VIDEO TRANSCRIPT:

If the measurement plane is different from the calibration plane, embedding, de-embedding, and port extensions can help compensate for the loss caused by the additional fixture. These functions are usually a built-in function for most VNA software. Embedding and de-embedding have proven to be the most accurate way to remove or add any additional circuitry as the fixture is mathematically included or excluded with the help of a touchstone file. In these touchstone files there are S-parameter values at various frequency points and by referring to the data in this file the software can accurately calculate the fixture effects and then remove them from the measurements. There is also a simpler way to de-embed a fixture with the help of the port extension function. This function virtually extends the test ports by moving the calibration plane to the terminals of the DUT. This is done by adding an electrical delay and it assumes that the transmission line is lossless. Therefore, if you see any ripples due to mismatches then using a touchstone file would be a better method for de-embedding. These days we also have an auto port extension option available which allows for automatic calculation of port extension parameters by measuring a short or open standard. The result of the auto port extension function is actual the calculation of the electrical delay value. Once the de-embedding function is performed the measurement plane moves towards the plane of the DUT.