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,designingand 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 Own simulation, design, build, and characterization of electrodes and other RF/EM structures supporting sensor and test system developmentDevelop free-space RF testbeds and controlled RF environments, including requirements definition, design support, build-out, validation, and continuous improvementDefine and execute EM measurement and calibration methods for radiated field strength, coupling, shielding, and measurement uncertaintyDevelop calibration and measurement approaches for controlled-source and signal-of-opportunity field characterizationContribute to RF architecture development across low-frequency through microwave operation, including signal-chain partitioning and interface definitionContribute to local oscillator architecture, generation, and distribution approaches for lower- and higher-frequency operationEvaluate LO leakage, spurious responses, phase noise, and coupling paths, and recommend mitigationsBuild andmaintainLO noise, signal-chain, and system-level link budgets to support design trades and performance analysisSupport development of frequency conversion and analog interface approaches, including baseband-to-IF concepts as neededLead EM simulations to guide hardware design, measurement setup design, and interpretation of test resultsDefine RF performance metrics and comparison frameworks that support clear datasheet-style communication for novel sensing capabilitiesAssistin the design and execution of directionality characterization experiments and related validation plansSpecify requirements for internal or external RF test environments and coordinate with vendors or subcontractors as neededCollaborate with physicists, electrical engineers, mechanical engineers, software engineers, and external partners to integrate technical contributionsDevelop automation, instrument control, data processing, and reporting workflows for RF/EM test activitiesExecute hardware bring-up, calibration, troubleshooting, and root-cause analysis across prototype and integrated systemsDocument designs, test methods, calibration procedures, and results to support technical reviews and future developmentCommunicate technical progress, trade studies, risks, and recommendations clearly to leadership and cross-functional teamsSupport lab and field testing, proposal activities, customer demonstrations, and otherprogram needs asrequiredQUALIFICATIONS: EDUCATION AND EXPERIENCE BS or MS in Electrical Engineering, Physics, Applied Physics, Electromagnetics, or a related field5-10+ years of experience in RF, microwave, electromagnetics, antenna, or advanced sensor hardware/system developmentDemonstrated experience designing and characterizing electrodes, RF/EM structures, test hardware, or related componentsExperience with free-space or radiated RF measurements, calibration methods, and controlled test environment developmentExperience contributing to RF architecture or signal-chain design across low-frequency through microwave operationStrong hands-on RF lab skills with instrumentation such as vector network analyzers, spectrum analyzers, signal generators, oscilloscopes, and power metersAbility to take ownership of technical tasks, coordinate with internal teams and subcontractors, and communicate progress and risks effectivelyExperience using EM simulation and scripting tools to support design, test, automation, and troubleshootingU.S. citizenship preferred due to the nature of customers, programs, and potential export-controlled workThis 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 licensePREFERRED / NICE-TO-HAVE SKILLS Strong Python skills for lab automation, data processing, and technical reportingExperience with HFSS and/or other EM simulation tools for RF and electromagnetic designExperience specifying, designing, or building anechoic chambers, radiated test setups, or other controlled RF test environmentsExperience with directionality characterization, field mapping, or free-space calibration techniquesExperience with low-phase-noise LO chains, synthesizers, mixers, or frequency-conversion architecturesExperience with atomic or quantum sensors, government-funded R&D programs, or other advanced sensing applicationsTRAVEL 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.Salary range: $140,000 to $170,000100% company-paid medical, dental, vision, short/long-term disabilityEmployer-funded Health Savings AccountUnlimited PTO401(k) matchCompany-paid Life and AD&D InsuranceFlexible Savings AccountPaid FMLA, Maternity/Paternity LeaveEmployee Assistance ProgramStudent Loan RepaymentEquity Program#J-18808-Ljbffr