Eric W. Bryerton

A W-band low-noise amplifier with 22K noise temperature

A W-band MMIC low-noise amplifier (LNA) was designed and fabricated using NGSTs 35nm InP HEMT process. It was packaged in a WR-12 module and tested at 297K and 17.5K ambient temperatures. At room temperature, the WR-12 LNA module has 26–30 dB gain from 70 to 92 GHz and less than 300K noise temperature from 65–86 GHz. At 17.5K ambient temperature, the WR-12 LNA module has a minimum noise temperature of 22K at 85 GHz and less than 40K noise temperature from 70–96 GHz (below 30K noise temperature from 78–95 GHz). Gain at 17.5K is 27–31 dB from 70 to 94 GHz. Power dissipation cold is 2.1 mW. Analysis is also included to investigate the observed frequency shift with ambient temperature. It is believed that these are the lowest noise temperature measured for a packaged W-band amplifier at both room and cryogenic temperatures.

A millimeter-wave diode-MMIC chipset for local oscillator generation in the ALMA telescope

A set of MMIC frequency multipliers and balanced mixers have been designed for the local oscillator system of the Atacama large millimeter array (ALMA). These millimeter-wave elements form a critical link in the active multiplier chains between the relatively low frequency microwave oscillators and the very high frequency submillimeter-wave, cooled multipliers of the LO subsystem. A complete chipset for four frequency bands is described, along with preliminary results on prototypes for two additional bands.

Development of electronically tuned local oscillators for ALMA

We report on the local oscillator (LO) development for the ALMA 64-antenna sub-millimeter wave telescope array. Measurements of output power and AM noise are presented for four wideband electronically-tuned MMIC-based LOs up to 710 GHz.

Medium power amplifiers covering 90-130 GHz for the ALMA telescope local oscillators

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 for the Atacama large millimeter array telescope. The modules feature 20-45 mW of output power, to date the highest power from solid state HEMT MMIC modules above 110 GHz.

Ultra low noise cryogenic amplifiers for radio astronomy

Cryogenic cooling of receivers to reduce their noise temperature is especially important in radio astronomy, as the antenna noise temperature is determined by the cosmic microwave background radiation (2.725 K) modified by the presence of atmosphere. For frequencies up to 120 GHz direct amplification at cryogenic temperatures is typically employed using InP heterostructure field-effect transistors (HFETs) or, more recently, SiGe heterostructure bipolar transistors (HBTs). This article reviews developments in this field and presents the current state-of-the-art. Examples of noise performance of amplifiers using InP HFETs and SiGe HBTs are compared with the model predications. Some gaps in our current understanding of experimental results are emphasized, and some comments on possible future developments are offered.

Wideband medium power amplifiers using a short gate-length GaAs MMIC process

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 amplifiers cover a range of about 65–125 GHz, and were designed for the purpose of driving sub-millimeter wave multipliers in the local oscillator subsystem of the Atacama Large Millimeter Array (ALMA) radio telescope. The highest-frequency amplifiers in this chipset have average output power density over wide bandwidth of 200 mW/mm, representing the best performance to date for GaAs pHEMTs above W-Band.

Wideband low-phase-noise high-power W-band signal sources

This paper describes the development of electronically-tunable wideband low-phase-noise millimeter-wave signal sources. These sources are designed to drive cooled Schottky multipliers to supply the LO for the ALMA telescope array. Each phase-locked driver consists of a YTO, active multiplier chain (AMC), and a power amplifier. Measurements of a prototype driver electronically tunable from 72-85 GHz with greater than 50 mW output power are presented. Additive phase noise of individual amplifiers and multipliers is described. Long-term phase drift measurements are reported. Preliminary W-band amplitude noise measurements using a SIS mixer with a YTO-based driver chain and Gunn oscillator LO are also presented. All measurements indicate that the stringent ALMA LO specifications can be met with this architecture.

A Cryogenic Integrated Noise Calibration and Coupler Module Using a MMIC LNA

A new cryogenic noise calibration source for radio astronomy receivers is presented. Dissipated power is only 4.2 mW, allowing it to be integrated with the cold part of the receiver. Measured long-term stability, sensitivity to bias voltages, and noise power output versus frequency are presented. The measured noise output versus frequency is compared to a warm noise diode injected into a cryogenic K-band receiver and shows the integrated noise module to have less frequency structure, which will result in more accurate astronomical flux calibrations. It is currently in operation on the new seven-element K-band focal plane array receiver on the National Radio Astronomy Observatory Robert C. Byrd Green Bank Telescope.

A 660-GHz electronically tunable local oscillator

We present an electronically tunable local oscillator from 630-675 GHz with upcoming extension to 600-720 GHz using a 13.33-16.00 GHz source followed by a x45 multiplier chain. Output power measurements show >30 ¿W from 630-675 GHz. FTS and receiver noise measurements using this LO are also presented.

Low-noise sub-millimeter wave local oscillators for ALMA

High signal-to-noise ratio sub-millimeter wave local oscillators (LOs) were developed and produced for the Atacama Large Millimeter Array (ALMA). They cover fractional bandwidths of 15-25% from 92 to 942 GHz. The LOs were designed and tested for high signal-to-noise ratio since they are used to drive single-ended mixers. Integrated millimeter-wave multi-chip MMIC modules, employing custom and commercial MMICs, were designed to yield the required power and SNR performance. 73 modules of the LO have been produced for each of the six bands to date, with two more bands currently under construction.