HEMT Circuits Research Articles

A Space Mapping Augmented Compact Model for Uncertainty Quantification of GaN HEMT Devices and Circuits in the Presence of Trap Effects

A Space Mapping Augmented Compact Model for Uncertainty Quantification of GaN HEMT Devices and Circuits in the Presence of Trap Effects

Special issue on GaN HEMT modeling and circuits

International Journal of RF and Microwave Computer-Aided EngineeringVolume 28, Issue 8 e21540 SPECIAL ISSUE: GaN HEMT MODELING AND CIRCUITS Special issue on GaN HEMT modeling and circuits Prof. Wenhua Chen, Prof. Wenhua ChenSearch for more papers by this authorProf. Karun Rawat, Prof. Karun RawatSearch for more papers by this authorDr. Rui Ma, Dr. Rui MaSearch for more papers by this author Prof. Wenhua Chen, Prof. Wenhua ChenSearch for more papers by this authorProf. Karun Rawat, Prof. Karun RawatSearch for more papers by this authorDr. Rui Ma, Dr. Rui MaSearch for more papers by this author First published: 19 September 2018 https://doi.org/10.1002/mmce.21540Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume28, Issue8Special Issue: GaN HEMT Modeling and CircuitsOctober 2018e21540 RelatedInformation

High-Efficiency RF Pulsewidth Modulation of Class-E Power Amplifiers

A new switch-mode power-amplifier (SMPA) topology particularly suitable for energy efficient amplification of RF pulsewidth modulation (RF-PWM) signals is derived. It is analytically shown that high efficiency can be maintained over a wide power dynamic range if the imaginary part of the Class-E load impedance is varied along with the duty cycle (pulsewidth). Using the theory developed, an explicit design procedure is presented that allows practical realization of the proposed topology from the circuit and component specifications. Following the design procedure, and using in-house (Chalmers University, Goteborg, Sweden) SiC varactor diodes to implement the tunable imaginary load impedance, a 2-GHz 10-W peak output power GaN HEMT circuit demonstrator is realized. RF-PWM input signals for characterization of the prototype power amplifier (PA) is generated with a dedicated 65-nm CMOS modulator. The measurements show that a drain efficiency >; 70% can be obtained over an 6.5-dB dynamic range, which verifies the theory presented and demonstrates the feasibility of the proposed PA topology.

An AlGaN/GaN two‐color photodetector based on an AlGaN/GaN/SiC HEMT layer structure

AbstractThe optoelectronic properties of MSM diodes that are based on an AlGaN/GaN HEMT layer system are investigated as function of the applied bias. For low voltages, the two‐dimensional electron gas acts as a barrier for the depletion layer. Therefore, only the upper AlGaN barrier layer contributes to the photocurrent. In the high voltage regime the depletion region penetrates the GaN buffer that adds the spectral responsivity of GaN to the pure AlGaN behaviour in the low voltage regime. The ratio of the responsivities at 350 nm and 300 nm wavelength can be switched from 0.01 at 2.5 V to 0.8 at 4 V bias. This property makes the MSM‐2DEG a candidate for use as two‐color photodetector. Device fabrication uses standard HEMT processing steps, allowing integration in HEMT circuits without the need of sophisticated growth or etching techniques. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

TUNABLE MICROWAVE INTEGRATED CIRCUITS USING BST THIN FILM CAPACITORS WITH DEVICE STRUCTURE OPTIMIZATION

ABSTRACT The mechanism of losses in barium strontium titanate (BST) thin film capacitors is analyzed at the device level. A geometry dependent RF model is used to minimize the electrode loss. Results show the capacitors' RF quality factors can be further optimized through geometry. A tunable filter and a phase shifter are demonstrated using these design techniques. Successful integration of the BST process with GaN HEMT circuits in the form of a 5 GHz GaN HEMT oscillator is presented. BST thin film technology is shown to be useful for the design of frequency agile circuits and reduction of layout areas in various microwave applications.

AlGaN/GaN varactor diode for integration in HEMTcircuits

Fabrication and characterisation of metal-semiconductor-metal (MSM) diodes above an AlGaN/GaN HEMT layer system for varactor applications are reported. Device fabrication uses standard HEMT processing steps, allowing integration in HEMT circuits without the need of sophisticated growth or etching techniques. Capacitance-voltage measurements exhibit CMAX/CMIN ratios up to 100, tunable by the electrode geometry. These results exceed best values for published heterostructure varactor diodes. Fabrication of AlGaN/GaN HEMTs on the same layer system with identical technology prove the potential for monolithic integration.

Millimeter-wave low-noise and high-power metamorphic HEMT amplifiers and devices on GaAs substrates

This paper reports on state of-the-art HEMT devices and circuit results utilizing 32% and 60% indium content InGaAs channel metamorphic technology on GaAs substrates. The 60% In metamorphic HEMT (MHEMT) has achieved an excellent 0.61-dB minimum noise figure with 11.8 dB of associated gain at 26 GHz. Using this MHEMT technology, two and three-stage Ka-band low-noise amplifiers (LNAs) have demonstrated <1.4-dB noise figure with 16 dB of gain and <1.7 with 26 dB of gain, respectively. The 32% In MHEMT device has overcome the <3.5-V drain bias limitation of other MHEMT power devices, showing a power density of 650 mW/mm at 35 GHz, with V/sub ds/=6 V.

Broadband GaAs MESFET and GaN HEMT resistive feedback power amplifiers

We report 0.2 to 6-GHz MMIC power amplifiers with 12-dB gain, over 23-dBm output power, and more than 25% power-added efficiency (PAE) in a GaAs MESFET technology offering 18 GHz f/sub /spl tau// and 12-V breakdown. These circuits have gain-bandwidth products of /spl sim/1.3/spl middot/f/sub /spl tau// and are more efficient than distributed power amplifiers. A first demonstration of similar circuits in GaN/AlGaN HEMT technology yielded 11-dB gain, 0.2 to 7.5-GHz bandwidth amplifiers with over 31.5-dBm output power and up to 15% PAE. With improved devices and models we expect significantly higher power from the GaN HEMT circuits.

New model extraction for predicting distortion in HEMT and MESFET circuits

A new method is presented for extracting Taylor series coefficients directly from IM measurements for modeling IM distortion in HEMT and MESFET circuits. It is based on an improved model that uses better simplifying assumptions. The method gives a substantially more accurate characterization, especially in the saturation region, required for amplifier designs.

Fully passivated W-band InAlAs/InGaAs/InP monolithic low noise amplifiers

The development of W-band monolithic low noise amplifiers (LNAs) using a fully passivated 0.1 µm pseudomorphic InAlAs/InGaAs/InP low noise HEMT technology is presented. Both wafer passivation and stabilisation bakes have been introduced, for the first time, to the InP HEMT MMIC process to make it more suitable for production. A three-stage single-ended 94 GHz monolithic LNA shows a measured noise figure of 3.3 dB and 20 dB associated gain. A measured noise figure of 2.3 dB is achieved for a single-stage MMIC LNA at 94 GHz. These results represent state-of-the-art performance of HEMT MMIC LNAs at this frequency. The effects due to SiN passivation for both HEMT device and circuit performance are also addressed.

An 18-34-GHz dynamic frequency divider based on 0.2- mu m AlGaAs/GaAs/AlGaAs quantum-well transistors

The design and performance of a dynamic frequency divider was presented. This digital IC demonstrates the ability of the authors' AlGaAs/GaAs/AlGaAs quantum-well FETs with gate lengths of 0.2 mu m. Stable operation was achieved in the frequency range from 18 GHz up to 34 GHz with a power consumption of 250 mW. To the authors' knowledge, this is the best result ever reported for HEMT circuits, and is similar to the frequency limit achieved by use of AlGaAs/GaAs HBTs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Yield sensitivity of HEMT circuits to process parameter variations

The authors summarize the use of a graphical tool, yield factor histograms, to study the yield sensitivity of HEMT circuits to process parameter variations. A computer program called SPICENTER is used to incorporate the HEMT statistical physical model with a SPICE circuit model and then to generate the yield factor histograms and yield sensitivities as functions of the process parameters. The authors present the application of these tools to digital and microwave circuits. Two example HEMT circuits, a two-input NOR gate and an inverter chain, illustrate the concepts. Yield sensitivity is presented as yield percent change per parameter percent change. >

Quasi-optical HEMT and MESFET self-oscillating mixers

Planar quasi-optical receivers that compactly integrate a coupled slot antenna and a HEMT or MESFET balanced self-oscillating mixer and on the same substrate for applications in microwave and millimeter-wave receiver arrays are discussed. Both the HEMT and the MESFET circuit are designed and demonstrated at X-band. The HEMT circuit exhibits an isotropic conversion gain of 4.5 dB and a noise figure of 6.5 dB. The isotropic conversion gain of the HEMT circuit is 7.5 dB higher than the mixer diode circuit previously reported.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>