Analysis and Design of a Compact Leaky-Wave Antenna for Wide-Band Broadside Radiation

A low-cost compact planar leaky-wave antenna (LWA) is proposed offering directive broadside radiation over a significantly wide bandwidth. The design is based on an annular metallic strip grating (MSG) configuration, placed on top of a dual-layer grounded dielectric substrate. This defines a new two-layer parallel-plate open waveguide, whose operational principles are accurately investigated. To assist in our antenna design, a method-of-moments dispersion analysis has been developed to characterize the relevant TM and TE modes of the perturbed guiding structure. By proper selection of the MSG for a fabricated prototype and its supporting dielectric layers as well as the practical TM antenna feed embedded in the bottom ground plane, far-field pencil-beam patterns are observed at broadside and over a wide frequency range, i.e., from 21.9 GHz to 23.9 GHz, defining a radiating percentage bandwidth of more than 8.5%. This can be explained by a dominantly excited TM mode, with low dispersion, employed to generate a two-sided far-field beam pattern which combines to produce a single beam at broadside over frequency. Some applications of this planar antenna include radar and satellite communications at microwave and millimeter-wave frequencies as well as future 5G communication devices and wireless power transmission systems

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 2x2 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 degrees 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)