The on-wafer community met at European Microwave Week 2025 in Utrecht for the 22nd On-Wafer Users’ Forum. It was a great moment for engineers from across Europe. Many of them rarely meet in person. EuMW made it easy this year. The Forum brought together 29 specialists from industry, metrology institutes and universities. It offered a focused space to exchange ideas and compare real on-wafer practice.

A warm thank you goes to the EuMW-2025 Steering Committee and the Chairs. Their support made this gathering possible and helped keep the momentum of the on-wafer community strong.

Two topics dominated the discussions this year. One was the growing use of machine learning in probing automation. The other was a more practical and accessible way to handle uncertainty.

Autonomous characterization and optimization of μW transistors based on machine learning
by Olof Bengtsson, FBH, Germany
Olof presented a new adaptive probing concept. It uses an ML based bounding box to recognize the DUT size and the pad layout. This makes probe placement more robust and reduces operator dependent variation. It is a promising step toward more stable and predictable measurements.

Uncertainty in probe position compensated multiline TRL
by Robin Schmidt, Keysight, Belgium
Robin introduced a simplified way to estimate uncertainty. It avoids any coaxial or waveguide reconnections. The probes stay in place. This makes the method easy to use on both manual and automated stations. It improves measurement precision without adding extra effort to the workflow.

The Forum once again showed how quick the field is moving. It also showed how much value these informal, technical meetings bring to the European community.

Join Us at the 23rd On-Wafer Users’ Forum at ARFTG 106

We now invite everyone to continue the exchange at the 23rd On-Wafer Users’ Forum during the 106th ARFTG Microwave Measurement Symposium in Los Angeles.

Where: Loews Hollywood Hotel, Mt. Olympus Room
When: Monday, 19 January 2026
Time: 9:40 am to 11:50 am

Forum Program

9:40 to 10:00: Towards Confident Wafer-Level Characterization at mmWave Frequencies, Andrej Rumiantsev, MPI, Taiwan

10:00 to 10:20: Discussion

10:20 to 10:40: Reappraisal of S-Parameter Basics in Light of 4 port TRL de-embedding, Shuhei Amakawa, University of Hiroshima, Japan

10:40 to 11:00: Discussion

11:00 to 11:20: Overcoming RF Oscillations on RF Amplifier Devices During On-Wafer DC Testing in a High Volume Environment, Juswanto Wardojo, pSemi, USA

11:20 to 11:40: Discussion

11:50: Farewell

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About the Forum

If you are new to us, the Forum is simple. It is an informal meeting of engineers who work on wafer-level measurements and calibration. We share practical experience. We talk about challenges. We compare methods. The Forum is also a platform to form small workgroups and move ideas forward.

Our principles are clear.

Open and honest exchange
Real discussions about real problems
A friendly and informal atmosphere

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If you work with on-wafer measurements, mmWave characterization or probe-level calibration, this Forum is your place. Join us. Bring your experience and your questions. Help shape the next steps in our field.

See You in Los Angeles!

Gia Ngoc Phung,
ARFTG ExCom
Users Forums Chair

Pictures: Gia Ngoc Phung, Andrej Rumiantsev