A monolithic microwave integrated circuit (MMIC) has been designed to function as a low-power-consumption, low-noise amplifier (LNA) at frequencies from about 65 to about 110 GHz. This MMIC incorporates TRW's state-of-the-art, InP-based, high-electron-mobility transistors (HEMTs) coupled with coplanar- waveguide (CPW) transmission lines, thin-film resistors, and thin-film capacitors. The MMIC is mounted in a waveguide module with CPW-to-waveguide transitions of the probe type (see figure).

A Four-Stage MMIC LNA is mounted in a split-block waveguide module. The dimensions of the MMIC chip are 2 by 0.73 by 0.075 mm.
An unusual feature of the circuit is a path for a pilot signal with a typical frequency of 500 MHz. This path is through the same transistors used to amplify the millimeter-wave signal. The pilot signal is applied through a pilot input terminal (the upper left pad in the figure) and appears at a pilot output terminal (the upper right pad in the figure). The low-level pilot signal is coupled from one bias circuit to the next and does not interact appreciably with the millimeter-wave signal. The pilot signal is meant to be used to measure fluctuations in the gain of the transistors; such measurements are useful in applications (e.g., radiometry) in which fluctuations in gain can affect measurements.

The MMIC is designed to operate in the presence of cooling by a suitable cryogenic apparatus. Seventeen waveguide modules containing copies of the MMIC were tested for noise temperature by use of a variable-temperature waveguide with a 20-dB attenuator and a precise diode temperature sensor. The range of noise temperatures over the 85-to-115-GHz frequency range was found to be 30 to 107 K at an operating temperature of 24 K. The noise at room operating temperature was found to range from 250 to 470 K. In other tests, the MMICs were found to be capable of producing 20 dB of gain while consuming as little as 1.4 mW of dc power.

This work was done by Todd Gaier and Sander Weinreb of Caltech, Neal Erickson of the University of Massachusetts, and Richard Lai of TRW for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp  under the Electronic Components and Systems category.

NPO-20752

Topics:
Amplifiers Capacitors Connectors and terminals Electric power grid Electrical systems Electronic equipment Electronics & Computers Energy storage systems Noise Sensors and actuators Transistors
This Brief includes a Technical Support Package (TSP).
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InP HEMT MMIC Low-Noise Amplifier for 65 to 110 GHz

(reference NPO-20752) is currently available for download from the TSP library.

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NASA Tech Briefs Magazine

This article first appeared in the February, 2002 issue of NASA Tech Briefs Magazine (Vol. 26 No. 2).

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Overview

The document presents a technical overview of a monolithic microwave integrated circuit (MMIC) designed as a low-noise amplifier (LNA) for frequencies ranging from 65 to 110 GHz. Developed by a team from NASA's Jet Propulsion Laboratory, including Neal Erickson, Richard Lai, Sander Weinreb, and Todd Gaier, this MMIC utilizes state-of-the-art InP-based high-electron-mobility transistors (HEMTs) and incorporates coplanar-waveguide (CPW) transmission lines, thin-film resistors, and capacitors.

Key features of the MMIC include its low power consumption and low noise characteristics, making it suitable for various applications, particularly in radiometry where precise measurements are critical. The MMIC operates effectively in both cryogenic (24 K) and room temperature (300 K) environments, with noise temperatures measured between 30 to 107 K at cryogenic temperatures and 250 to 470 K at room temperature. The device is capable of delivering a gain of 20 dB while consuming as little as 1.4 mW of DC power.

An innovative aspect of the design is the inclusion of a pilot signal path, which operates at a typical frequency of 500 MHz. This pilot signal is routed through the same transistors used for amplifying the millimeter-wave signal, allowing for real-time monitoring of gain fluctuations without significant interaction with the primary signal. This feature is particularly beneficial in applications where maintaining consistent gain is essential.

The MMIC is housed in a waveguide module that facilitates CPW-to-waveguide transitions, ensuring efficient signal transmission. The document also references a publication accepted for the IEEE MTT Symposium, which details the performance metrics and modeling of the device.

Overall, this MMIC represents a significant advancement in low-noise amplification technology, combining high performance with low power requirements, making it a valuable tool for scientific and engineering applications in the millimeter-wave frequency range. The work is part of ongoing research and development efforts at NASA, aimed at enhancing the capabilities of space and terrestrial communication systems.