Waveguides for long-distance energy transport in microwave heating

© 2016 International Microwave Power Institute. Performance of waveguides for long-distance energy transport in microwave heating was evaluated by comparing the microwave propagation characteristics, including maximum transmitted power Ptrans, attenuation constant α and percentage of power loss ploss proposed in this study, of commercially available rectangular waveguides (WRs) constructed of various metals (Ag, Cu, Ag, Al and Fe) for microwave heating at 0.915 and 2.45 GHz with those of different types of circular waveguides, namely circular waveguides with the same cut-off frequency as rectangular waveguides (denoted by WCFs), circular waveguides with the size equal to rectangular waveguide (denoted by WCDs), and circular waveguides with the same circumference as rectangular waveguides (denoted by WCCs). It is demonstrated that WCFs exhibit the highest values of maximum Ptrans together with lowest α and ploss due to their characteristics of microwave field configuration. Circular waveguides (e.g. WCF1150) made of Cu or Al with large dimensions operating at 0.915 GHz are suitable for microwave heating through long-distance microwave energy transport over the distance compared to traditional rectangular waveguides, with up to ∼50% reduction of power loss. Optimal waveguides for long-distance uses can be obtained by assessing microwave propagation characteristics together with manufacturing cost, depending on specific applications