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7percent Ventures
7percent Ventures

Principal Radio Frequency Engineer



El Segundo, CA, USA
Posted on Sunday, June 16, 2024

About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production at scale. We’re designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Principal Radio Frequency Engineer

Castelion is seeking a high output RF Engineer to lead the design and development of RF communications hardware & telemetry systems (both front end and back end) for Castelion hypersonic test platforms and weapon systems. In this role you will be responsible for initial vehicle telemetry systems for Castelion hypersonic test flights and lead software defined radio (SDR) product development for Castelion weapon systems. The role will coordinate closely with Castelion’s engineering leadership and report directly to the Head of Avionics. A successful candidate will have significant experience delivering highly manufacturable RF/avionics hardware with extreme reliability for mission-critical applications in a fast-paced environment.


  • Test Radio Development. Rapidly implement a scrappy telemetry system for high cadence flight testing based on widely available (not supply constrained) equipment and successfully capture Castelion flight tests before the end of Q2 2024
  • Flight Radio Development. Work with Castelion vehicle engineering to deliver a successful software defined radio communications system. In this role, rapid development is needed to meet company objectives, which includes: a complete RF system design completed within 3 months of the start date, followed by a working end to end prototype within 6 months of the start date. A flight demonstration of the entire system is expected late Q4 2024
  • Telemetry System Development. Work with Castelion vehicle engineering to deliver a successful telemetry and command system. In this role, rapid development and collaboration is needed to meet company objectives, which include multiple test flights. To meet company test flight cadence, the candidate should expect to complete telemetry system prototype design within 3 months of the start date, followed by a working end to end prototype within 6 months of the start date, or before the Q3 2024. A flight demonstration of the entire system is expected late Q4 2024.
  • Lead Team in Fast-Paced Environment. Lead design reviews and system architecture reviews for RF avionics system and sub-systems. Demonstrate daily/weekly cadence of development progress and prototype design cycles every four weeks. Complete design and requirement reviews ahead of build and capture value from extremely high cadence testing and prototype builds.
  • Implement and Manage Castelion Avionics Standards including modeling, PCBA rules, derating, and naming conventions. Responsible for building out quality/reliability standards including EEE part sourcing and acceptance/qualification testing of your designs.
  • RF Flight Hardware Experience. Demonstrated ability to design, order, and integrate flight RF systems, from initial link budget to scaled production. Experience or clear understanding of how to design TT&C systems front/back end and scale production in a representative environment. Experience with software defined radio development and implementation.
  • Avionics Design. Demonstrated ability to execute avionics system design, schematic capture, layout, bring up and high cadence HITL test campaign. Experience bringing up your own RF designs, including successful flight operations. Awareness to know how/when to pull in other engineering input vs. when to decide on a plan of action and move forward.
  • Full Life-Cycle Development. Ability to creatively solve problems and weigh against multi-disciplinary requirements together while assessing risk and making design and development decisions. Understanding of electrical schematics and electronics manufacturing to analyze and improve test coverage. Hands-on experience with sizing, installing and troubleshooting various electronic components. Experience with RF harness design and build, including associated sub-components.

Basic Qualifications

  • Bachelor’s degree in computer engineering, electrical engineering, or related field.
  • 5+ years of experience RF engineering
  • Experience with modeling/analysis tools/software such as HFSS, CST, ADS, MATLAB, C/C++, and/or Python
  • Experience with RF test equipment such as VNA, spectrum analyzer, etc
  • Experience creating and maintaining link budgets and analysis related to communications or remote sensing systems
  • Experience with field testing RF systems in remote environments

Preferred Skills and Experience

  • Graduate degree in electrical engineering with emphasis in microwave/RF engineering
  • 5+ years of professional experience in a relevant field
  • Experience designing RF systems including radio astronomy, SIGINT, ELINT, radar, or wireless communications
  • Experience modeling RF and channel impairments such as multipath, phase noise, group delay, fading and nonlinear distortion
  • Experience with basic principles of antenna theory
  • Experience with software-defined radios and frameworks, such as GNU Radio

Additional Requirements

  • Willing and able to work extended hours and/or weekends with minimal notification to meet critical deadlines leading up to major milestones.
  • Able to travel up to 10% on an ongoing basis

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

Leadership Qualities

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.

ITAR Requirements:

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.