A Mesh of Possibilities
As a Principal Engineer focused on Device Verification Testing (DVT), I helped translate signal performance into actionable results using Python, automation frameworks, and systems-level thinking.
Context: What is Terragraph?
Meta’s open-source 60 GHz wireless technology designed to deliver high-speed, low-cost internet in urban settings.
Testing this system is unique. The projects' backbone of leveraging phased-array antennas to establish an outdoor mesh network includes the addition of dealing with non-trivial interruptions from:
- beamforming
- signal integrity
- environment
Terragraph Project Overview & Facebook Connectivity Initiative
Mission: Build Scalable, Repeatable Device Testing
I was tasked with designing and automating end-to-end Device Verification Testing (DVT) for pre-production phased-array antennas.
This entailed developing comprehensive Python automation suites for:
- RF beam calibration and sweep tests.
- Spectrum analyzer integration (via PyVISA, SCPI commands).
- Cross-checks of antenna gain patterns and noise floor response.
- Data visualizations for heatmaps, antenna patterns, performance analyis.
- Multi-device orchestration with parallel programming patterns
Documentation That Mattered
I authored internal design specs that defined what "passing units" on the production floor meant, including:
- Antenna alignment and performance tolerances.
- Power output ranges and spectral purity.
- Integration test protocols for mesh behavior and thermal tests.
- Device bring-up docs and low-level hardware flashing.
These documents became reference standards used by hardware teams across continents.
Data-Driven Debugging
- Used Python to parse and visualize gigabytes of performance logs, network connectivity, and interference.
- Automated time-correlated plots comparing RF output vs. control signal logs for deeper root-cause detection.
- Provided actionable insights to domain experts in timely manner with data visualization and presentations
Global Impact: Taiwan Training & Manufacturing QA
- Flew to contract manufacturing facilities in Taiwan.
- Delivered hands-on training to QA and test engineers.
- Introduced Python-based test workflows to replace error-prone Excel macros.
- Unified test scripts across remote sites (US, APAC).
Achieved a reduction in test failure rates by over 50% within 3 months.
Reflections
- RF testing includes art + engineering, especially at 60 GHz, which I love.
- Working on Terragraph prepared me for my later AR/VR roles (low-level measurement, large-scale automation, cross-team validation).
Automation isn't just faster testing, it's repeatable knowledge transfer at scale.