A5062493782- Microwave Engineering and Waveguides
- Superconducting and THz Device Technology
- Radio Frequency Integrated Circuit Design
- Gyrotron and Vacuum Electronics Research
- Photonic and Optical Devices
- Radio Astronomy Observations and Technology
- Acoustic Wave Resonator Technologies
- Advanced Power Amplifier Design
- Precipitation Measurement and Analysis
- Soil Moisture and Remote Sensing
- Microwave and Dielectric Measurement Techniques
- Semiconductor Quantum Structures and Devices
- Particle accelerators and beam dynamics
- Icing and De-icing Technologies
- Terahertz technology and applications
- Antenna Design and Optimization
- Satellite Communication Systems
- Semiconductor Lasers and Optical Devices
- Advanced Thermodynamic Systems and Engines
- Astrophysics and Star Formation Studies
- Advanced NMR Techniques and Applications
- Physics of Superconductivity and Magnetism
- Astrophysics and Cosmic Phenomena
- Advanced MEMS and NEMS Technologies
- Full-Duplex Wireless Communications
Virginia Diodes (United States)
2014-2024
North Carolina State University
2022
National Radio Astronomy Observatory
2005-2017
Institute for Plasma Research
2016
The University of Texas at Austin
2016
Netherlands Institute for Radio Astronomy
2011
National Central University
2007
Jet Propulsion Laboratory
2005
University of Colorado Boulder
1996-2003
A design-oriented analysis of the microwave transmission-line class-E amplifier is presented. Experiments and harmonic-balance circuit simulations verify theoretical equations which predict class-E-amplifier output power, maximum frequency operation, dc-RF conversion efficiency. Experimental results at 0.5, 1,2, 5 GHz are At 0.5 GHz, 83% drain efficiency 80% power-added (PAE) measured, with an power 0.55 W, using Siemens CLY5 MESFET. These compared to a class-A class-F same device. 81% 72%...
Cryogenic cooling of receivers to reduce their noise temperature is especially important in radio astronomy, as the antenna determined by cosmic microwave background radiation (2.725 K) modified presence atmosphere. For frequencies up 120 GHz direct amplification at cryogenic temperatures typically employed using InP heterostructure field-effect transistors (HFETs) or, more recently, SiGe bipolar (HBTs). This article reviews developments this field and presents current state-of-the-art....
A W-band MMIC low-noise amplifier (LNA) was designed and fabricated using NGST's 35nm InP HEMT process. It packaged in a WR-12 module tested at 297K 17.5K ambient temperatures. At room temperature, the LNA has 26–30 dB gain from 70 to 92 GHz less than 300K noise temperature 65–86 GHz. minimum of 22K 85 40K 70–96 (below 30K 78–95 GHz). Gain is 27–31 94 Power dissipation cold 2.1 mW. Analysis also included investigate observed frequency shift with temperature. believed that these are lowest...
We describe the design, performance, and commissioning results for new ALMA Band 5 receiver channel, 163–211 GHz, which is in final stage of full deployment expected to be available observations 2018. This manuscript provides description cartridge serves as a reference observers using observations. At time writing this paper, Production Consortium consisting NOVA Instrumentation group, based Groningen, NL, GARD Sweden have produced delivered Observatory over 60 cartridges. All cartridges...
We recently used selective 2H labeling of BDPA to investigate the Overhauser Effect (OE) dynamic nuclear polarization (DNP) mechanism in insulating solids doped with 1,3-bis(diphenylene)-2-phenylallyl (BDPA), and established that α γ 1H spins on fluorene rings are responsible for generating a zero quantum (ZQ) mediated positive bulk polarization. Here, we establish phenyl relax via double-quantum (DQ) processes therefore contribute negative enhancements which attenuate OE-DNP. With...
Filters play an invaluable role in RF analysis and communications hardware, blocking unwanted signals, limiting bandwidth, attenuating harmonic components, etc. In waveguide construction for mm-wave frequencies, where the powers are generally low, iris-coupled-resonator bandpass filter has proven to be very practical amenable easy machining. At Virginia Diodes, much of our technology been constructed using standard "split-block" techniques, which high-precision computer numerical control...
Cloud ice play important roles in Earth's climate and weather systems through their interactions with atmospheric radiation, dynamics, energy precipitation processes. Submillimeter (submm) wave remote sensing at 200-1000 GHz is able to provide the sensitivity not covered by visible (VIS)/infrared (IR) low-frequency microwave (MW) sensors (10-183 GHz), measure cloud middle-to-upper troposphere. The IceCube 883-GHz radiometer latest of NASA's efforts advance technology readiness level (TRL)...
A 5-GHz high-efficiency feedback oscillator using a class-E amplifier is presented. The designed at 5.0 GHz for maximum conversion efficiency only quasilinear simulation techniques. of 59% measured with an output power 300 mW. can also be biased 600 mW 48%.
The development and measurements of solid-state active multiplier sources for DNP-NMR experiments is described in this paper. utilize power-combined Schottky diode frequency doublers as the final two stages. 250 mW output power was measured complete sources, one at GHz a second 262 GHz. Using 1.3 mm probe, DNP enhancements 115-120 were measured.
Solid-state sources and receivers are now available throughout the frequency range from 100 GHz to 3 THz. Although III-V MMIC amplifiers Si-Ge technology beginning extend this band, systems based on GaAs Schottky diodes still offer best performance for most applications. These include a variety of important applications in science, also test & measurement equipment laboratory use, such as VNA extenders. This paper will review progress with emphasis recent results its application.
In this paper, we compare two X-band high-efficiency switched-mode amplifiers designed around commercially available packaged MESFET's, one having a four times larger gate periphery than the other. The using and smaller devices are to operate in classes E F, respectively. device gives 685 mW output power with 7.4 dB gain 64% overall efficiency. 1.70 W 5.3 57% This an internal (or chip-level) power-combining efficiency for of 89% terms is compared combining circuit spatial amplifiers, goal...
A set of MMIC frequency multipliers and balanced mixers have been designed for the local oscillator system Atacama large millimeter array (ALMA). These millimeter-wave elements form a critical link in active multiplier chains between relatively low microwave oscillators very high submillimeter-wave, cooled LO subsystem. complete chipset four bands is described, along with preliminary results on prototypes two additional bands.
We report on the local oscillator (LO) development for ALMA 64-antenna sub-millimeter wave telescope array. Measurements of output power and AM noise are presented four wideband electronically-tuned MMIC-based LOs up to 710 GHz.
We present the design of several wideband, millimeter-wave, MMIC, medium power amplifiers using a newly developed high-power, high-yield, 70 nm gate-length GaAs MMIC pHEMT process. These cover range about 65-125 GHz, and were designed for purpose driving sub-millimeter wave multipliers in local oscillator subsystem Atacama Large Millimeter Array (ALMA) radio telescope. The highest-frequency this chipset have average output density over wide bandwidth 200 mW/mm, representing best performance...
Time-domain measurements of the output waveforms two 8-GHz high-efficiency power amplifiers, a 1-GHz frequency doubler, and 5-GHz doubler are presented in this paper. A new photoconductive probe has enabled nonintrusive time-domain voltage measurements, which confirm switched-mode class-E class-F amplifier operation. In order to analyze nonlinear amplifiers designed deliver sinusoidal wave load, voltages at characteristic points inside circuit need be known. multipliers, waveform track...
This paper describes a set of power amplifier (PA) modules containing InP high electron mobility transistor (HEMT) monolithic millimeter-wave integrated circuit (MMIC) chips. The chips were designed and optimized for local oscillator sources in the 90-130 GHz band Atacama large millimeter array telescope. feature 20-45 mW output power, to date highest from solid state HEMT MMIC above 110 GHz.
Presented here are the first measurements of a device under test from 1100-1500 GHz, in WM164 waveguide band. The instrument exhibits dynamic range ~80 dB and measured insertion loss some newly fabricated components agrees well with theoretical conductor waveguide.
The design of a single-sideband 675-693 GHz integrated polarimeter is presented here. compact module, measuring 1.5" x 0.75" includes the OMT, RF LNAs, image-reject filters, mixers, IF and LO active multiplier chain. Total power dissipation expected to be approximately 6W. Receiver noise temperature 6000K SSB. has been machined assembled with measurements at conference.
We present a 67--93.6 GHz spectral line survey of Orion-KL with the new 4 mm Receiver on Green Bank Telescope (GBT). The reaches unprecedented depths and covers low-frequency end 3 atmospheric window which has been relatively unexplored previously. entire spectral-line is published electronically for general use by astronomical community. calibration performance GBT also summarized.
A quasi-optical receiver front end consisting of a 10-GHz lens amplifier antenna array and three self-oscillating grid mixers is presented. The amplifies incoming plane waves incident from different directions focuses them to points where the are placed. Because angle-preserving nature amplifier, generate independent IF signals directions. resulting angle diversity useful for reducing multipath fading in communications.