Measurement Uncertainties in Millimeter Wave fiOn-Chipfl Antenna Measurements

As a result of recent technical and regulatory developments, the millimeter wave (mmw) frequency band (30GHz – 300 GHz) is being adopted for a wide range of applications. Based on array signal processing technologies used for 4G and MIMO, companies are developing small active array antennas operating throughout the millimeter-wave bands. These arrays may include radiating elements and feed structures that are a fraction of a millimeter in size and cannot be fed via a coaxial cable. Connection to the antenna is instead performed through a micro-probe, more commonly used in the chip industry. MVGOrbit/FR has developed a compact antenna measurement system which integrates hardware and software necessary to provide antenna gain and radiation patterns of antennas fed with such a micro-probe. To evaluate uncertainties in the measurements of the Antenna Under Test (AUT) gain, directivity, efficiency, pattern, or VSWR, reference antennas are an invaluable tool. The authors have recently driven the development of a micro-probed chip reference antenna. This reference antenna was designed to be mechanically and electrically stable and with reduced sensitive to its mounting fixture and feeding method. Close agreement between measured and simulated characteristics has been achieved. With low losses, the antenna provides good dynamic range and confidence in the measured antenna efficiency and gain. This paper will outline design requirements and present test results of 60 GHz Chip Reference antennas. Several dozen antennas have been tested. The related uncertainties in the microprobed antenna measurements will be evaluated with particular emphasis on the gain calibration uncertainty. The paper will also describe the next steps towards developing a chip antenna gain standard, that should reduce gain uncertainties while also significantly simplifying the calibration process.