Improved Measurement Accuracy of Probe-Fed mm-Wave Antennas Using the Three $\Gamma$ Method

In this letter, we present a method to extract the scattering parameters of a microelectronic probe used to feed on-chip or in-package antennas at millimeter-wave frequencies. It is especially important to take into account these losses in the calibration procedure necessary for the extraction of the antenna gain. We are specifically demonstrating that these losses are positively or negatively impacted, depending on the impedance value of the input impedance of the antenna connected to the probe. Theory is detailed and examples are given to illustrate the importance of taking into account those losses with precision. From the S-parameters of the probe and the measurement of the reflection coefficient of the antenna, we can compute the gain from the measured realized gain. An accuracy improvement of 15% is shown for the gain of the presented antenna.