An Overview of Probe-Based Millimeter-Wave/Terahertz Far-Field Antenna Measurement Setups [Measurements Corner]

In recent years, there has been great interest in millimeter-wave (mmwave) and terahertz (THz) technologies due to an increasing demand for ultrahigh data transfer rate. Two novel solutions, i.e., antenna on chip (AoC) and antenna in package (AiP), have been proposed for the development of highly integrated radio and radar systems [1]-[5]. To measure the antenna characteristics of AoC and AiP, a reliable probe-based mm-wave/THz antenna measurement setup became essential. Over the last 20 years, the world has witnessed the prosperous development of various mmwave/THz antenna measurement setups, most of which can be divided into two types, i.e., probe-station and quasi-in-air based. The former type has a feature that allows the testing equipment to be compactly established on a large metal stage, which has been widely used for near-field based and as part of the farfield-based setups [6]-[10]. The antenna under test (AUT) is maintained on a wafer chuck placed on the stage and thus, only the radiation pattern in the upper half-space is measurable due to the metal stage obstruction. The latter type reduces the defect by using an extended supporting structure to hold the AUT in midair away from the stage so that the radiation patterns in both the upper and lower half-spaces are measurable. Many setups of this type measure antennas at far-field distances, and some of them are also compatible with near-field testing. Compared to probe-station based, quasi-inair based takes up much more space and is less compact.