RF / Electromagnetics Engineer

Infleqtion is a global quantum technology company solving the world’s most challenging problems. The company harnesses quantum mechanics to build and integrate quantum computers, sensors, and networks. From fundamental physics to leading edge commercial products, Infleqtion enables “quantum everywhere” through our ecosystem of devices and platforms.

POSITION SUMMARY

This role focuses on RF architecture design, electromagnetic structures, and EM measurement/calibration in support of advanced quantum and atomic sensor systems. The engineer will serve as a senior technical contributor responsible for developing RF test environments, designing and characterizing EM structures, contributing to LO and signal-chain architecture, and translating experimental results into clear technical direction and measurable system performance. Much of the test and characterization work is in the RF and microwave regime, while familiarity with lower-frequency design and components is also valuable.

This is a fully onsite role based in Boulder or Louisville, Colorado. The position emphasizes technical ownership, cross-functional coordination, and clear communication of progress and risk to leadership. Prior experience with atomic or quantum sensors is helpful but not required.

JOB RESPONSIBILITIES

The duties and responsibilities outlined below include essential functions of the role. Depending on business needs, this role may perform a combination of some or all of the following duties. Duties, responsibilities, and activities may change, or new ones may be assigned at any time with or without notice.

• Own simulation, design, build, and characterization of electrodes and other RF/EM structures supporting sensor and test system development

• Develop free-space RF testbeds and controlled RF environments, including requirements definition, design support, build-out, validation, and continuous improvement

• Define and execute EM measurement and calibration methods for radiated field strength, coupling, shielding, and measurement uncertainty

• Develop calibration and measurement approaches for controlled-source and signal-of-opportunity field characterization

• Contribute to RF architecture development across low-frequency through microwave operation, including signal-chain partitioning and interface definition

• Contribute to local oscillator architecture, generation, and distribution approaches for lower- and higher-frequency operation

• Evaluate LO leakage, spurious responses, phase noise, and coupling paths, and recommend mitigations

• Build and maintain LO noise, signal-chain, and system-level link budgets to support design trades and performance analysis

• Support development of frequency conversion and analog interface approaches, including baseband-to-IF concepts as needed

• Lead EM simulations to guide hardware design, measurement setup design, and interpretation of test results

• Define RF performance metrics and comparison frameworks that support clear datasheet-style communication for novel sensing capabilities

• Assist in the design and execution of directionality characterization experiments and related validation plans

• Specify requirements for internal or external RF test environments and coordinate with vendors or subcontractors as needed

• Collaborate with physicists, electrical engineers, mechanical engineers, software engineers, and external partners to integrate technical contributions

• Develop automation, instrument control, data processing, and reporting workflows for RF/EM test activities

• Execute hardware bring-up, calibration, troubleshooting, and root-cause analysis across prototype and integrated systems

• Document designs, test methods, calibration procedures, and results to support technical reviews and future development

• Communicate technical progress, trade studies, risks, and recommendations clearly to leadership and cross-functional teams

• Support lab and field testing, proposal activities, customer demonstrations, and other program needs as required

Requirements:
QUALIFICATIONS: EDUCATION AND EXPERIENCE

• BS or MS in Electrical Engineering, Physics, Applied Physics, Electromagnetics, or a related field

• 5-10+ years of experience in RF, microwave, electromagnetics, antenna, or advanced sensor hardware/system development

• Demonstrated experience designing and characterizing electrodes, RF/EM structures, test hardware, or related components

• Experience with free-space or radiated RF measurements, calibration methods, and controlled test environment development

• Experience contributing to RF architecture or signal-chain design across low-frequency through microwave operation

• Strong hands-on RF lab skills with instrumentation such as vector network analyzers, spectrum analyzers, signal generators, oscilloscopes, and power meters

• Ability to take ownership of technical tasks, coordinate with internal teams and subcontractors, and communicate progress and risks effectively

• Experience using EM simulation and scripting tools to support design, test, automation, and troubleshooting

• U.S. citizenship preferred due to the nature of customers, programs, and potential export-controlled work

• This position may require access to information protected under U.S. export control laws and regulations, including the Export Administration Regulations (EAR) and the International Traffic in Arms Regulations (ITAR). Please note that any offer for employment may be conditioned on authorization to receive software or technology controlled under these U.S. export control laws and regulations without sponsorship for an export license

PREFERRED / NICE-TO-HAVE SKILLS

• Strong Python skills for lab automation, data processing, and technical reporting

• Experience with HFSS and/or other EM simulation tools for RF and electromagnetic design

• Experience specifying, designing, or building anechoic chambers, radiated test setups, or other controlled RF test environments

• Experience with directionality characterization, field mapping, or free-space calibration techniques

• Experience with low-phase-noise LO chains, synthesizers, mixers, or frequency-conversion architectures

• Experience with atomic or quantum sensors, government-funded R&D programs, or other advanced sensing applications

TRAVEL

Up to 10% travel may be required.

WORKING CONDITIONS and PHYSICAL REQUIREMENTS

Work will normally be performed in an office and laboratory environment and around technical equipment including computers, RF test equipment, and laboratory instrumentation. Able to sit, stand, bend, lift and carry up to 40 pounds without assistance. Able to efficiently use automated office equipment such as laptops, copiers, and printers; able to effectively engage in communications (via phone, computer, or in-person). Any required Personal Protective Equipment will be provided and must be properly used in accordance with company requirements.

Benefits:
• Salary range: $140,000 to $170,000

• 100% company-paid medical, dental, vision, short/long-term disability
• Employer-funded Health Savings Account
• Unlimited PTO
• 401(k) match
• Company-paid Life and AD&D Insurance
• Flexible Savings Account
• Paid FMLA, Maternity/Paternity Leave
• Employee Assistance Program
• Student Loan Repayment
• Equity Program