ICM High Power Test Fixture System assembled
The ICM High Power Test Fixture is very flexible to
test many different package sizes quickly and
economically. Individual components can be
interchanged to accommodate specific test
applications. The launch sections can be in 50 ohms
or can have pre-matching circuitry. The fixture can be
operated with air or liquid cooling. The Heatsink can
be removed to mount the test fixture onto a hot-cold
plate for environmental control.

High Power Test Fixture System exploded
The ICM High Power Test Fixture is assembled from
individual components which are chosen for the
specific test application. To test different packages
only the midsection has to be changed if the transistor
has the same tab width. To accommodate different tab
width the microstrip launch sections can be
interchanged. Different connector options are
available for the Transition Assemblies. All
components are mounted onto the Base & Heatsink
Assembly.

TRL Calibration Standards
Calibration should be done inside the fixture in order
to eliminate the influence of the test fixture
(de-embedding). The TRL Standards are available for
50 ohm and lower impedances such as 11.3 ohms.
The Standards have to be compatible with the tab
width of the DUT and the microstrip launches in
order to get a good calibration. Different material
have to be considered to physically realize the
microstrip launches and the calibration standards.
Complete calibration coefficients are supplied with
every fixture.

High power test fixtures are used mainly in two different
configurations:
1) 50 Ohm environment:
The first application is that Transistor packages are measured in a
50-ohm environment in order to establish the parasitic of the
package.
Internally matched transistors are also measured in a 50-ohm
microstrip environment.

2) Pre-matched environment:
The second application is to measure packaged devices with
matching circuits at the input and the output.
Quarter wavelength matching circuits are often used to present a
lower impedance to the Device Under Test (DUT).

The Transistor to be tested is mounted onto a Midsection
Assembly which has the proper width and mounting heights for
the specific package to be tested.

The size of the package leads at the input and output has to be
considered when selecting the Microstrip Launch Assemblies to
avoid discontinuities from the launching circuit to the package.
Select to use either a 50 Ohm microstrip launch or a matching
circuit for you specific application.

The Pusher Assembly will press the Transistor lead securely onto
the microstrip. The width of the pusher section matches the
transistor tab width.

Select a Transition Assembly with the the desired connector style
and an RF-pin size to properly match to the Microstrip size of the
selected Microstrip launch assembly (see table).

Base plate and Heatsink

Calibration should be done inside the fixture in order to eliminate
the influence of the test fixture (de-embedding). TRL Calibration
standards are available for 50 ohms and for lower impedances
such as 11.3 ohm. Different standards are needed for the different
package lead width e.g. lead-width of 500 mil, 225 mil etc.