Abstract: A microwave printing device comprising an inlet for a filament 1 of an electrically conductive material, an outlet for the filament and a microwave heating device 4 for heating the filament 1 by means of microwave radiation. The microwave heating device 4 comprises at least one coaxial resonator. The coaxial resonator is formed by an outer conductor, which forms a cavity 11, and a coaxial inner conductor. The coaxial resonator also comprises a microwave radiation input for coupling in microwave radiation. The filament 1 preferably forms the inner conductor or part of the inner conductor of the resonator. A system for the additive manufacture of moulds, comprising the microwave printing device, and a process for the additive manufacture of moulds with the aid of the microwave printing device.

Abstract: In a continuous flow microwave heater for heating a fluid including a microwave source connected to an applicator so as to supply microwave energy to the applicator, the applicator is a rectangular block-like resonator space with opposite front walls and side walls with a microwave in-coupling opening in one of the side walls through which the microwave energy is supplied to the resonator space in which a linearly polarized base mode TE10 is excited. A dielectric tube extends through the resonator space to conduct the fluid to be heated through the applicator, the dielectric tube being so arranged that the microwave energy supplied to the applicator is completely dis-sipated into the fluid flowing through the dielectric tube.

Abstract: In a continuous flow microwave heater for heating a fluid including a microwave source connected to an applicator so as to supply microwave energy to the applicator, the applicator is a rectangular block-like resonator space with opposite front walls and side walls with a microwave in-coupling opening in one of the side walls through which the microwave energy is supplied to the resonator space in which a linearly polarized base mode TE10 is excited. A dielectric tube extends through the resonator space to conduct the fluid to be heated through the applicator, the dielectric tube being so arranged that the microwave energy supplied to the applicator is completely dissipated into the fluid flowing through the dielectric tube.

Abstract: In a microwave system for heating, and controlling the temperature of, a heat bath including a containment for a liquid, with a wall on which the microwave system is mounted, the microwave system comprises a microwave source operating at an ISM frequency of 2 to 5 GHz, a microwave conductor for conducting microwaves from the microwave source to a resonator through a ceramic window disposed in the resonator wall, the resonator has a common wall portion with the containment, which common wall portion consists of a grid having a mesh width that prevents passage of microwave radiation but provides for communication of the liquid between the resonator and the containment.

Abstract: In a high-mode microwave resonator for high-temperature treatment of materials, the resonator comprises a housing with a polygonal cross-section formed by planar housing wall segments and planar end walls. One of the end walls includes an in-coupling window arranged so as to direct a microwave beam into the resonator at an angle with respect to the housing axis and toward an edge between adjacent wall segments such that the microwave beam is divided, upon reflection, into two symmetrical beam components which, upon further reflection, provide for an essentially homogeneous field distribution throughout the resonator interior.