Emi Engineer Jobs in California (NOW HIRING)

Castelion is redefining defense development through rapid iteration, aggressive testing, and modern commercial manufacturing at scale. We design, build, and test next-generation long-range strike weapon systems to give the United States and its Allies a decisive advantage and deter future conflicts.

We are hiring an EMI/EMC Engineer to own electromagnetic compatibility across our avionics hardware stack. This role is responsible for ensuring that avionics electronics, including flight computers, sensors, communications systems, and power electronics, operate reliably without causing or suffering from electromagnetic interference.

• Integrate EMI/EMC considerations early into avionics hardware design, working closely with PCB designers and hardware engineers
• Review schematics and PCB layouts to ensure proper grounding, filtering, shielding, and return path integrity
• Develop mitigation strategies including filtering, cable shielding, bonding, and enclosure design
• Support system-level EMI risk analysis and identify potential interference sources across avionics subsystems
• Plan and execute EMI/EMC validation testing including radiated and conducted emissions and susceptibility testing
• Troubleshoot electromagnetic interference issues at the board, cable harness, and system levels
• Analyze test data to identify root causes of EMI issues and drive corrective design actions
• Collaborate with avionics test engineers to build and refine test setups for EMI validation
• Develop internal design guidelines and best practices to reduce EMI risk in future hardware iterations
• Document test results, mitigation strategies, and engineering recommendations

• Bachelor's degree in Electrical Engineering or related field
• Hands‑on experience with EMI/EMC testing, troubleshooting, or mitigation in electronic hardware systems
• Strong understanding of grounding, shielding, filtering, and electromagnetic coupling mechanisms
• Experience using lab instrumentation such as spectrum analyzers, oscilloscopes, signal generators, and current probes
• Ability to diagnose hardware interference issues and translate findings into practical design improvements
• Experience working closely with electrical hardware or PCB design teams
• Strong troubleshooting and problem‑solving skills in lab environments
• Ability to work cross‑functionally with hardware, test, and manufacturing teams

• Experience supporting EMI/EMC compliance testing such as MIL‑STD‑461 or DO‑160
• Familiarity with avionics, RF systems, or high‑speed digital electronics
• Experience working with cable harnessing, connectors, and shielding strategies in aerospace systems
• Experience debugging EMI issues at board, subsystem, or platform level
• Experience collaborating with external EMI compliance laboratories
• Familiarity with PCB design tools such as Altium or similar ECAD tools
• Experience with electromagnetic modeling or simulation tools

• Avionics systems pass EMI/EMC validation and qualification. Own the electromagnetic compatibility performance of avionics hardware and ensure systems meet internal requirements and external standards prior to flight and production.
• EMI risks are identified and mitigated early in hardware design. Partner with PCB, harness, and mechanical engineers to prevent interference issues before hardware reaches late‑stage testing, reducing redesign cycles and accelerating hardware maturation.
• Rapid diagnosis and resolution of electromagnetic interference issues. Lead root‑cause analysis of EMI failures during integration and testing, implement mitigation strategies, and establish internal design guidelines to improve electromagnetic robustness across future avionics builds

• Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break‑through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.
• High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.
• Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company‑desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

• To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.

All employees are granted long‑term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.