Near-field characterization of parasitic and slotline mode coupling in a quasi-optical unit cell via electro-optic sampling

The nature and degree of electromagnetic coupling in a passive quasi-optical transmission grid amplifier unit cell are investigated from an experimental point of view by employing electro-optic sampling. Parasitic coupling within a CPW-based folded slot structure is observed to peak at -14 dB. Coupling of incident-wave energy through the CPW transmission line interconnect is directly determined by the near-field measurement technique to occur via a slotline mode.