3D radiation pattern measurements of miniature antennas

Accurate measurements of radiation patterns in the full spherical format are of great importance to the research on small antennas for terminal applications. The measurement method should provide main features of radiation patterns and derive value of radiation efficiency. The described in-house developed system for measurements of 3D radiation patterns uses a positioner made solely with dielectrics. The developed software to run the measurement procedure, enable determination of the radiation efficiency with the direct approach by integration field components onto the spherical radiation pattern. The measurement methodology eliminates one of main error sources which is a cable used to feed measured small antennas. In our approach, use is made of a built-in signal source, typically a VCO oscillator powered with batteries. When only data on radiation efficiency are needed accurate determination of its value can be made with 3D radiation pattern known on four to eight equally spaced cut-planes.