Efficiency Measurement of Connected Arrays Using the Improved Wheeler Cap Method

We present a method for measuring antenna efficiency of connected arrays. The method is a modified version of the improved Wheeler cap (IWC) method where the antenna under test (AUT) is electrically connected to two walls of the Wheeler Cap which simulates array connection. Theoretical analyses based on plane wave and cylindrical wave problems and numerical simulations using HFSS and FEKO are presented to establish accuracy estimates for the method. Close attention will be made in comparing two data collection techniques: frequency sweeping versus wall shifting. Finally, we discuss an apparatus for efficiency measurement of a 1-D connected array and the measurement results.