US Patent 7610816 Flow measurement device

The present invention discloses a flow measurement device that includes: a wave guide tube type resonant cavity; a penetrating space that penetrates the resonant cavity; a duct support part that is made of a dielectric substance and is in the resonant cavity and surrounds an outside of the penetrating space; a transmitting antenna that transmits a microwave in a direction along a longitudinal axial direction of the resonant cavity to provide a standing wave or a traveling wave of the microwave, with the microwave transmitted in a space that is outside of duct support part and inside of the resonant cavity; and a receiving antenna that receives the standing wave or the traveling wave.