Microwave measurements for planar circuits and components

Short Name: PlanarCal, Project Number: 14IND02
Image showing a close up of a circuit board
Close up of a circuit board

Reliable measurements of microwave signals produced by on-wafer radio communications devices

The innovative potential of Europe’s consumer electronics, medical diagnostics, automotive, and telecoms industries has been held back by inaccurate methods available for measuring and specifying characteristics of an important enabling integrated circuit technology. Low-power ‘on-wafer’ radio communications capabilities are starting to be developed for various mobile communication devices, but these chips suffer unwanted effects due to various types of stray, or ‘parasitic’, emissions of microwave signals. Such effects become most pronounced at higher frequencies and lower signal power. The unreliability and inaccuracy of available signal measurement methods reduced market confidence in the value of device development and amplified the costs of chip fabrication.


This project developed traceable measurement and characterisation methods applicable to planar (flat) integrated circuits and components that use microwave radio frequencies, to known measurement uncertainties. As a worldwide first, traceability was demonstrated for on-wafer S-parameter (signal scattering parameter) measurements, not only for devices with built-in membrane technology but also for conventional thin-film substrates, as used in industrial applications (fused silica). Second, METAS developed the VNATools software to provide suitable measurement and uncertainty calculations. Third, guidelines for the design of calibration substrates were developed. Fourth, new instrumentation was developed to address the on-wafer measurement of nano-devices in the microwave regime.


A Best Practice Guide summarising these findings was published as Guidelines for the design of calibration substrates, including the suppression of parasitic modes for frequencies up to and including 325 GHz; and Best Practice Guide for Planar S-Parameter Measurements using Vector Network Analysers.


The process of offering a calibration service for traceable on-wafer measurements was initiated at PTB, and the first steps towards an Institute of Electrical and Electronics Engineers (IEEE) standard for on-wafer microwave measurements were made.


These outcomes enable manufacturers of planar microwave circuits and components to offer products with defensible specifications, for the first time supported by traceable on-wafer signal measurement. These methods will help increase the efficiency of mobile communication systems and reduce unwanted electromagnetic radiation emissions. The result will be faster and cheaper development of mobile communication applications, and enhanced potential for innovative solutions to be produced in this high-value European industrial sector.


EMPIR project 19SIP02 PlanarMeT builds on this work.

Project website
Influence of Microwave Probes on Calibrated On-Wafer Measurements

IEEE Transactions on Microwave Theory and Techniques

On-Wafer Residual Error Correction Through Adaptive Filtering of Verification Line Measurements

2018 International Workshop on Computing, Electromagnetics, and Machine Intelligence (CEMi)

On the Importance of Calibration Standards Definitions for On-Wafer Measurements up to 110 GHz

2018 91st ARFTG Microwave Measurement Conference (ARFTG)

Traceable Coplanar Waveguide Calibrations on Fused Silica Substrates up to 110 GHz


Noise Behavior and Implementation of Interferometer-Based Broadband VNA

IEEE Transactions on Microwave Theory and Techniques

Impact of Substrate Modes on mTRL-Calibrated CPW Measurements in G Band

2018 48th European Microwave Conference (EuMC)

Parameterization Models for Traceable Characterization of Planar CPW SOL Calibration Standards

2018 Conference on Precision Electromagnetic Measurements (CPEM 2018)

Quantitative Error Analysis in Near-Field Scanning Microwave Microscopy

2018 International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS)

A New SOLT Calibration Method for Leaky On-Wafer Measurements Using a 10-Term Error Model

IEEE Transactions on Microwave Theory and Techniques

110 GHz on-wafer measurement comparison on alumina substrate

ARFTG Microwave Measurement Symposium (ARFTG), 2017 Nov 28th - Dec 1st

Effects Degrading Accuracy of CPW mTRL Calibration at W Band

2018 IEEE/MTT-S International Microwave Symposium - IMS

Impact of parasitic coupling on multiline TRL calibration

2017 47th European Microwave Conference (EuMC)

VNA tools II: Calibrations involving eigenvalue problems

2017 89th ARFTG Microwave Measurement Conference (ARFTG)

'Mind the Gap'... Establishing Measurement Capability in the Terahertz Gap Region - from 0.1 THz to 1.1 THz

ARMMS RF & Microwave Society Conference, 13-14 Nov, 2017, Wyboston, Bedfordshire

Mutual interference in calibration line configurations

2017 89th ARFTG Microwave Measurement Conference (ARFTG)

RF wafer probing with improved contact repeatability using nanometer positioning

Microwave Measurement Conference (ARFTG), 2016 87th ARFTG

Comparison between time- and frequency-domain high-frequency device characterizations

CPEM 2016, Conference on Precision Electromagnetic Measurements: conference digest: (2016)

Characterization of high-frequency interconnects: Comparison between time- and frequency-domain methods

2016 IEEE 20th Workshop on Signal and Power Integrity (SPI) Conference Proceedings

Other Participants
Forschungsverbund Berlin e.V. (Germany)
Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. (Germany)
Friedrich-Alexander-Universität Erlangen - Nürnberg (Germany)
RF360 Europe GmbH (Germany)
Rohde & Schwarz GmbH & Co. Kommanditgesellschaft (Germany)
Technische Universiteit Delft (Netherlands)
Université de Lille (France)
University of Leeds (United Kingdom)