An Ultra-Wideband Plane Wave Generator for 5G Base Station Antenna Measurement

Plane-wave generators (PWGs) for over-the-air testing of 5G base stations offer the advantages of efficiency and economy. Many new bands, such as n28, are progressively being introduced, driving the bandwidth improvement of PWGs. The cost of amplitude-phase control networks is also increased by the broadband range required for testing. In view of the above challenges, in this paper, a low-frequency ultra-wideband PWG for testing 5G base stations is reported. Firstly, an electrically small antenna unit based on the Vivaldi antenna is design for the PWG. The antenna unit has a wide operating band and compact size, allowing it to reach a quarter of the minimum frequency wavelength. Then, the operating band from 700 MHz to 4 GHz is divided into three sub-bands, and the amplitude and phase excitations within each sub-band are optimized with multiple frequency points. Finally, the designed ultra-wideband PWG is simulated and experimentally tested. The designed 2.64 m one-dimensional linear-array PWG is able to produce a 1.5 m x 1.32 m quiet zone with less than 1.0 dB and 10 degrees. The results of the radiation pattern measurements for the base station agree reasonably well with the MVG SG128.