Contactless Measurement of a D-Band On-Chip Antenna Using an Integrated Reflective Load Switch

A novel measurement setup is proposed for the contactless characterization of on-chip antennas. A D-band patch antenna is fabricated on a 100 mu m-thick GaAs substrate and is monolithically integrated with a reflective load switch to allow for fast electronic control of the antenna port termination. The antenna under test is illuminated by a reference antenna in the anechoic chamber after which the impedance and gain of the patch antenna are reconstructed from the change in backscattered field due to different port terminations. In our experiment, the over-the-air reconstructed antenna input impedance exhibits a frequency shift of less than 1% with respect to the (nonideal) on-wafer probe measurement in the 115-130 GHz frequency range. Furthermore, the measured realized gain of 0.9 +/- 0.5 dBi is close to the simulated one of 1.1 dBi.