The present disclosure involves method and apparatus for de-embedding test fixture to extract the electrical behavior of device under test. A calibration board with both “1× open” and “1× short” test structures is fabricated and measured by equipment such as vector network analyzer that produces S parameters. The S parameters of “1× open” and “1× short”, with or without correction factors, are combined to produce the S parameters of equivalent “2× thru” test structure. The S parameters of equivalent “2× thru” are used subsequently to de-embed the test fixture. This present disclosure gives a simpler and more accurate method to create the S parameters of “2× thru” for de-embedding.