Specifications

3-7-1. Agilent supplied RF test fixtures
Agilent Technologies offers various types of RF test fixtures that meet the type of the DUT and
required test frequency range. Consider measurable DUT size, electrode type, frequency, and bias
condition to select a suitable test fixture.
There are two types of RF test fixtures: coaxial and non-coaxial test fixtures, which are different
from each other for both geometrical structures and electrical characteristics. As the non-coaxial
test fixture has open-air measurement terminals as shown in Figure 3-14 (a), it features ease of con-
necting and disconnecting DUTs. The non-coaxial type is suitable for testing a large number of
devices efficiently. Trading off the benefit of measurement efficiency, the measurement accuracy
tends to be sacrificed at high frequencies because discontinuity (miss-match) in electrical character-
istics exists between the coaxial connector part and the measurement terminals. The coaxial test
fixture holds DUT using similar configuration to the coaxial terminations, as shown in Figure 3-14
(b). The DUT is connected across the center electrode and the outer conductor cap electrode of the
test fixture. With 50 Ω characteristic impedance maintained continuously from test port to the
DUT, the coaxial test fixture provides the best measurement accuracy and the best frequency
response. As the diameter of its replaceable insulator can be selected to minimize the gap between
the DUT and the insulator, the DUT can be positioned with a good repeatability across the test fix-
ture’s terminals independently of operator skill. The coaxial test fixture ensures less additional
errors and much better measurement repeatability than the non-coaxial test fixtures.
Figure 3-14. Types of RF impedance test fixtures
3-14