Radiation efficiency of slot antenna at 60 GHz

The radiation efficiency is one of the most difficult antenna parameters to estimate accurately from physical measurements, and it becomes even more difficult for high efficiency antennas at mm-wave frequencies. But numerical experiments can be trusted if the material parameters are known with sufficient accuracy, which is the case for most metals. We determine the radiation efficiency of one of the most fundamental antennas, the short (half wavelength) slot, for the mm-wave frequency of 60GHz. The increasing radiation efficiency with the slot width and metal thickness is presented graphically. The outcome is design guidelines for maintaining the high efficiency of the slot as an element and as an array on the broad wall of waveguide. For on-chip antenna fabrication of mm-wavelength antennas, this guideline allows the time and cost of the sputtering process to be minimized.