A system for analyzing a probe card comprises a signal generator adapted to generate a radio frequency test signal. a connector for inputting into the probe card the radio frequency test signal, and a detector assembly. The detector assembly comprises an RF chuck for receiving a radio frequency signal from the probe card, and a sensor configured to receive the radio frequency signal from the RF chuck. The sensor is configured to measure a magnitude of the radio frequency signal and to output a measurement signal that represents only the magnitude of the radio frequency signal. The RF chuck and the sensor are mechanically coupled.