Hurdles to on-wafer harmonic measurements

With the ever increasing need for spectrum the mobile phones, specifications are tougher for spurious emissions. Harmonics can fall into bands that are used for other services so prior evaluation of those harmonics is critical in product development. An on-wafer harmonic bench is used for fast evaluation of material and designs without having to build a final product to predict what the harmonic performance will be. Harmonic measurements are not new; but high power (4 watts), on-wafer harmonic measurements present hurdles that have not been solved. Low passive intermodulation (PIM) components, probe selection, connector selection and bench configuration all play into building a measurement system with low enough system noise to be able to evaluate the state-of-the-art technologies for mobile applications.