Millimeter-wave system-on-chip advancement for fusion plasma diagnostics

Area of Science:

• Fusion plasma diagnostics
• Radio-frequency (RF) system-on-chip (SoC) technology
• Millimeter-wave (mmWave) technology

Background:

• Conventional discrete component assemblies for mmWave fusion plasma diagnostics face challenges like space inefficiency, installation inflexibility, low sensitivity, electromagnetic interference (EMI) susceptibility, and high costs.
• Advances in transistor fabrication enable hundreds of GHz operation, making mmWave diagnostics feasible for current and future tokamaks.
• Higher imaging resolution and data accuracy in plasma diagnostics are achieved by increasing the number of channels.

Purpose of the Study:

• To develop advanced mmWave fusion plasma diagnostic systems utilizing novel RF SoC technology.
• To overcome the limitations of conventional diagnostic methods, including cost, size, and sensitivity.
• To enable higher resolution and data accuracy in plasma measurements for fusion energy research.

Main Methods:

• Development of V-band (55-75 GHz) transmitter and receiver chips by the Davis Millimeter Wave Research Center (DMRC).
• Implementation of a Microwave Imaging Reflectometer (MIR) instrument utilizing these novel chips.
• Utilizing ultra-wideband operation (over 20 GHz) for plasma diagnostics, significantly exceeding bandwidths in commercial communication systems.
• Ongoing development of Gallium-Arsenide (GaAs) monolithic microwave integrated circuit (MMIC) receiver chips at W-band (75-110 GHz) and F-band (90-140 GHz).

Main Results:

• Successful development of V-band transmitter and receiver chips for MIR instruments.
• The transmitter can simultaneously illuminate 8 different frequencies within the 55-75 GHz range.
• The receiver offers signal amplification (>30 dB) and a 10-30x reduction in noise temperature compared to existing MIR instruments.
• Achieved higher imaging resolution and data accuracy through increased channel count enabled by SoC technology.

Conclusions:

• RF SoC technology provides a viable solution to overcome major challenges in mmWave fusion plasma diagnostics.
• The developed V-band chips significantly improve performance metrics like sensitivity and noise temperature.
• Future development towards W-band and F-band aims to enable measurements at higher toroidal magnetic fields, advancing fusion research capabilities.