Patent ID: 7545151

Claim:
A method for characterizing a test fixture that is used for connecting 4 ports of a device under test (DUT) to a vector network analyzer (VNA), to thereby enable de-embedding of the test fixture from measurements of the DUT connected to the test fixture, the method comprising: (a) separating the test fixture into two 4-port test fixture segments, based on which ports of the DUT have internal coupling, wherein each test fixture segment has an outer 2-port reference plane and an inner 2-port reference plane; (b) performing a 4-port calibration at outer planes of the two test fixture segments, while corresponding ports of the inner planes of the test fixture segments are connected together with thru segments, to thereby determine a first set of S-parameters (S mn thru ); and (c) determining a set of S-parameters (S mn fixture — 1 and S mn fixture — 2 ) for each of the two 4-port test fixture segments, based on the first set of S-parameters (S mn thru ).