A Calibrated Over-the-Air Measurement Method for Error Vector Magnitude Characterization

Error vector magnitude (EVM) is one of the key parameters to quantify the performance of a digital radio transmitter or receiver. However, the measurement method of EVM has not been formed properly, especially for those devices with integrated antenna, e.g., antenna in package (AiP). This article proposes a way for EVM test through the over-the-air (OTA) measurement method. First, the concepts of EVM and OTA measurement methods are reviewed; then, the composition of EVM in OTA measurement is analyzed; next, experiments are performed based on the proposed calibration method; finally, the measured results are gated and compared to those results based on traditional conductive measurement methods. The compared results indicate that our proposed method is technically feasible and has high accuracy for those devices with integrated antennas.