Search

We have been developing gallium nitride (GaN) monolithic microwave integrated circuits (MMICs) towards the goal of implementing a single chip transceiver frontend for cloud radar arrays at Ka-band. We present our first effort design, fabrication and test cycle implementation of GaN power amplifiers (PAs), low noise amplifiers (LNAs), driver amplifier, single-pole-double and triple throw switches, and voltage controlled attenuator. These components are necessary for implementing a transceiver unit cell concept with digital calibration capabilities to enable scalable array sizes for radar and radiometry.

We are developing Ka-band gallium nitride (GaN) monolithic microwave integrated circuits (MMICs) for a compact transceiver frontend. We present the design, fabrication and test results of a GaN power amplifier (PA), low noise amplifier (LNA), and single-pole-double-throw (SPDT) switch. These components are necessary for implementing a radar transceiver unit cell concept with digital calibration capabilities for future cloud radar arrays.

We report a new result of a packaged low noise amplifier (LNA) module with wide bandwidth of 5 to 35 GHz and low noise temperature performance of 10 -18 K, while operated at 10 K ambient. The LNA used 3-stages of sub-50 nm gate length, 100% indium channel content indium phosphide (InP) high electron mobility transistors (HEMTs). Wideband cryogenic LNAs are important for future radio astronomy observatories. To our knowledge these results represent the lowest noise achieved in a wideband amplifier from 5–35 GHz.

Millimeter and submillimeter indium phosphide (InP) microwave monolithic integrated circuits (MMICs) are increasingly used in applications spanning Earth science, astrophysics, and defense. In this paper, we characterize direct detection and heterodyne gain fluctuations of 35-, 30-, and 25-nm gate-length InP MMIC low-noise amplifiers (LNAs) designed for the 200–670-GHz frequency range. Of the twelve MMIC LNAs, five pairs have also been measured in multistage or cascaded configuration. In direct detection mode, the MMICs room temperature (RT) 1/ f noise spectrum and responsivity were measured. From these the power spectral density, the noise equivalent temperature difference (NETD), equivalent system noise temperature (T $^{DD}_{\rm sys}$ ), and low-frequency normalized gain fluctuations ( $\Delta$ G/G ) are derived. On the same set of MMIC LNAs, using a heterodyne down conversion technique, the Allan variance method is applied to obtain the Allan stability time and normalized 4–8 GHz gain fluctuation noise at both RT and two cryogenic temperatures. We find in the case of 35-, 30-, and 25-nm gate-length InP MMIC LNAs that the derived direct detection and heterodyne gain stability is highly process dependent with only a secondary dependence on gate periphery, the number of gate fingers, and/or gain stages. This observation confirms the underlying solid-state physics understanding that gain fluctuation noise is the result of a temporal distribution of the generation and recombination of electron free carriers due to lattice defects and surface impurities. Upon cooling below $\sim$ 66 K, it is observed that on average gain fluctuations increase by $\gtrsim$ 2.2 $\times$ and the Allan stability time decreases by $\sim$ 2.5 $\times$ . The presented measurement results compare favorably to the ALMA system gain specification of $\Delta$ G/G $\le$ 1.4E $-$ 4 from 0.05 $-$ 100 s, and offers guidance for application of InP LNAs for RT and cryogenic direct detection and heterodyne systems.

In this paper, we report on a new 6-way MMIC power combiner amplifier utilizing cavity modes. The combiner is designed around a square cavity operating in the TM320 electromagnetic mode. Such a configuration produces a total of 6 lobes of maximum field intensity inside the cavity. By placing probes (attached to MMIC amplifier chips) in alignment with the points of maximum field strength, a highly compact power combiner can be achieved. We illustrate this concept using a set of 1 Watt W-band GaN MMIC chips, placed in layered copper sheets and oriented so the MMICs line up with the regions of maximum field strength. A 6-way power combiner was built and was able to deliver 5.5 Watts of output power and 13.4% PAE using a miniature package.

We have implemented a single wideband receiver package that could cover the 8 to 48 GHz frequency range of the ngVLA. The current JVLA covers this frequency range employing five distinct receiver packages. We estimate that reducing the number of receiving systems required to cover the full frequency range should reduce operating costs. The receiver package we developed consists of a quad-ridge feed horn, low-noise amplifiers (LNA), and a down-converter to analog intermediate frequencies. Both the feedhorn and the LNA are cryogenically cooled. On the LNA front we pursued two 8–48 GHz MMIC designs, the first using 70-nm gallium arsenide, metamorphic high-electron-mobility-transistors (HEMT), and the second using 35-nm indium phosphide HEMTs. In this paper, we report the measured gain and noise temperatures of these LNAs.

In this paper, we describe a miniature power-combiner for monolithic millimeter-wave integrated circuit (MMIC) chips using spatial power-combining with cavity modes. We have designed GaN MMIC power amplifier chips for 94 GHz, and illustrate the concept of the W-Band Spatial Power Combining Amplifier (WSPCA). Using 1 Watt, 94 GHz MMIC chips in a two-way cavity mode combiner, we were able to achieve 2 Watts of output power with 9 dB gain and 15 % PAE. This technique could be extended to high power MMICs and larger numbers of chips to achieve higher output power in a compact size. Current applications include earth science radar, and may be extended to other applications requiring wider bandwidth.

NASA planetary missions involve communications between a central orbiter and a number of lander or daughter ships. Given this scenario, large bandwidth data links with compact topologies are required. In this investigation, a photonic-based-transmission link is examined in the extremely high frequency (EHF) regime to scale wireless bandwidth communications given the low power constraints of a system in space. This novel multi-wavelength photonic wireless terahertz wave system incorporates RF transmission up to several hundred GHz and utilizes state-of-the-art low noise receivers for detection.

We have developed gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) amplifiers that span different frequency ranges from Q-band (33–50 GHz) into G-band (140–220 GHz). We have designed, fabricated and tested a broadband amplifier with more than 11 dB of gain from 38 GHz to at least 110 GHz, and a broadband amplifier with gain across all of F-band (90–140 GHz) with peak gain of 18.9 dB and noise figure of 7.4 dB at 120 GHz. In G-band we have developed an amplifier with 8.7 dB small-signal gain at 149 GHz, and when two such amplifiers were placed in series, large signal power measurements gave 18.2 dBm of output RF power and 10 dB gain at 147 GHz. These results demonstrate 0.15 μm gate length GaN HEMTs are applicable for amplifiers through F-band and into G-band.

In this paper we report ultra-low-noise amplifier modules and amplifier module chains for V-band (50-75 GHz). The amplifier chips were fabricated in Northrop Grumman Corporation's (NGC) 35-nm InP HEMT technology and packaged in WR15 waveguide housings utilizing alumina E-plane waveguide probes. The amplifier modules achieve 18 to 27 K noise temperatures from 50 to 75 GHz when cryogenically cooled to 21 K. When measured through a mylar vacuum window, a cascade of two amplifier modules achieves a receiver noise temperature of 18.5 K at 58 GHz. A second chain has a measured receiver noise temperature between 20 to 28 K for the whole V-band. To the best of authors' knowledge, these are the lowest LNA noise temperatures for V-Band reported to date.

Existing spaceborne radiometer receivers, particularly below 40GHz, have typically utilized analog direct detection, but recently have been pushing toward heterodyne systems with digital signal processing to deal with the problem of radio frequency interference (RFI). But, radar and radiometer receivers have yet to be integrated in an optimized manner for spaceborne systems. Fast sampling analog-to-digital converters (ADCs) have been evolving to where we can consider in the 2025 time frame digitizing broad IF signals containing the desired radar signal, natural brightness emission and extraneous man-made RF signals (e.g. RFI) which can then be distributed and processed by radar and radiometer specific digital processors. In this way, a common RF front-end architecture can interface with an agile reconfigurable backend and can be used across several systems (e.g. small, large class sensors). In this study, we designed and demonstrated a multi-purpose receiver that can serve both the needs for the radar and radiometer, first focusing on Ka-band.

Indium Phosphide MMIC LNAs are enabling new capabilities in instrument development. The development of arrays of hundreds of cryogenically-cooled millimeter wave receivers has previously been challenging, but is now achievable with highly repeatable MMIC processes and advances in cryogenic on-wafer testing of LNAs. We have developed InP HEMT LNA MMICs for the 67–90 GHz frequency band that is the last missing receiver system from the ALMA. These MMICs provided average performance of less than 22.5 K noise temperature over the frequency band and minimum noise temperature of 17.5 K at 72 GHz. These LNAs achieve NT=220K (NF=2.4dB) at 90 GHz for Earth remote sensing instrument on Sentinel-6. Our HRMR (High Resolution Microwave Radiometer) achieves NEDT < 0.05K enabling Sentinel-6 to measure coastal ocean topography at 3 km resolution with better than 1 cm accuracy.

The North America Array (NAA), also known as the next-generation Very Large Array (ngVLA), is a concept for a radio astronomical interferometric array operating in the frequency range 1.2 GHz to 116 GHz and designed to provide substantial improvements in sensitivity, angular resolution, and frequency coverage while reducing operational costs compared to the current Jansky Very Large Array (JVLA). At JPL, we are designing a single receiver package designed to operate across the 8 to 48 GHz frequency range, in contrast to the current JVLA, which covers this frequency range with five receiver packages. Reducing the number of receiving systems required to cover the full frequency range would reduce operating costs. We are developing a prototype integrated feed-receiver package with a system noise temperature that meets the requirements of the ngVLA/NAA primary science programs, with a design that meets the requirement of low long-term operational costs. The receiver package being developed at JPL consists of a feed horn, low-noise amplifier (LNA), and down-converters to analog intermediate frequencies. We report on the status of this receiver package development.

In this letter we report an ultra-low-noise amplifier module chain in the WR4 frequency range. The amplifier chips were fabricated in a 35 nm InP HEMT technology and packaged in waveguide housings utilizing quartz E-plane waveguide probes. When cryogenically cooled to 22 K and measured through a mylar vacuum window, the amplifier module chain achieves a receiver noise temperature of 87 K at 228 GHz and less than a 100 K noise temperature from 217 to 236 GHz. The LNA modules have 21–31 dB gain and the power dissipation is 12.4–15.8 mW. To the best of authors' knowledge, these are the lowest LNA noise temperatures at these frequencies reported to date.

In this work, we describe monolithic millimeter-wave integrated circuit (MMIC) Low Noise Amplifier (LNA) and mixer designs for U-Band, also known as the WR19 waveguide band (40–60 GHz). The LNAs were fabricated in NGC's 35 nm InP HEMT MMIC process. The MMICs were packaged in WR19 waveguide housings and tested for noise, both at room temperature and cryogenically. We present the results, including a comparison to the state-of-the-art, and discuss applications for amplifiers in this frequency range. To date, these are the first cryogenic 35 nm InP MMIC results covering the 40–60 GHz range. We achieved a noise temperature less than 30 K over the 40–60 GHz range, when the amplifiers were cryogenically cooled. These results are comparable with other results in the literature, and we believe are the lowest reported for MMICs in the 50–60 GHz range.

We have developed V-Band (50–75 GHz) monolithic millimeter-wave integrated circuit (MMIC) low noise amplifiers using NGC's 35 nm InP HEMT technology. The MMIC LNAs exhibit noise temperatures of 150–270K over the full waveguide band. Subharmonic MMIC mixers were also developed using United Monolithic Semiconductor's GaAs Schottky diode process, and cover V-band with 15–21 dB conversion loss. These components form the front end of receivers that could be used for radio astronomy. While much of V-Band is opaque to the atmosphere, a future space probe to map the intensity of carbon monoxide (CO) in V-band would help astronomers understand the early universe.

This paper presents a 90–100 GHz heterodyne radiometer module based on a CMOS receiver system-on-chip (SoC). The SoC contains a frequency synthesizer, downconverter, RF&IF amplification, as well as a wide range of auto-leveling and calibration, and LO stabilization functions. To provide low-noise operation the CMOS SoC is packaged within a waveguide block and mated with an InP MMIC based LNA pre-amplifier. The complete module delivers noise performance below 400°K and is capable of less than 0.5K NEΔT with an integration time of 50 ms. The entire radiometer instrument consumes 257mW of power and weighs only 334 grams.

Due to copyright restrictions, the access to the full text of this article is only available via subscription. In this paper we discuss the design of low-noise amplifiers (LNAs) for both cryogenic and room-temperature operation in general and take the stability and linearity of the amplifiers into special consideration. Oscillations that can occur within a multi-finger transistor are studied and verified with simulations and measurements. To overcome the stability problem related to the multi-finger transistor design approach a parallel two-finger unit transistor monolithic microwave integrated circuit LNA design technique, which enables the design of wideband and high-linearity LNAs with very stable, predictable, and repeatable operation, is proposed. The feasibility of the proposed design technique is proved by demonstrating a three-stage LNA packaged in a WR10 waveguide housing and fabricated using a 35-nm InP HEMT technology that achieves more than a 20-dB gain from 75 to 116 GHz and 26-33-K noise temperature from 85 to 116 GHz when cryogenically cooled to 27 K. Jet Propulsion Laboratory, California Institute of Technology ; Oak Ridge Associated Universities under NASA Postdoctoral Program (NPP) ; Academy of Finland ; Alfred Kordel Foundation ; National Aeronautics and Space Administration

In this work, we describe new miniaturized low noise amplifier modules which we developed for incorporation in small-scale satellites or Cubesats, and which exhibit similar or better performance compared to previously reported LNAs in the literature. We have targeted the WR4 (170–260 GHz) and WR3 (220–325 GHz) waveguide bands for the module development. The modules include two different methods of E-plane probes which have been developed for low loss, and stability at high frequencies. MMIC LNAs were also developed for these frequency ranges and fabricated in Northrop Grumman Corporation's 35 nm InP HEMT technology, and we have experimentally verified that noise performance is lower than reported in prior work. The best results include a miniature LNA module with 550K noise at 224 GHz, and a wideband LNA module with 15 dB gain from 230–280 GHz.

We report on the development of W-band (75–110 GHz) heterodyne receiver technology for large-format astronomical arrays. The receiver system is designed to be both mass producible, so that the designs could be scaled to thousands of receiver elements, and modular. Most of the receiver functionality is integrated into compact monolithic microwave integrated circuit (MMIC) amplifier-based multichip modules. The MMIC modules include a chain of InP MMIC low-noise amplifiers, coupled-line bandpass filters, and sub-harmonic Schottky diode mixers. The receiver signals will be routed to and from the MMIC modules on a multilayer high-frequency laminate, which includes splitters, amplifiers, and frequency triplers. A prototype MMIC module has exhibited a band-averaged noise temperature of 41 K from 82 to 100 GHz and a gain of 29 dB at 15 K, which is the state-of-the-art for heterodyne multichip modules.

We report cryogenic noise temperature and gain measurements of a prototype heterodyne receiver module designed to operate in the atmospheric window centered on 150 GHz. The module utilizes monolithic microwave integrated circuit (MMIC) InP high electron mobility transistor (HEMT) amplifiers, a second harmonic mixer, and bandpass filters. Swept local oscillator (LO) measurements show an average gain of 22 dB and an average noise temperature of 87 K over a 40 GHz band from 140 to 180 GHz when the module is cooled to 22 K. A spot noise temperature of 58 K was measured at 166 GHz and is a record for cryogenic noise from HEMT amplifiers at this frequency. Intermediate frequency (IF) sweep measurements show a 20 GHz IF band with less than 94 K receiver noise temperature for a fixed LO of 83 GHz. The compact housing features a split-block design that facilitates quick assembly and a condensed arrangement of the MMIC components and bias circuitry. DC feedthroughs and nano-miniature connectors also contribute to the compact design, so that the dimensions of the moduleare approximately 2.5 cm per side.

We report on two-port on-wafer vector network analyzer measurements in the 325-508 GHz frequency band. Measurements are made with prototype GGB Industries Inc. WR2.2 (325-500 GHz) coplanar waveguide probes and OML Inc. WR2.2 frequency extenders. New probe performance data and characteristics of probe tip calibration using a Thru-Reflect-Line procedure are discussed. Probe S-parameter measurements indicate insertion loss per probe of 5.0 to 9.1 dB in the WR2.2 band. Calibrated dynamic range of about 30 dB or better for insertion and return loss measurement across the band is achieved. These new results for the prototype WR2.2 probes, the calibration procedure, observed errors, and results of on-wafer amplifier measurements are presented.

We present an overview of solid-state integrated circuit amplifiers approaching terahertz frequencies based on the latest device technologies which have emerged in the past several years. Highlights include the best reported data from heterojunction bipolar transistor (HBT) circuits, high electron mobility transistor (HEMT) circuits, and metamorphic HEMT (mHEMT) amplifier circuits. We discuss packaging techniques for the various technologies in waveguide modules and describe the best reported noise figures measured in these technologies. A consequence of THz transistors, namely ultra-low-noise at cryogenic temperatures, will be explored and results presented. We also present a short review of power amplifier technologies for the THz regime. Finally, we discuss emerging materials for THz amplifiers into the next decade.

In this paper, we demonstrate a packaged sub-millimeter wave solid-state power amplifier (SSPA). The SSPA is implemented in coplanar waveguide (CPW) and uses an advanced high fMAX InP HEMT transistor with a sub 50-nm gate. A monolithically integrated CPW dipole-to-waveguide transition eliminates the need for wirebonding and additional substrates. On-chip compact tandem couplers are used for power combining. The amplifier demonstrates 15-dB small-signal gain at 340 GHz. Peak saturated output power of 10 mW at 338 GHz is obtained at the waveguide flange out-put for the SSPA module.

A low Terahertz (324 GHz) frequency generator is realized in 90 nm CMOS by linearly superimposing quadruple (N=4) phase shifted fundamental signals at one fourth of the output frequency (81 GHz). The developed technique minimizes the fundamental, second and third order harmonics without extra filtering and results in a high fundamental-to-4 th harmonic signal conversion ratio of 0.17 or -15.4 dB. The demonstrated prototype produces a calibrated -46 dBm output power when biased at 1 V and 12 mA with 4 GHz tuning range and extrapolated phase noise of -91 dBc/Hz at 10 MHz frequency offset. The linear superposition (LS) technique can be generalized for all even number cases (N=2k, where k=1,2,3,4,...,n) with different tradeoffs in output power and frequency. As CMOS continues to scale, we anticipate the LS N=4 VCO to generate signals beyond 2 Terahertz by using 22 nm CMOS and produce output power up to -1.5 dBm with 1.7% power added efficiency with an LS VCO + Class-B Power Amplifier cascaded circuit architecture.

In this paper, we report on the first demonstration of monolithically integrated waveguide transitions in a submillimeter-wave monolithic integrated circuit (S-MMIC) amplifier module. We designed the module for a targeted frequency range of 300-350 GHz, using WR2.2 for the input and output waveguides. The waveguide module utilizes radial -plane transitions from S-MMIC to waveguide. We designed back-to-back radial probe transitions separated by thru transmission lines to characterize the module, and have incorporated the radial -plane transitions with an S-MMIC amplifier, fabricated monolithically as a single chip. The chip makes use of an S-MMIC process and amplifier design from the Northrop Grumman Corporation, Redondo Beach, CA, using 35-nm gate-length InP transistors. The integrated module design eliminates the need for wire bonds in the RF signal path, and enables a drop-in approach for minimal assembly. The waveguide module includes a channel design, which optimizes the -plane probe bandwidth to compensate for an S-MMIC width, which is larger than the waveguide dimension, and is compatible with S-MMIC fabrication and design rules. This paper demonstrates for the first time that waveguide-based S-MMIC amplifier modules with integrated waveguide transitions can be successfully operated at submillimeter-wave frequencies.

In this paper, a sub-millimeter-wave HBT oscillator is reported. The oscillator uses a single-emitter 0.3 m15 m InP HBT device with maximum frequency of oscillation greater than 500 GHz. The passive components of the oscillator are realized in a two metal process with benzocyclobutene used as the primary transmission line dielectric. The oscillator is implemented in a common base topology due to its inherent instability. The design includes an on-chip resonator, output matching circuitry, and injection locking port. A free-running frequency of 311.6 GHz has been measured by down-converting the signal. Additionally, injection locking has been successfully demonstrated with up to 17.8 dB of injection-locking gain. This is the first fundamental HBT oscillator operating above 300 GHz.

We present an effort in developing W-band (75–110 GHz) gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) amplifiers for radar arrays. Due to GaN's high electric field breakdown capability and good 2D electron gas mobility in heterostructure field effect transistors, GaN power amplifiers provide best performance for high output power, high efficiency and small MMIC form factor amplifiers at W-band frequencies. GaN low noise amplifiers can also provide large receiver input dynamic range, reduce receiver noise figure and can be more tolerant of input power leakage from the transmitter without the need of protective limiter circuitry. All these, characteristics are crucial for high frequency arrays where design require small circuit spacings, high efficiency to reduce power consumption and heating, and the minimization of circuit components for manufacturability and reliability. We will discuss results of power, driver and low noise amplifiers that we have designed, fabricated and characterized for radar array applications.

In this paper we propose a parallel two-finger unit transistor MMIC low-noise amplifier design technique which enables the design of wideband and high linearity low-noise amplifiers with very stable, predictable, and repeatable operation. We prove the feasibility of the proposed design technique by demonstrating a three-stage LNA packaged in a WR10 waveguide housing and fabricated using a 35-nm InP HEMT technology that achieves more than a 20-dB gain from 75 to 116 GHz and 26–33-K noise temperature from 85 to 116 GHz when cryogenically cooled to 27 K.

We discuss methods for full two-port vector network analyzer measurements in the 218-344- (using WR3) and 356-500-GHz (using WR2.2) frequency bands. Waveguide test sets (WR3 and WR2.2) utilize Oleson Microwave Laboratories Inc. frequency extenders with the Agilent 8510C network analyzer. On-wafer measurements in the 220-325-GHz band are demonstrated with GGB Industries Inc. coplanar-waveguide probes. This paper primarily reviews the performance capabilities of the WR3 test set and introduces initial calibration results of the WR2.2 test set. For WR3, calibration methods are compared, and dynamic range and frequency extender output power data are presented

We report common-base medium power amplifiers designed for G-band (140-220 GHz) and W-band (75-110 GHz) in InP mesa double HBT technology. The common-base topology is preferred over common-emitter and common-collector topologies due to its superior high-frequency maximum stable gain (MSG). Base feed inductance and collector emitter overlap capacitance, however, reduce the common-base MSG. A single-sided collector contact reduces Cce and, hence, improves the MSG. A single-stage common-base tuned amplifier exhibited 7-dB small-signal gain at 176 GHz. This amplifier demonstrated 8.7-dBm output power with 5-dB associated power gain at 172 GHz. A two-stage common-base amplifier exhibited 8.1-dBm output power with 6.3-dB associated power gain at 176 GHz and demonstrated 9.1-dBm saturated output power. Another two-stage common-base amplifier exhibited 11.6-dBm output power with an associated power gain of 4.5 dB at 148 GHz. In the W-band, different designs of single-stage common-base power amplifiers demonstrated saturated output power of 15.1 dBm at 84 GHz and 13.7 dBm at 93 GHz

This paper presents the design and characterization of W-band IQ sub-harmonic MMIC mixers based on the UMS BES Schottky diode process. The mixers were characterized at 300 K and 20 K physical temperature. They are a key component for the compact heterodyne multi-chip modules to be used in the 16-element Argus focal plane array, which will be deployed at the Green Bank Telescope in late 2014. The RF signal is split in quadrature using a Lange coupler, LO is split in-phase using a Wilkinson divider, and an antiparallel diode pair is used for the design of two sub-harmonically pumped mixer cells. The resulting IF outputs from the two cells are I and Q, which can be combined using an off-chip 90 degree hybrid to obtain LSB and USB. Three mixer designs are fabricated using this topology. A conversion loss between 12 to 18 dB is obtained over 80 to 120 GHz of RF for a fixed IF frequency, and over 10 GHz of IF for a fixed LO frequency. These mixers are designed to operate with low LO power without a significant loss in performance.

In this paper, we demonstrate non-destructive cryogenic probing of monolithic microwave integrated circuit (MMIC) amplifiers at W-band and discuss the implications for the development of large-format focal plane arrays for radio astronomy. Using a purpose-built cryogenic probe station to measure S-parameters and noise temperature of MMIC low-noise amplifiers (LNAs), an order of magnitude increase in efficiency can be achieved when compared with measurements on individually packaged amplifiers. The amplifiers are tested non-destructively, which enables selection based on cryogenic noise and gain; this is crucial for the development of highly-integrated miniaturized receivers for focal plane arrays, such as those used for the measurement of the cosmic microwave background (CMB) polarization and future arrays aimed at probing the epoch of reionization (EoR).

We report on the development of Argus, a 16-pixel spectrometer, which will enable fast astronomical imaging over the 85–116 GHz band. Each pixel includes a compact heterodyne receiver module, which integrates two InP MMIC low-noise amplifiers, a coupled-line bandpass filter and a sub-harmonic Schottky diode mixer. The receiver signals are routed to and from the multi-chip MMIC modules with multilayer high frequency printed circuit boards, which includes LO splitters and IF amplifiers. Microstrip lines on flexible circuitry are used to transport signals between temperature stages. The spectrometer frontend is designed to be scalable, so that the array design can be reconfigured for future instruments with hundreds of pixels. Argus is scheduled to be commissioned at the Robert C. Byrd Green Bank Telescope in late 2014. Preliminary data for the first Argus pixels are presented.

In this work, we report on developments toward ultra-low noise amplifier modules for the WR4 frequency range, covering 170-260 GHz. The amplifiers in question utilize 35 nm HEMT transistors on a 50 μm thick InP substrate, and were developed at NGC. While recent work in this frequency band has demonstrated the usefulness and advanced technology of utilizing integrated waveguide transitions fabricated on the high dielectric constant MMIC amplifiers themselves, we present evidence here that more standard, cost effective techniques like merging low-loss quartz probes with short wire bonds can provide excellent noise performance, even at these high frequencies. The amplifiers discussed in this paper demonstrate a record 600K noise (4.8 dB) at 220 GHz and 700K (5.2 dB) noise at 240 GHz.

We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75–115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

The variation of heterojunction bipolar transistor (HBT) bandwidth with scaling is reviewed. High bandwidths are obtained by thinning the base and collector layers, increasing emitter current density, decreasing emitter contact resistivity, and reducing the emitter and collector junction widths. In mesa HBTs, minimum dimensions required for the base contact impose a minimum width for the collector junction, frustrating device scaling. Narrow collector junctions can be obtained by using substrate transfer or collector-undercut processes or, if contact resistivity is greatly reduced, by reducing the width of the base ohmic contacts in a mesa structure. HBTs with submicron collector junctions exhibit extremely high f/sub max/ and high gains in mm-wave ICs. Transferred-substrate HBTs have obtained 21 dB unilateral power gain at 100 GHz. If extrapolated at -20 dB/decade, the power gain cutoff frequency f/sub max/ is 1.1 THz. f/sub max/ will be less than 1 THz if unmodeled electron transport physics produce a >20 dB/decade variation in power gain at frequencies above 110 GHz. Transferred-substrate HBTs have obtained 295 GHz f/sub T/. The substrate transfer process provides microstrip interconnects on a low-/spl epsiv//sub r/ polymer dielectric with a electroplated gold ground plane. Important wiring parasitics, including wiring capacitance, and ground via inductance are substantially reduced. Demonstrated ICs include lumped and distributed amplifiers with bandwidths to 85 GHz and per-stage gain-bandwidth products over 400 GHz, and master-slave latches operating at 75 GHz.

In this letter, a rectangular waveguide to conductor backed-coplanar waveguide electromagnetic transition suitable of operating at sub-millimeter wave frequencies is demonstrated. The dipole based transition is fabricated using InP monolithic microwave integrated circuit technology. The compact transition eliminates wire-bonding problems (return loss and insertion loss) and is suitable for direct integration of sub-millimeter wave monolithic integrated circuits. Measured transition loss of ~1 dB has been achieved in the frequency range of 340 to 380 GHz.

This paper describes a three-stage monolithic amplifier that exhibits a small-signal gain of 30 dB at 140 GHz. The amplifier employs AlInAs/GaInAs/InP high electron mobility transistor devices with 0.1/spl times/150 /spl mu/m/sup 2/ gate periphery, is implemented with coplanar waveguide circuitry fabricated on an InP substrate, and occupies a total area of 2 mm/sup 2/. Gain exceeding 10 dB was measured on-wafer from 129 to 157 GHz. This is the highest reported gain per stage for a transistor amplifier operating at these frequencies.

In this letter, a new power amplifier topology is demonstrated which allows the use of large (120 mum/transistors) at extremely high frequency. This is accomplished by using compact matching networks consisting of coplanar waveguide transmission lines and metal-insulator-metal capacitors to match each of the three amplifier stages. The resulting amplifier achieves a peak gain of 16.5 dB at 260 GHz. Power measurements indicate that the chip achieves >5.9 mW (unsaturated) of output power and 4% power added efficiency at a frequency of 270 GHz, where the output power is limited by the available source drive power. This power level from a single transistor represents a significant improvement at this frequency band.

We present on-wafer power measurements of 35 nm gate length InP HEMT amplifiers at 330 GHz. Various amplifiers are examined. The maximum output power of 1.78 mW is measured from a three stage amplifier. Additional output power may be possible but limited by our input power source level to saturate amplifiers. This result is the highest frequency on-wafer power measurement we are aware of reported to date, and demonstrates the technique we utilize to be a fast method of evaluating power performance of submillimeter wave amplifiers without the need to package devices.