Dual-polarized probe with full octave bandwidth and minimum scattering for planar near field measurements

Dual-polarized probes with wide-bandwidth operational capabilities are highly desirable for time-efficient Planar Near-Field (PNF) measurements [1]-[3]. However, sometimes the performance tradeoffs necessary to achieve the desired operating bandwidth make such probes impractical for many applications. Traditional probes are often bandwidth limited, and their electrical size can be an undesired source of scattering in PNF measurements, in particular if the probe-AUT distance is small [4]-[5]. An innovative, octave-band probe has recently been presented combining wide bandwidth, near constant directivity, low cross-polarization, and minimum scattering [6]. In this paper, the probe design is discussed in detail, including technical and implementation trade-offs. Several probes have been manufactured at L/Ku-band band, and test results are presented. The probe design is fully scalable, even beyond Ka-band. The scattering properties of the probe (in terms of measurement perturbation) are assessed by numerical simulation and compared to standard rectangular open-ended waveguides.