About Commonwealth Fusion Systems:

Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.

Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future.

We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.

Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.

If that’s you and this role fits, we want to hear from you. Join the power movement as an RF Electronics Engineer

SPARC sustains fusion reactions by feeding >25MW of 120MHz RF power into the tokamak to heat the plasma to 100 million Kelvin. We need an RF Test Engineer to play a pivotal role in validating and testing the electronics and control systems that power the most ambitious RF plant in the world.

At this level, you are a hands-on executor and technical problem solver. You will be directly responsible for taking newly architected RF and power electronics from the benchtop to full-scale operation. Your day-to-day will span board-level bring-up, operating high-power RF transmitters, and integrating hardware with software controls to ensure SPARC achieves net energy.

For more information on the SPARC RF plant, see the SPARC journal papers here:

• Overview of the SPARC tokamak
• Physics basis for the ICRF system of the SPARC tokamak

What you'll do:

• Architect and design custom control boards, precision power supplies, and sensing circuits required to drive distributed, high-power solid-state RF amplifiers
• Partner closely with cross-functional teams, including software, RF, mechanical, and manufacturing engineers, to ensure your custom electronic designs integrate seamlessly into the broader system architecture
• Write comprehensive technical specifications for external vendors and internal matrix support teams to ensure manufactured components meet stringent requirements
• Perform advanced simulation and modeling of electronic circuits and power systems to validate performance
• Physically assemble and bring up initial prototypes on the bench, ensuring your designs transition flawlessly into the integrated RF system

What we’re looking for:

• Bachelor’s degree in Electrical Engineering or a related field
• 5+ years of hands-on experience designing power electronics, control boards, or RF support circuitry
• Hands-on experience using circuit simulation software (e.g., SPICE) to model and validate circuit designs
• Exceptional PCB design skills utilizing Altium or similar software, specifically geared toward instrumentation, sensing, power supplies, and control systems
• High proficiency in modeling tools to validate electronics architecture and mitigate EMI/EMC issues in high-power, high-noise environments

Bonus points for:

• Experience working with high voltage systems and in high voltage environments
• Background in requirements engineering, specifically decomposing high-level system requirements into actionable hardware specifications
• Direct experience working with RF systems, with a strong bonus for candidates who have worked on high-power RF heating systems
• Experience with thermal management techniques for densely packed, high-power printed circuit board assemblies
• Experience translating complex engineering needs into clear manufacturing specifications for contract manufacturers and cross-functional teams
• A strong systems-level understanding of modern high-performance embedded digital controllers and high-speed communications

Must-have Requirements:

• Ability to lift up to 50lbs
• Perform activities such as stooping, climbing, standing, typing 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

Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations.

Benefits include:

• Competitive compensation with equity
• 13 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities

LI-Onsite

At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.

We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.

This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.