Ultralow-noise W-band pseudomorphic InGaAs HEMT's

Low-noise planar doped pseudomorphic (PM) InGaAs high-electron-mobility transistors (HEMTs) with a gate length of 0.1 μm for W-band operation are discussed. These devices feature a multiple-finger layout with air bridges interconnecting the sources to reduce gate resistance. The device exhibits a minimum noise figure of 2.5 dB with an associated gain of 4.7 dB at 92.5 GHz. This result demonstrates the feasibility of using PM InGaAs HEMTs for W-band low-noise receivers without the need for using lattice-matched InP HEMTs     

A W-band monolithic downconverter

The design, fabrication, and evaluation of a fully integrated W-band monolithic downconverter based on InGaAs pseudomorphic HEMT technology are presented. The monolithic downconverter consists of a two-stage low-noise amplifier and a single-balanced mixer. The single-balanced mixer has been designed using the HEMT gate Schottky diodes inherent to the process. Measured results of the complete downconverter show conversion gain of 5.5 dB and a double-sideband noise figure of 6.7 dB at 94 GHz. Also presented is the downconverter performance characterized over the -35°C to +65°C temperature range. The downconverter design was a first pass success and has a high circuit yield     

High-performance second-harmonic operation W-band GaAsGunn diodes

High output power performance and DC-to-RF conversion efficiency of second-harmonic-operation W-band (75-110 GHz) GaAs Gunn diodes is reported. Output powers of 96 and 48 mW at 94 and 103 GHz, respectively, with a DC-to-Rf conversion efficiency of 2.7 and 2.3 percent, have been achieved using single-diode GaAs Gunn oscillators. The operation of these diodes requires 2 to 4 W of DC power consumption     

A W-band image-rejection downconverter

The design, fabrication, and evaluation of a W-band image-rejection downconverter based on pseudomorphic InGaAs-GaAs HEMT technology are presented. The image-rejection downconverter consists of a monolithic three-stage low-noise amplifier, a monolithic image-rejection mixer, and a hybrid IF 90° coupler with an IF amplifier. The three-stage amplifier has a measured noise figure of 3.5 dB, with an associated small signal gain of 21 dB at 94 GHz while the image-rejection mixer has a measured conversion loss of 11 dB with +10 dBm LO drive at 94.15 GHz. Measured results of the complete image-rejection downconverter including the hybrid IF 90° coupler and a 10 dB gain amplifier show a conversion gain of more than 18 dB and a noise figure of 4.6 dB at 94.45 GHz     

Multifunction W-band MMIC receiver technology

The development of a W-band (75-110 GHz) monolithic receiver, culminating in a three-chip multifunctional monolithic microwave integrated circuit (MMIC) receiver front-end, is described. The heart of the receiver is a four-channel multiplexer, with each channel possessing its own single balanced mixer and low-noise IF amplifier, all integrated onto a single GaAs chip. Two dual-channel monolithic Gunn oscillators with the drive level and spectral parity to meet system requirements have been developed. The key to the development of the monolithic front-end has been to ensure process compatibility between individual components and the careful partitioning of the chip architecture     

High-performance Ka-band and V-band HEMTlow-noise amplifiers

Quarter-micron-gate-length high-electron-mobility transistors (HEMTs) have exhibited state-of-the-art low-noise performance at millimeter-wave frequencies, with minimum noise figures of 1.2 dB and 32 GHz and 1.8 dB at 60 GHz. At Ka-band, two-stage and three-stage HEMT low-noise amplifiers have demonstrated noise figures of 1.7 and 1.9 dB, respectively, with associated gains of 17.0 and 24.0 dB at 32 GHz. At V-band, two stage and three-stage HEMT amplifiers yielded noise figures of 3.2 and 3.6 dB, respectively, with associated gains of 12.7 and 20.0 dB and 60 GHz. The 1-dB-gain compression point of all the amplifiers is greater than +6 dBm. The results clearly show the potential of short-gate-length HEMTs for high-performance millimeter-wave receiver application     

W-band low-noise InAlAs/InGaAs lattice-matched HEMTs

Very low-noise 0.15-μm gate-length W-band In_0.52 Al_0.48As/In_0.53Ga_0.47As/In _0.52Al_0.48As/InP lattice-matched HEMTs are discussed. A maximum extrinsic transconductance of 1300 mS/mm has been measured for the device. At 18 GHz, a noise figure of 0.3 dB with an associated gain of 17.2 dB was measured. The device also exhibited a minimum noise figure of 1.4 dB with 6.6-dB associated gain at 93 GHz. A maximum available gain of 12.6 dB at 95 GHz, corresponding to a maximum frequency of oscillation, f_max, of 405 GHz (-6-dB/octave extrapolation) in the device was measured. These are the best device results yet reported. These results clearly demonstrate the potential of the InP-based HEMTs for low-noise applications, at least up to 100 GHz     

High-power V-band pseudomorphic InGaAs HEMT

The author's present the DC and RF power performance of planar-doped channel InGaAs high-electron-mobility transistors (HEMTs). The planar-doped channel (PDC) pseudomorphic GaAs HEMT with 400 μm of gate width exhibited an output power of 184 mW, corresponding to 460 mW/mm, with 4.6-dB saturation gain and 25% power-added efficiency at 55 GHz. Although higher power density is possible, the authors have designed the device to operate at less than 500 mW/mm for thermal and reliability reasons. Devices with unit gate finger widths ranging from 30 to 50 μm were fabricated and characterized, with no performance degradation observed from using the longer gate fingers     

Experimental characteristics and performance analysis of monolithicInP-based HEMT mixers at W-band

Experimental characteristics of monolithic InAlAs/InGaAs HEMT mixers are presented together with a theoretical analysis. Experiments at W-band show a maximum conversion gain of 0.9 dB with 2 dBm of LO power level. This is the first demonstration of a monolithic HEMT mixer with conversion gain at W-band. The conversion gain dependence on LO power, RF frequency and gate bias is measured and compared with the theoretical predictions. Good agreement between the theory and experiment could be found     

High-gain W band pseudomorphic InGaAs power HEMTs

The authors have fabricated 0.1-μm T-gate pseudomorphic (PM) InGaAs power high-electron-mobility transistors (HEMTs) with record power and gain performance at 94 GHz. Devices with 40-μm gate peripheries achieved 10.6-mW output power with 7.3-dB gain and 14.3% power-added efficiency (PAE). Devices with 160-μm gate peripheries achieved 62.7-mW output power with 4.0-dB gain and 13.2% PAE. The authors believe the superior performance of these devices is due to the combination of a short 0.1-μm T-gate, high-quality material, optimized device profile, and the reduction in source inductance due to source vias     

A low-current Ku-band GaAs monolithic image rejectiondown-converter

A single-chip image rejection downconverter has been designed, fabricated. and tested for broadcast satellite receivers operating in the 11.7- to 12.2-GHz range. The downconverter consists of an RF low-noise amplifier (LNA), a filter-type image rejection mixer (IRM), and an intermediate frequency amplifier (IFA). It receives 11.7- to 12.2-GHz RF signals and down converts to 1.0- to 1.5-GHz IF signals with an external local oscillator. Since the filter integrated on the downconverter produces an image rejection of more than 30 dB, the downconverter requires no off-chip circuits for the image rejection. A conversion gain of 37±1 dB and a noise figure of less than 3.5 dB have been achieved over the RF frequency range. The current dissipation is only 40 mA, and the chip size is 2.8 mm×2.8 mm×0.45 mm     

A Q-band monolithic balance resistive HEMT mixer usingCPW/slotline balun

A Q-band balanced, resistive high-electron-mobility-transistor (HEMT) mixer has been developed for integration in monolithic millimeter-wave receivers. The mixer consists of two AlGaAs/GaAs HEMTs, a coplanar-waveguide (CPW)-to-slotline local oscillator (LO) balun, and an active IF balun. CPWs are used to eliminate the backside or via-hole process step, which increases the circuit yield and shortens the processing time. The conversion loss of the mixer while downconverting a 42-46-GHz RF to a 2.3-3.2-GHz IF is between 4 and 8 dB using an LO drive of 14 dBm. A 17.5-dBm input two-tone third-order intermodulation intercept point is achieved with an LO drive of 10.5 dBm, while a 5.5-dBm input, 1-dB compression point can be achieved with an LO drive of 14 dBm. This is the first reported monolithic CPW resistive HEMT mixer operating at Q-band frequencies     

Performance analysis of Ku-band VSAT networks

A critical parameter of a very small aperture terminal (VSAT) satellite network, namely the availability of its links, is defined as the percentage of time that information can be transmitted and received with acceptable quality. The information quality is quantified, and the factors that affect it are described. Link unavailability (outage) due to equipment problems and rainfall is discussed. The use of spread-spectrum techniques is considered. A performance analysis example is provided and some conclusions are drawn     

L- and S-band low-noise cryogenic GaAs FETamplifiers

The authors present the results of the construction and testing of three cryogenic low-noise GaAs FET amplifiers, based on a National Radio Astronomy Observatory design, to be used in a detector for the axion, a hypothetical particle. The amplifiers are centered on 1.1 GHz, and 2.4 GHz, have a gain of approximately 30 dB in bandwidths of 300 MHz, 225 MHz, and 310 MHz, and have minimum noise temperatures of 7.8 K, 8 K, and 15 K, respectively     

X-band power AlGaAsInGaAs P-n-p HBTs

AlGaAs/InGaAs P-n-p heterojunction bipolar transistors (HBTs) were fabricated using carbon-doped material grown by nonarsine metal-organic vapor-phase epitaxy (MOVPE). F_max of 39 GHz and f_t of 18 GHz were obtained. Operated in common-base mode, a P-n-p HBT achieved 0.5-W output power with 8-dB gain at 10 GHz; saturated output power was 0.69 W. Results are presented for devices with emitter lengths from 120 to 600 μm     

A monolithic Ka-band 0.25 μm GaAs MESFET transmitterfor high volume production

A monolithic Ka-band transmitter consisting of a voltage-controlled oscillator (VCO) and a power amplifier using 0.25 μm MESFET technology has been developed for high volume production. An output power of 21.5 dBm at 35.4 GHz with a tuning range of 600 MHz has been achieved. Hundreds of these monolithic transmitters have been fabricated, and an RF yield of 40% has ben achieved from the GaAs MMIC pilot line based on the total number of wafers started. The high yield obtained from this high level integration of multifunctional MMIC chips indicates the maturity of the design and processing capability of millimeter-wave (MMW) GaAs MESFET technology     

K-band operation of asymmetric Fabry-Perot modulators

The authors report preliminary high-frequency, small-signal optical measurements of asymmetric multiple-quantum well (MQW) Fabry-Perot electrooptic modulators which indicate that the electrical bandwidth for these devices is about 15 GHz at the onset of saturation, and as high as 21 GHz at low optical intensity-higher than any other measurements published to date. The modulators, 30 μm×30 μm in size, are integrated with on-chip microwave probe pads. The authors detail the fabrication process developed to achieve these high operating frequencies and predict from device models the maximum RC-limited operating frequencies for these devices     

Dual passband dichroic plate for X-band

A need arose in the NASA Deep Space Network, a worldwide tracking system, for a dichroic plate that would be transparent at two desired frequency bands in the X-band region and be totally reflective at S-band. The dual-passband dichroic plate that was developed to meet the technical requirements is a thick metallic plate having an array of periodic round holes filled with Teflon plugs. Test results on an experimental prototype plate indicate that it is technically possible to design a dielectrically filled dichroic plate that meets all of these technical requirements     

High-efficiency Ku-band HBT MMIC power amplifier

A Ku-band monolithic HBT power amplifier was developed using a metal-organic chemical vapor deposition (MOCVD)-grown AlGaAs/GaAs heterojunction bipolar transistor (HBT) operating in common-emitter mode. At a 7.5 V collector bias, the amplifier produced 0.5 W CW output power with 5.0 dB gain and 42% power-added efficiency in the 15-16 GHz band. When operated at a single frequency (15 GHz), 0.66 W CW output power and 5.2 dB of gain were achieved with 43% PAE