Study on antenna radiation electric field and coupling of microwave heating asphalt mixtures

A single-antenna radiation electric field model and a radiation coupling electric field model between antennas are established to study the impacts of coupling on antenna radiation electric field during the microwave heating of asphalt mixtures. Radiation electric and temperature fields are simulated. Results show that the electric and temperature fields are not uniformly distributed when asphalt mixtures are heated with a single antenna. Two symmetrical regions with fairly high electric field intensities exist on the surface of the asphalt mixture. The temperature field of the asphalt mixture follows an elliptical distribution, with the temperature reaching maximum value at the centre and decreases away from the centre. The electric and temperature fields are large at the separatrix of the antennas when the asphalt mixture is heated with the coupling antennas with no gap between the antennas. Moreover, the electric and temperature fields of the asphalt mixtures have poor distribution uniformity. Maintaining certain antenna spacing can improve the uniformity of field distribution.