Development of a Low-Cost Probe based on the SMA Adaptor for S-Parameter Measurement

To measure the S parameters of a connector directly is not easy. Usually, a test fixture with soldered SMAs or similar adaptors is needed. Then the measurement results of S parameters will include the effects of the SMA adaptors and the traces of the test fixture. The objective of this research was to develop low-cost probes to measure the S parameters of the connectors directly. We modified the SMA socket to socket (reverse polarity) type adaptors to make two probes, and the probes' effects can be calibrated using the standard SOLT calibration kit. The experimental results showed that at least one probe performed equivalently as a microwave probe up to 10 GHz measurement in insertion loss and return loss.