Multiphase flowmeter aperture antenna transmission and pressure retention

An aperture antenna assembly of a multiphase flowmeter to measure properties of a fluid in a vessel, the aperture antenna assembly comprising:

• at least one radiating element configured to transmit or receive an electromagnetic signal along at least one measurement plane orthogonal to a direction of flow of the fluid in the vessel;
• a pressure retaining member configured to prevent the fluid from entering the aperture antenna assembly through a measurement window of the aperture antenna assembly, wherein at least a portion of the pressure retaining member separates the at least one radiating element and the fluid;
• a metal housing, the pressure retaining member being at least partially within the metal housing, the at least one radiating element being coupled to the metal housing;
• and
• at least one electrical conductor shim disposed between the metal housing and the vessel or at least partially between the pressure retaining member and the vessel.

A multiphase flowmeter configured to measure properties of a fluid in a vessel, comprising:

• a first aperture antenna assembly;
• and
• a second aperture antenna assembly, wherein the first aperture antenna assembly is coupled to a first side of the vessel and the second aperture antenna assembly is coupled to a second side of the vessel, and wherein the first the first aperture antenna assembly and the second aperture antenna assembly each comprise:
• a metal housing;
• a pressure retaining member configured to prevent the fluid from entering the respective aperture antenna assembly through a measurement window of the aperture antenna assembly;
• and
• at least one radiating element coupled to the metal housing, wherein:
• at least a portion of the pressure retaining member is configured to separate the at least one radiating element and the fluid, wherein the at least one radiating element is configured to transmit or receive an electromagnetic signal along at least one measurement plane orthogonal to a direction of flow of the fluid in the vessel;
• the at least one radiating element of the first aperture antenna assembly is configured to transmit an electromagnetic signal through the fluid and is configured to receive at least a portion of the electromagnetic signal reflected by the fluid in the vessel;
• the at least one radiating element of the second antenna aperture assembly is configured to receive the electromagnetic signal;
• and
• the at least one radiating element of the second aperture antenna assembly is oriented at one or more angular displacements with respect to the at least one radiating element of the first aperture antenna assembly.