CALIBRATION OF ELECTRIC COAXIAL NEAR-FIELD PROBES AND APPLICATIONS

A new calibration technique for application to nearfield probes has be en developed. For this, a simple electric coaxial near-field probe for application in the 0.05-20-GHz band has been developed, theoretically analyzed, and calibrated using a known field, By using the finite-dif ference time-domain (FDTD) method, this field probe is theoretically a nalyzed to determine its most sensitive probe segment. Taking the ampl itude of the normal electric field at this segment as a known field, t he probe is calibrated by defining a performance factor (PF), which is the ratio of the known field amplitude to the probe signal amplitude, Comparing the calculated results with measured results, the agreement is good. Additionally, the measurements are experimentally characteri zed with respect to the influence of the distance between the probe an d the device-under-test (DUT), the influence of the input signal on th e probe, and the spatial resolution. Two measurement examples are demo nstrated, which investigate the mode and field distribution within pas sive coplanar microwave components.