92 GHz GaN HEMT voltage-controlled oscillator MMIC

Abstract: In this paper, we report state-of-the-art high frequency performance of a W-band voltage-controlled oscillator (VCO) MMIC realized in a 0.1 μm AlGaN/GaN HEMT technology. The oscillation frequency of the VCO can be tuned between 85.6 and 92.7 GHz, which is a relative tuning bandwidth of 8%. The achieved maximum output power is as high as 10.6 dBm. The phase noise of the VCO varies from -80.2 to -90.2 dBc/Hz at 1 MHz offset from the carrier over the tuning voltage range.

243 GHz low-noise amplifier MMICs and modules based on metamorphic HEMT technology

Abstract: Two compact H-band (220–325 GHz) low-noise millimeter-wave monolithic integrated circuit (MMIC) amplifiers have been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 and 35 nm metamorphic high electron mobility transistors (mHEMTs). For low-loss packaging of the circuits, a set of waveguide-to-microstrip transitions has been realized on 50-μm-thick GaAs substrates demonstrating an insertion loss of <0.5 dB at 243 GHz. By applying the 50 nm gate-length process, a four-stage cascode amplifier module achieved a small-signal gain of 30.6 dB at 243 GHz and more than 28 dB in the bandwidth from 218 to 280 GHz. A second amplifier module, based on the 35-nm mHEMT technology, demonstrated a considerably improved gain of 34.6 dB at 243 GHz and more than 32 dB between 210 and 280 GHz. At the operating frequency, the two broadband low-noise amplifier modules achieved a room temperature noise figure of 5.6 dB (50 nm) and 5.0 dB (35 nm), respectively.

Backside Process Free Broadband Amplifier MMICs at D-Band and H-Band in 20 nm mHEMT Technology

Abstract: High gain amplifier MMICs (monolithic microwave integrated circuits) addressing broadband radar and communication applications at the waveguide bands WR-6 (110 - 170 GHz) and WR-3 (220 - 325 GHz) are presented. All circuits are manufactured in the next generation metamorphic high electron mobility transistor (mHEMT) technology featuring 20 nm gate length and a strained 100% InAs channel. The transistors are encapsulated by 0.3 μm and 1.4 μm thick layers of benzocyclobutene (BCB). The 1.4 μm thick BCB layer is used to form shielded thin-film microstrip (TFMS) lines confined at the front-side of the wafer for implementing matching networks. Substrate thinning and backside processing is not required for the function of the amplifiers. The amplifier for WR-6 operates over the whole waveguide band with an average gain of 28 dB. A gain of more than 24 dB was measured for the MMIC from 215 - 290 GHz. All presented MMICs exceed 30% of gain defined bandwidth.

A low-power W-band receiver MMIC for amplitude modulated wireless communication up to 24 Gbit/s

Abstract: A low-power receiver MMIC for high-speed wireless communication at W-band frequencies using BASK modulation is presented. The MMIC contains a three stage LNA and a zero bias envelope detector as BASK demodulator. The envelope detector utilizes a novel approach with a branchline coupler, targeting broadband performance and improved time domain behavior accordingly. The receiver MMIC is based on a 50 nm InGaAs metamorphic HEMT technology, which also provides integrated Schottky diodes with an optimized diode layout. The receiver is covering the entire W-band for high data rates and an easy adoption of diverse carrier frequencies, likewise. The MMIC exhibits a data rate up to 24 Gbit/s at a carrier frequency of 108 GHz and consumes only 14.4mW at the most with a supply voltage of 0.6 V. This results in an efficiency of 0.6 pJ/bit for the entire receiver MMIC.

Realization of a 30-W highly efficient and linear reconfigurable dual-band power amplifier using the continuous mode approach

Abstract: This paper presents the design methodology and the realization of a highly linear and power-efficient reconfigurable dual-band amplifier based on the continuous/Class-ABJ approach. The Class-ABJ theory allows presenting different reactive solutions on both fundamental and second harmonic terminations compared with the standard Class-AB mode. Despite the various terminations, a constant optimum output performance in terms of power, gain, and efficiency can still be achieved. The output impedances are then translated into frequency thus allowing the realization of broadband power amplifiers (PAs) at high-power level of 30 W. In this work, the Class-ABJ broadband approach will be used for the realization of a reconfigurable dual-band power amplifier operating in the two frequency bands 2.1–2.2 and 2.5–2.6 GHz. Continuous wave (CW) measurements on the realized PA show power and efficiency greater than 17 W and 55% in the two frequency bands with peak values up to 30 W and 63.7%. Indeed, it is shown that such novel modes can be predistorted and therefore the linearity requirement can also be met.

A scalable compact small-signal mHEMT model accounting for distributed effects in sub-millimeter wave and terahertz applications

Abstract: In this paper we utilize a new approach for a small signal model which is scalable from very small to rather large transistors in a wide frequency range from 50 MHz up to 500 GHz. We show that with increasing frequency and decreasing transistor size we need to take into account termination effects at the open ends of the transistor electrodes. This new approach is based on a decomposition of the transistor into multiport sections. These sections are simulated individually by an electromagnetic field solver and then parameterized by compact networks. The model is verified by S-parameter measurements up to 450 GHz.

Planar Zero Bias Schottky Diodes on an InGaAs Metamorphic HEMT MMIC Process

Abstract: In this letter, the realization of planar zero bias Schottky diodes on an InGaAs metamorphic high-electron-mobility transistor (mHEMT) MMIC technology is presented. The aim is to investigate the optimum performance for detector applications in an integrated MMIC solution. Device optimization was performed, by analyzing the voltage responsivity of each single diode variation. Voltage responsivities of up to 18000 V/W at W-band frequencies on an intrinsic diode level were achieved. Furthermore, a detector MMIC centered around 105 GHz was realized with a maximum voltage responsivity of 7700 V/W.

Active harmonic source-/load-pull measurements of AlGaN/GaN HEMTs at X-band frequencies

Abstract: Active harmonic loadpull measurements investigation for a 1-mm AlGaN/GaN HEMT power transistor at X-Band frequencies are in this paper reported. The paper highlights the transistor performances in terms of maximum PAE, POUT and Gain achieved at 8.7 GHz together with the application of a systematic source-/load-pull measurement procedure including wafer-mapping capability. The measurements were carried out using an active harmonic loadpull test system with four control loops. In particular, fundamental and second harmonic “loads” as well as second harmonic “source” terminations have been properly varied and optimized. The 1-mm GaN power device delivered very high efficiency of DE=71.2% and PAE=66.1%, together with high POUT and power gain of 35 dBm (3.2 W) and 11.5 dB, respectively.

Reliability of GaN HEMTs with a 100 nm gate length under DC-stress tests

Abstract: The reliability of AlGaN/GaN HEMTs with a gate length of 100 nm suitable for applications up to W-band frequencies has been investigated by on- and off-state DC-stress tests. The extrapolated life time measured using the constant current stress test exceeds 105 h at a base plate temperature of 125°C. Very promising reliability results have also been found for the current step-stress tests even at the highest stress level of a DC power density of 12 W/mm. During off-state step-stress test the drain current exceeds the gate current indicating the onset of a buffer leakage current at drain voltages above the operation voltage.

High linearity active GaN-HEMT down-converter MMIC for E-band radar applications

Abstract: A down-converter MMIC in 100 nm gate length AlGaN/GaN HEMT technology achieves an input-related 1-dB compression point of 13 dBm at a center frequency of 77 GHz, providing high linearity for radar applications. The single-ended fundamental mixer without preor post-amplification shows 8 dB conversion loss when driven with 13 dBm of LO power within an RF frequency range exceeding 75 to 81 GHz. The high linearity is achieved by operating the GaN transistor as active transconductance mixer, allowing for a high voltage swing of the RF signal even when using a relatively small transistor size as required by the high operating frequency.

Growth model investigation for AlN/Al(Ga)InN interface growth by plasma-assisted molecular beam epitaxy for high electron mobility transistor applications

Abstract: Heterostructures with lattice matched Al(Ga)InN barriers have been widely investigated as alternative to standard AlGaN/GaN based high electron mobility transistor structures for high power applications. Mostly these heterostructures comprise a thin AlN based spacer between GaN channel and lattice matched barrier. One key issue for high quality plasma-assisted molecular beam epitaxy (PA-MBE) of these structures is the control of the AlN–Al(Ga)InN interface since optimal growth conditions for high quality AlN differ significantly from those for growth of indium containing material. In this paper, a detailed analysis and a deduced model of the interface growth is presented. The Al/N ratio during AlN spacer growth is likely to influence the subsequent growth of quaternary Al(Ga)InN. Ideal Al/N ratio leads to high performance heterostructures, while slightly Al-rich conditions lead to the formation of Al residues on the substrate surface, which hinder subsequent epitaxial growth. Al/N ratios below unity lead to the deposition of ternary AlGaN instead of binary AlN spacers and to increased alloy scattering. An insertion of a thin GaN layer between spacer and barrier can hinder the formation of Al residues and leads to improved wafer homogeneity.

Wireless communications on THz carriers takes shape

Abstract: High carrier frequencies in the terahertz range 0.1...30 THz are required for wireless data transmission at line rates at or beyond 100 Gbit/s. Here we demonstrate a system with one to three carriers near 237 GHz for (75...100) Gbit/s single-polarization transmission over distances of (20...40) m. The narrow-band THz carrier is generated by photomixing of highly stable mode-locked laser lines in a uni-travelling-carrier photodiode. The electrical photodiode output is radiated over a lensed horn antenna. Besides a receiving lensed horn antenna, the receiver comprises monolithic integrated circuits with mixers and amplifiers. This synergetic use of THz photonics and electronics (“teratronics”) should be scalable to wireless Tbit/s transmission over 1 km. Such a wireless link could bridge the last mile to a subscriber, or could connect two spatially separated fibre gateways.

Low-power wireless data transmitter MMIC with data rates up to 25 Gbit/s and 9.5mW power consumption using a 113 GHz carrier

Abstract: In this paper a low-power wireless data transmitter MMIC at 113 GHz with data rates up to 25 Gbit/s is presented. The power consumption of the transmitter MMIC is 9.48mW and the output power is about 4.3 dBm. The measured bit error rate is less than 1 × 10 -12 for at least up to 13 Gbit/s. The transmitter is a fully integrated MMIC based on a 50nm InGaAs metamorphic HEMT technology. The circuit consists of a low-power voltage controlled oscillator as signal generator and a low-loss high-speed switch as amplitude modulator, only needing a single-ended data input signal. The whole transmitter MMIC has a size of only 1.25×1mm 2 .

Electroluminescence Investigation of the Lateral Field Distribution in AlGaN/GaN HEMTs for Power Applications

Abstract: The lifetime and stability of AlGaN/GaN heterostructure eld e ect transistors at high power levels can be enhanced by introducing eld plates to reduce electric eld peaks in the gate drain region. Simulations of the electric eld distribution along the channel using the 2D ATLAS software from Silvaco indicate that above a characteristic drain source voltage three spatially separated electric eld peaks appear, one located at the drain-side edge of the gate foot, one at the end of the drain-sided gate eld plate, and one at the end of the source shield eld plate. The close correlation between lateral electric eld and the electroluminescence due to hot electron related intra-band transitions can be very helpful when optimizing the electric eld distribution in high power devices. Electroluminescence microscopy images of devices with gate and source shield eld plate reveal the peaks located at the locations of enhanced electric eld. By studying the voltage dependence of the electroluminescence peaks the in uence of the eld plates on the electric eld distribution in source drain direction can be visualized.

Broadband 1.7–2.8 GHz high-efficiency (58%), high-power (43 dBm) Class-BJ GaN power amplifier including package engineering

Abstract: In this paper a broadband high-efficiency Class-BJ GaN HEMT-PA for wireless communication applications is realized. Influences of packaging and bond wires on the PA performance are investigated in order to demonstrate and use accurate package models. A novel optimization of bond wires for packaged powerbars is therefore performed and, subsequently a fully characterized PA is effectively designed. For the fully assembled PA module, measurement results demonstrated targeted broadband performance reaching approximately 50% operation bandwidth in the frequency range 1.7-2.8 GHz with 52-59% PAE, 58-66% drain efficiency and 43-44.5 dBm delivered output power while maintaining over 10 dB of GT.

Influence of surface roughness on the optical mode profile in GaN-based violet ridge waveguide laser diodes

Abstract: We investigate the influence of the epitaxial layer roughness on the far-field profile of the optical mode in gallium Nitride-based, c-plane ridge waveguide laser diodes. Occasionally, we observe long-range growth instabilities leading to a periodical modulation of the surface. Amplitude and period of this surface roughness is typically on the order of a few 10nm and 20 μm, respectively. Using different characterization techniques, we investigate the influence of the surface roughness on the vertical mode profile along the fast axis in the far-field, in particular the contribution of light scattering at the rough waveguide interfaces, as well as that of substrate modes.

Characterization of AlGaN/GaN-on-Si HFETs in high-power converter applications

Abstract: AlGaN/GaN-on-Si Heterostructure Field-Effect Transistors (HFETs) for power switching are investigated in this paper. A design study for a fast switching environment for power devices is provided including an analysis of the technology, the fabrication, and the performances of large-area AlGaN/GaN-on-Si HFETs. Different power packages and high-current drivers are compared and the results are being discussed. Furthermore the power conversion efficiency is being evaluated for different power- and switching-frequency ranges by means of a converter test board. At 100 kHz efficiencies up to 98.7 % at power levels of up to 1.6 kW could be achieved. At 1 MHz and 1 kW input power an efficiency of 97.1 % was measured.

Excitons and exciton‐phonon coupling in the optical response of GaN

Abstract: We carried out reflectance and spectroscopic ellipsometry measurements of high-purity c -plane epitaxial films of wurtzite GaN in a temperature range 5-840 K. Analysis of the data reveals three main contributions to the dielectric function related to optical transitions involving discrete exciton states, excitonic continuum and exciton-phonon complexes, respectively. The observed contributing mechanisms show different temperature dependence. This behavior is related to specific interactions between optical excitations and thermal LO phonons. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Cryogenic low noise amplifier development for 67–116 GHz

Abstract: Two monolithic microwave integrated circuit low noise amplifiers for 67-116 GHz have been developed using the 50 nm metamorphic high electron mobility transistor technology of Fraunhofer IAF. Both amplifiers have been measured on-wafer at room temperature and one of them additionally in a waveguide module at an ambient temperature of 18 K. The average gain and noise temperature in the band 75-110 GHz are 23 dB and 69 K, respectively, in the latter case.