Optimized Antenna for Asphalt Mixture Recycling based on Microwave Heating

To improve the uniformity of the temperature and electromagnetic fields of asphalt mixtures heated by microwaves, the structure of a horn antenna is examined. The length and width of the feed waveguide are calculated as 85 mm and 55 mm, respectively, according to waveguide theory. The height of the antenna only slightly influences gain distribution according to the radiated electromagnetic field. The length-width ratio of the aperture plane of the antenna affects the uniformity of distribution of the electromagnetic field. When the ratio is the same as that of the feed waveguide, the gain of the electromagnetic field is the most evenly distributed. The farther the ratio deviates from that of the feed waveguide, the more intensively the electromagnetic field transmits. However, the simulation result indicates that the antenna with the most uniform distribution of electromagnetic field reflects the most energy.