On-wafer probes for submillimeter-wave on-chip antennas

On-chip antennas (OCAs) have been widely used in millimeter and submillimeter MMICs due to the packaging issue and applications. However, it is difficult to measure OCA field patterns with standard horn antennas while path losses are severe. As both near- and far-field measurements are essential for OCAs, we propose an on-wafer probe design with a miniature horn antenna to efficiently examine OCAs. The greatest advantage is that the probe is so compact to minimize the interference from other DC or RF on-wafer probes. We have designed and tested three antenna probe prototypes at 140-220, 330-500 and 500-750 GHz frequencies to demonstrate the feasibility. The measurement results suggest that path losses at submillimeter wavelengths are critical and the compact antenna probes are powerful tools for submillimeter OCAs.