Solid-state frequency multipliers are used to produce tunable broadband sources at millimeter and submillimeter wavelengths. The maximum power produced by a single chip is limited by the electrical breakdown of the semiconductor and by the thermal management properties of the chip. The solution is to split the drive power to a frequency tripler using waveguides to divide the power among four chips, then recombine the output power from the four chips back into a single waveguide.
To achieve this, a waveguide branch-line quadrature hybrid coupler splits a 100- GHz input signal into two paths with a 90° relative phase shift. These two paths are split again by a pair of waveguide Y-junctions. The signals from the four outputs of the Y-junctions are tripled in frequency using balanced Schottky diode frequency triplers before being recombined with another pair of Y-junctions. A final waveguide branch-line quadrature hybrid coupler completes the combination.
Using four chips instead of one enables using four-times higher power input, and produces a nearly four-fold power output as compared to using a single chip. The phase shifts introduced by the quadrature hybrid couplers provide isolation for the input and output waveguides, effectively eliminating standing waves between it and surrounding components. This is accomplished without introducing the high losses and expense of ferrite isolators.
A practical use of this technology is to drive local oscillators as was demonstrated around 300 GHz for a heterodyne spectrometer operating in the 2–3-THz band. Heterodyne spectroscopy in this frequency band is especially valuable for astrophysics due to the presence of a very large number of molecular spectral lines. Besides high-resolution radar and spectrographic screening applications, this technology could also be useful for laboratory spectroscopy.
This work was done by Robert H. Lin, John S. Ward, Peter J. Bruneau, and Imran Mehdi of Caltech; Bertrand C. Thomas of Oak Ridge Associated Universities; and Alain Maestrini of the Observatoire de Paris for NASA’s Jet Propulsion Laboratory. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Semiconductors & ICs category. NPO-46567
This Brief includes a Technical Support Package (TSP).
Quad-Chip Double-Balanced Frequency Tripler
(reference NPO-46567) is currently available for download from the TSP library.
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Overview
The document outlines the development and performance of NASA's Quad-Chip Double-Balanced Frequency Tripler, specifically designed for operation in the 260-340 GHz frequency range. This innovative device is a significant advancement in high-frequency electronics, utilizing a quad-chip configuration that incorporates a total of 24 anodes. The large number of anodes is essential for enhancing power handling capabilities, which is crucial for applications in aerospace and other high-tech fields.
The performance data presented in the document includes output power and efficiency metrics at various input power levels. For instance, the tripler demonstrates varying output power and efficiency when tested at an input power of 200 mW and 400 mW, with specific performance characteristics noted at an output frequency of 285.5 GHz. The efficiency and output power are graphically represented, illustrating the relationship between input power and the resulting output performance.
Additionally, the document discusses the integration of a Four-Way Power Combiner, which operates within the 87-113 GHz range and is designed to work in conjunction with the tripler. This combiner is capable of handling input power levels between 300-400 mW and produces an output power of 35-40 mW, further enhancing the overall system's performance.
The Quad-Chip Double-Balanced Frequency Tripler is part of NASA's broader efforts to advance aerospace-related technologies with potential applications beyond space exploration. The document emphasizes the importance of these developments in contributing to scientific and commercial advancements, highlighting the role of the National Aeronautics and Space Administration in fostering innovative technologies.
The Technical Support Package serves as a comprehensive resource for understanding the tripler's design, fabrication, and testing processes. It is intended for stakeholders interested in the technological implications of this research, including potential commercial applications. The document also includes contact information for further inquiries, emphasizing NASA's commitment to sharing knowledge and fostering partnerships in innovative technology development.
In summary, this document provides a detailed overview of the Quad-Chip Double-Balanced Frequency Tripler, showcasing its design, performance metrics, and potential applications, while also highlighting NASA's role in advancing high-frequency technology for various uses.
