Waveguide Slot Array Antenna for Near-field Heating of Underground Coal Seams

This paper proposes a waveguide slot array antenna operating at 2.45 GHz for near-field heating of underground coal seams. The main body of the antenna adopts a three-segment stepped circular waveguide. The radiator adopts a slot pair array, and the unit is an orthogonal slot pair, which increases the radiation aperture and benefits the radial uniform radiation of electromagnetic waves. The inner conductor of the coaxial line extends a certain distance into the waveguide, ensuring that the TM01 mode is excited. The inner conductor adopts two-section stepped copper wires to achieve better impedance matching. To cope with high temperature and high pressure, a silicon nitride ceramic sheath is used to wrap the antenna. The simulation results show good radiation performance, and this type of antenna has bright prospects in scenarios such as coalbed methane mining.