01
Handed to me
SAR testing: measuring how much radio-frequency energy a phone puts into the body, test after test, band after band.
UL Solutions · Fremont, California · May – Aug 2025
My first summer at UL: learning the kit, then fifty tests in a day.
I was a SAR & Data Engineering intern. SAR is how much radio-frequency energy a phone puts into the body. I learned to measure it on DASY6 and SPEAG equipment, and one day I ran fifty tests, the most any intern in the company’s history has done in a day.
SAR & Data Engineering internDASY6 · SPEAG50 tests in one dayCame back in 2026
Test requests · samplein the order they came
What’s measured. A phone transmits against a model head or body (a phantom) filled with liquid, and a probe maps how much of its energy that liquid absorbs. Every band and position is its own test.
One lab day · 09:00 – 17:00
setuphead phantomflat phantom
0 tests fit in the day
Each test needs setup, then measuring. Setup depends on what came before it.
Sample tests, minutes and setup rules, made up for this page to show why order matters: changing the phantom takes longest, moving the phone takes a while, changing the band is quick. It is not UL’s procedure and not a record of how my fifty-test day went.
What the summer looked like
Four parts, in the order they happened.
02
Learned
Electromagnetic communications testing, the SAR measurement protocols, and the DASY6 and SPEAG equipment they run on.
03
One day
50 tests
in a single day, the highest by an intern in the company’s history.
04
Then
I came back the next summer as a product management intern, looking after five labs. See 2026 →
The rest of the job
The parts a record doesn’t show.
- The scienceElectromagnetic communications testing, and why a phone’s position and band both change what it puts into the body.
- The protocolsSAR measurement protocols: how each test has to be set up and run.
- The equipmentDASY6 and SPEAG systems, the equipment every test ran on.
- The next summerBack at the same site in 2026, this time as the first point of contact for five labs and building their internal tools.
Honest limit: the demo above is a made-up day to show that order matters. The real tests, devices and results belong to UL and its clients.