Packaging of MMIC LNA (monolithic microwave integrated circuit low-noise amplifier) chips at frequencies over 200 GHz has always been problematic due to the high loss in the transition between the MMIC chip and the waveguide medium in which the chip will typically be used. In addition, above 200 GHz, wirebond inductance between the LNA and the waveguide can severely limit the RF matching and bandwidth of the final waveguide amplifier module.
This work resulted in the development of a low-loss quartz waveguide transition that includes a capacitive transmission line between the MMIC and the waveguide probe element. This capacitive transmission line tunes out the wirebond inductance (where the wire-bond is required to bond between the MMIC and the probe element). This inductance can severely limit the RF matching and bandwidth of the final waveguide amplifier module.
The amplifier module consists of a quartz E-plane waveguide probe transition, a short capacitive tuning element, a short wire-bond to the MMIC, and the MMIC LNA. The output structure is similar, with a short wire-bond at the output of the MMIC, a quartz E-plane waveguide probe transition, and the output waveguide. The quartz probe element is made of 3-mil quartz, which is the thinnest commercially available material. The waveguide band used is WR4, from 170 to 260 GHz. This new transition and block design is an improvement over prior art because it provides for better RF matching, and will likely yield lower loss and better noise figure.
The development of high-performance, low-noise amplifiers in the 180-to- 700-GHz range has applications for future earth science and planetary instruments with low power and volume, and astrophysics array instruments for molecular spectroscopy.
This frequency band, while suitable for homeland security and commercial applications (such as millimeter-wave imaging, hidden weapons detection, crowd scanning, airport security, and communications), also has applications to future NASA missions. The Global Atmospheric Composition Mission (GACM) in the NRC Decadel Survey will need low-noise amplifiers with extremely low noise temperatures, either at room temperature or for cryogenic applications, for atmospheric remote sensing.
This work was done by Sharmila Padmanabhan, King Man Fung, Pekka P. Kangaslahti, Alejandro Peralta, Mary M. Soria, David M. Pukala, Seth Sin, and Lorene A. Samoska of Caltech; and Stephen Sarkozy and Richard Lai of Northrop Grumman Corporation for NASA’s Jet Propulsion Laboratory. NPO-48436
This Brief includes a Technical Support Package (TSP).
Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions
(reference NPO-48436) is currently available for download from the TSP library.
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Overview
The document titled "Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions" (NPO-48436) is a technical support package from NASA's Jet Propulsion Laboratory (JPL), detailing advancements in high-frequency amplifier technology. The focus is on a new amplifier module designed to operate within the 260 GHz frequency band, utilizing quartz waveguide transitions for enhanced performance.
Key components of the project include a waveguide block specifically designed for an amplifier chip that operates across a frequency range of 170-260 GHz. The design incorporates a WR4 waveguide, which is crucial for efficient signal transmission at these high frequencies. The document features Solidworks drawings and HFSS models that illustrate the interior of the WR4 block and the E-plane probe, which is made from 3 mil quartz substrate material. This choice of material is significant as it is readily available from commercial vendors, facilitating broader application and manufacturing.
The E-plane probe, developed by Sharmila Padmanaban, was tested using a microstrip thru-line to evaluate its design and the overall waveguide package. The results indicate a usable bandwidth of 220-265 GHz for the WR4 version, demonstrating its capability to handle a wide range of frequencies effectively. Notably, the back-to-back probe and waveguide loss measured only 2 dB at 246 GHz, indicating high efficiency and low signal loss, which are critical factors in high-frequency applications.
The document emphasizes the collaborative efforts of a team of researchers, including A. Fung, P. Kangaslahti, S. Padmanaban, A. Peralta, D. Pukala, L. Samoska, S. Sin, and M. Soria, all affiliated with JPL and the California Institute of Technology. Their work is part of NASA's Commercial Technology Program, aimed at disseminating aerospace-related developments with potential technological, scientific, or commercial applications.
Overall, this technical support package serves as a comprehensive resource for understanding the design, testing, and implications of the new amplifier module, highlighting its significance in advancing high-frequency communication technologies. The findings and innovations presented in this document are expected to contribute to various applications in aerospace and beyond, showcasing the ongoing efforts to push the boundaries of technology in high-frequency domains.
