Broad-band test devices

Non resonant techniques are only of limited use to determine microwave losses with high precision, in particular when the losses are very small. Flowever, for the investigation of nonlinear absorption phenomena (i.e. rf power dependent on surface impedance or loss tangent) by intermodulation distortion measurements broad-band test devices are more common. Typically, a planar transmission line with an impedance of 50 Ohms can be employed for intermodulation... 

In many modern laboratory accelerated test devices, the irradiance in watts per square meter (W/m ) in a specified spectral range is photometrically monitored and the lamp power is automatically adjusted to maintain constant irradiance. In xenon arc devices, it is commonly controlled at either 340 nm, referred to as narrow band control or over the full uv, 300-400 nm, referred to as broad... 

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