Remote Microwave Sterilization Applicable to Coronaviruses Using a Van-Atta Retrodirective Antenna Array with 2-D Tracking Capability

We propose a method for remote sterilization of surfaces which follows wireless power transmission principles. Using the self-steering tracking capability of retro-directive arrays (RDAs), an infected area of interest can be sterilized by radiating microwave power in a controlled and efficient manner, thus producing heat for pathogen deactivation. The employed antenna array system offers dual-circular polarization with isolation values of 55 dB which supports the co-location of the transmit and receive parts of the RDA. In particular, the paper reports the use of a 2 x 2 circularly polarized RDA system operating in the S-band, which is used to investigate the possible heat change of a water covered sample for sterilization, placed at different ranges from the transmitting point and rotated in the plane normal to the illumination. The time required to heat the area of interest up 60°C is numerically studied and the capabilities of inducing the needed temperature gradient over the samples is examined. In addition, measurements have been performed using biological samples of the coronavirus (strain Cov-229E-GFP) to demonstrate virus deactivation. The proposed methodology can also be made completely automated and with little operator interaction, representing a new and attractive option for microwave sterilization of pathogens such as those related to the severe acute respiratory syndrome coronavirus (SARS COVID-19).