RF Engineer (QRF)

Infleqtion is a global quantum technology company solving some of the worlds most challenging problems. We build and integrate quantum computers sensors and networks. From fundamental physics to leading-edge commercial products Infleqtion enables quantum everywhere through an ecosystem of devices and platforms.

Quantum Spectrum also known as QRF develops fieldable radio-frequency sensing systems based on Rydberg atoms. The team combines atomic physics lasers and photonics RF electronics embedded controls software and precision hardware to turn laboratory prototypes into repeatable integrated sensing systems.

Position Summary

Infleqtion is seeking a hands-on RF Engineer to establish and own the RF and electromagnetics discipline within the QRF team. Reporting to the QRF Product Engineer this engineer will lead the design modeling integration calibration and verification of broadband RF hardware and test environments. The work centers on calibrated electromagnetic field generation and delivery sensor interfaces low-noise signal chains RF structures and traceable measurementnot the modem protocol or network design typical of a conventional communications role. Prior quantum experience is not required but the successful candidate must be able and motivated to learn the atomic physics and Rydberg sensing principles needed to make sound RF design decisions.

Job Responsibilities

The duties and responsibilities below describe the essential functions of the role. Depending on business needs the position may perform some or all these duties. Duties responsibilities and activities may change or new ones may be assigned at any time with or without notice.

• Own RF and electromagnetic requirements architectures interfaces performance budgets and verification methods for QRF sensor heads test systems and integrated hardware.
• Design simulate build and characterize RF structures such as electrodes resonators antennas fixtures interconnects shielding and field delivery hardware.
• Develop RF signal generation amplification filtering frequency conversion local oscillator distribution and analog interface approaches that support broadband sensor operations
• Build and improve controlled conducted and radiated RF test environments including field generation field mapping and calibration configurations.
• Define and execute measurements for field strength frequency response impedance insertion and return loss phase coupling shielding noise linearity dynamic range spurious response and uncertainty.
• Build and maintain RF performance budgets for gain loss noise phase noise leakage coupling compression harmonics spurious signals and other limits that affect sensor performance.
• Lead RF hardware bring-up characterization troubleshooting and root-cause analysis across benchtop subsystem sensor head and integrated system configurations.
• Use electromagnetic and circuit simulation to guide hardware and test fixture design component selection design trades and interpretation of measured results; reconcile models with laboratory data.
• Develop Python or comparable automation for instrument control parameter sweeps calibration regression testing data analysis and technical reporting.
• Work with applied physicists to relate RF field delivery and signal-chain behavior to atomic response sensitivity bandwidth stability dynamic range and repeatability.
• Collaborate with optical-mechanical electrical embedded-systems software manufacturing and technician personnel to define interfaces resolve cross-domain problems and transfer RF designs into repeatable builds and acceptance tests.
• Document designs models interfaces calibration methods test procedures configurations results trade studies risks and recommendations for technical reviews verification and future production.

• Bachelors degree in electrical engineering applied physics electromagnetics or a closely related technical field or equivalent practical experience.
• At least five years of relevant professional experience in RF microwave electromagnetics antenna advanced sensor or related hardware development.
• Demonstrated experience independently designing building integrating characterizing and troubleshooting RF or microwave hardware and test systems.
• Hands-on laboratory experience with equipment such as vector network analyzers spectrum or vector-signal analyzers signal generators oscilloscopes power meters and RF probes or sensors.
• Practical knowledge of impedance matching gain and loss noise dynamic range linearity phase noise spurious response leakage coupling shielding grounding and measurement uncertainty.
• Experience developing RF requirements signal-chain budgets test methods calibration approaches and quantitative acceptance criteria.
• Experience with at least one RF circuit or electromagnetic simulation environment such as Ansys HFSS CST Studio Suite Keysight ADS Cadence AWR COMSOL FEKO or an equivalent tool.
• Experience using Python MATLAB LabVIEW or a comparable environment for instrument control test automation modeling or data analysis.
• Ability to own the RF domain document technical work clearly collaborate across disciplines and learn the atomic physics spectroscopy and Rydberg sensing concepts needed to connect RF design choices with quantum sensor performance.
• Preferred Qualifications
• Experience with Rydberg atoms electromagnetically induced transparency atomic RF electrometry quantum sensing atomic clocks or related atomic physics instrumentation.
• Experience with calibrated free-space or radiated RF measurement field mapping anechoic or controlled RF environments TEM or GTEM cells or measurement-uncertainty analysis.
• Experience designing or characterizing electrodes RF resonators antennas couplers fixtures shielding enclosures or other application-specific electromagnetic structures.
• Experience with low-phase-noise oscillators synthesizers mixers frequency-conversion architectures distribution networks or low-noise analog signal chains.
• Experience with RF PCB design controlled-impedance routing grounding shielding signal integrity or electromagnetic-interference and compatibility mitigation.
• Experience with software-defined radio RFSoC platforms digital signal processing RF data acquisition or mixed hardware-software receiver systems.
• Experience transferring complex RF hardware from prototype development into repeatable manufacturing calibration and acceptance testing.
• Experience with configuration-controlled hardware and verification evidence for aerospace defense scientific instrumentation or U.S. government programs; a current or previously held U.S. government security clearance is preferred but not required.

Work is performed primarily on site in laboratory office production and integration/test environments and involves work around RF and microwave equipment laser systems electronic test equipment optical tables tools and precision instrumentation. Required personal protective equipment will be provided and must be used in accordance with company requirements. With or without reasonable accommodation the role requires the ability to work at laboratory benches for extended periods perform fine electronic and mechanical adjustment tasks and occasionally lift and carry equipment or components weighing up to forty pounds. Up to 10% travel may be required.

• Salary Range: per year $145000 $170000
• 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

Notice to Recruitment Agencies:

Infleqtion does not accept unsolicited resumes from agencies. Infleqtion is not responsible for any fees related to unsolicited resumes.

Required Experience:

IC