Principal RF Systems Engineer

Commonwealth Fusion Systems•Devens, MA

3d•Onsite

About The Position

Commonwealth Fusion Systems (CFS) is seeking a Principal RF Systems Engineer to play a pivotal role in building the most powerful RF plant in the world for the SPARC tokamak. This role involves shaping the high-level technical direction and being deeply hands-on in the integration of high-power electronics, solid-state amplification, and complex transmission networks to ensure SPARC achieves net energy. The SPARC RF plant will sustain fusion reactions by feeding over 25MW of 120MHz RF power into the tokamak to heat the plasma to 100 million Kelvin. At this level, you will be a highly influential architect of the system.

Requirements

Bachelor’s degree in Electrical Engineering, Physics, or a related field (Master’s or Ph.D. strongly preferred for this level)
15+ years of hands-on experience in high-power RF systems, radar, particle accelerators, or heavy industrial power electronics
Proven intuition for high-power RF environments, specifically hands-on experience measuring forward and reflected RF power, diagnosing RF arcs, and designing the timing and electronics to mitigate them.
Exceptional skills in RF circuit and electronics design (Altium or similar) specifically geared toward instrumentation, sensing, control, and system integration.
Experience in EMI/EMC mitigation to ensure sensitive timing and RF detection circuits operate reliably within extreme high-power, high-noise environments.
High proficiency in RF/Microwave simulation software (CST, HFSS, etc.) to validate architectural decisions before physical integration.
A strong systems-level understanding of modern high-performance embedded digital controllers, high speed communications, and fundamentals of mechanical/thermal design to interface effectively with cross-functional teams.
Perform activities such as stooping, climbing, typing, standing, or sitting for extended periods of time.
Willingness to travel or work required nights/weekends/on-call occasionally.
Work in a facility that contains industrial hazards including heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics.
Compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws”).

Responsibilities

Shape System Architecture: Play a critical role in the end-to-end design and integration strategy for RF plants for tokamaks, collaborating with other senior engineers to ensure seamless interaction between RF sources, matching networks, and the dynamic plasma load.
Guide Solid-State & Electronics Integration: Act as a key driver in the architecture and design of the electronics ecosystems required to integrate massive, distributed RF systems, with a heavy emphasis on solid-state amplifier technology and associated power supplies.
Spearhead Instrumentation & Control (I&C): Take the initiative in designing and integrating advanced RF signal detection, measurement circuits, and embedded digital controllers that interface seamlessly with SPARC’s central data collection systems.
Tame High-Power Delivery: Serve as a central figure in the hands-on design, integration, and optimization of critical high-power transmission components, specifically large-diameter coax lines and dynamic impedance matching networks.
Hands-on Technical Mentorship: Act as a senior technical authority on the floor. You will be actively involved in commissioning equipment, troubleshooting the most complex system-level hardware discrepancies, and organically mentoring junior engineers to elevate the entire RF team's capabilities.