Electro-optic measurement technique for millimetre wave antennas

The development of high speed devices and materials for millimetre wave integrated antenna systems has sustained a need for ever faster and more flexible measurement systems. Several methods of performing time and frequency domain measurements of antenna near-field patterns and substrate electric fields exist using electro-optic sampling (EOS). An important feature of electro-optic sampling in antenna applications is its ability to directly measure the vector current distribution and mutual coupling effects on the antenna metallization. This technique promises to generate and measure pulses that have frequency ranges to the THz region, as compared with vector network analyzers that are limited to approximately 100 GHz and require electrical connections to the device being tested. We review electro-optic sampling techniques and their potential as a new “network analyzer” for the antenna engineer, enabling measurements to the 200 GHz range with a spatial resolution of micrometres. Initial experiments performed through a joint research program between the Ontario Laser Light Research Institute of Ontario (OLLRC) at the University of Toronto, and the Communications Research Laboratory (CRL) of McMaster University, are presented that demonstrate that the EOS technique is indeed a strong candidate for the measurement of millimetre wave antenna systems.