Millimeter-wave frequencies are being increasingly used in automotive electronic safety systems and are proposed as available spectrum for wideband data links in emerging 5G wireless communications networks. Frequencies at 30 GHz and above require smaller antennas due to the smaller wavelengths, and testing those antennas can be challenging.
Fortunately, researchers from Ulm University in Germany have considered the need for those measurements. They have developed a test system based on a commercial vector network analyzer (VNA) and a robot controller for changing the positions of antennas under test. The flexible measurement system was designed in various configurations for measurements to 60 GHz in one case and as high as 110 GHz in another. In addition, the researchers mention the availability of wafer probers for on-wafer measurements through 325 GHz.
The test system was demonstrated for both near-field and far-field measurements using a horn antenna operating at 280 GHz. Error analysis was performed to quantify the accuracy of the test system and develop an error budget, and the system’s enhanced accuracy was shown for measurements of an integrated antenna at 160 GHz with measurement uncertainly of an impressively low 0.3 dB. Excellent agreement was found between computer-simulated results and the test data achieved with the millimeter-wave antenna measurement system.
See “The Challenges of Measuring Integrated Antennas at Millimeter-Wave Frequencies,” IEEE Antennas & Propagation Magazine, Vol. 59, No. 4, August 2017, p. 84.