- The Electronics and Telecommunications Research Institute (ETRI), a South Korean research institute, has established a characterization platform for GaN MMICs (Gallium Nitride Monolithic Microwave Integrated Circuits) based on Anritsu’s VectorStar ME7838G vector network analyzer (VNA).
- The platform is intended for on-wafer measurements of devices operating in the millimeter-wave and sub-THz frequency ranges, with coverage of up to 220 GHz in a single sweep.
The development of GaN components for high-frequency applications requires their behavior to be characterized over a broad frequency range. ETRI reports that its measurements cover not only the device’s operating band, but also its harmonic frequencies, in order to compare measured characteristics with design results.
Measurements directly on the wafer
To characterize GaN MMICs before packaging, ETRI uses on-wafer measurements performed directly on the wafer or substrate carrying the circuits. This approach makes it possible to measure the device before it is integrated into a package and to prevent effects associated with packaging and mounting from being included in the measurement results.
At these frequencies, however, on-wafer probing introduces additional sources of uncertainty. The contact between the probes and the pads of the device under test must be controlled, while the characteristics of the measurement system can also affect the results. These effects can lead to variations between measurements and make it more difficult to compare experimental data with simulations or design results.
The objective of the platform established by ETRI is therefore to characterize devices over a wide frequency range while maintaining common measurement conditions as far as possible.
Coverage up to 220 GHz with a single system
The VectorStar ME7838G vector network analyzer can perform measurements in a single sweep up to 220 GHz. ETRI can therefore characterize devices from the millimeter-wave frequencies through the sub-THz range without changing measurement systems between different frequency bands.
This architecture also eliminates the need to transfer the same device between several instrument configurations when its characterization covers multiple frequency ranges. The resulting data can therefore be compared under common measurement conditions.
For GaN MMICs, this frequency coverage makes it possible to study both the operating band and the harmonic components of the signal. The measured parameters can then be compared with design data to verify device models and expected behavior.
