Principal Antenna Engineer

Kapta Space, a VC-funded early-stage startup in Seattle, WA, is breaking new ground in Geospatial Intelligence. Our technology centers around a proven, scalable electronically-steered radar for sophisticated spaceborne applications such as earth observation using synthetic aperture radar (SAR) techniques, as well as enabling advanced defense missions such as target tracking on the ground and in the air.

Kapta is seeking a Principal Antenna Engineer to lead the development of our radar antenna systems. The antenna engineer will be responsible for design, build and test of high frequency and millimeter wave electronically scanned antennas in collaboration with diverse engineering disciplines. This position requires a strong, self-driven engineer capable of working in a fast-paced, multi-disciplinary environment.

• Assist multi-disciplinary team in translating radar performance into antenna requirements, architecture, interfaces, and design trades.
• Design high-performance antenna systems and microwave circuits for use in c-SWaP-constrained systems.
• Develop tools for antenna and RF performance analysis within the larger radar system.
• Drive antenna hardware development efforts, working closely with vendors and suppliers to meet performance, cost, and schedule objectives.
• Test what you build! Take measurements and perform analysis of antenna and radar systems. Incorporate test data into system-level performance analysis.
• Optimize and calibrate antennas and antenna arrays for key performance metrics, including gain, side lobes, scan performance, bandwidth, and polarization purity over frequency and scan angle.
• Model array gain, scan loss, coupling, sidelobes, polarization, and spacecraft effects in HFSS/CST/FEKO.
• Build, test, and mature antenna, feed, and RF prototypes; partner with suppliers through qualification and production readiness activities.
• Support near- and far-field antenna test campaigns, leveraging measurement results to validate EM simulations, refine antenna designs, and assess radar system performance.
• Develop array calibration, beam-steering, and alignment methods with FPGA/DSP/software/RF teams.
• Optimize gain, efficiency, sidelobes, polarization, isolation, and phase/amplitude accuracy over scan.
• Support spacecraft integration and RF qualification across thermal, vibration, and thermal-vacuum environments.
• Drive technical problem solving, design reviews, and hardware maturation from early prototypes through flight-ready products.
• Develop, implement, and validate antenna control algorithms for advanced performance modes.
• Contribute to recruiting, interviewing, and hiring efforts to support team growth.

• BS, MS, or PhD degree in electrical engineering, electromagnetics, physics, or a related discipline.
• Onsite role in Redmond, WA.
• 10+ years of RF/antenna development, including phased arrays for radar or communications.
• Strong array theory: impedance matching, coupling, polarization, scan behavior, and beamforming.
• Proven track record of designing creative antenna systems that successfully balance multi-disciplinary engineering requirements.
• Familiarity with high-density PCB-based antenna design and fabrication
• Experience with phased-array design principles and digital beamforming (DBF)
• Proficiency with HFSS/CST/FEKO and Python/MATLAB for analysis, test automation, and model correlation.
• Hands‑on VNA, spectrum analyzer, signal generator, and near-/far‑field antenna measurement experience.
• High-frequency/mmW PCB antennas, feeds, waveguide/passives, prototyping, and strong cross‑functional ownership.
• Demonstrated ownership of complex technical challenges from concept through implementation, validation, and deployment.

• Spaceborne phased‑array/radar antenna design, spacecraft integration, and environmental qualification.
• Radar experience, especially SAR, GMTI/AMTI, performance analysis, high‑power RF, or digital beamforming.
• Meta material, traveling‑wave, leaky‑wave, or other low‑profile electronically scanned antenna architectures that balance performance vs cost.
• RFICs, beam former ICs, custom ASICs, T/R modules, or…