Intrinsically safe radio frequency (rf) adapter

A radar-based level sensing system (sensing system), comprising:

• a radar level gauge (RLG);
• a tank antenna within a tank coupled to said RLG by an intrinsic safety (IS) radio frequency (RF) adapter combination, said IS RF adapter combination including:
• a multi-layer printed circuit board (PCB) comprising a dielectric substrate material having a 25° C. loss tangent of <0.010 at 10 GHz including a first layer on a first side and a second layer on a second side;
• said first layer including an IS circuit including a signal trace having at least one series capacitor that has a 25° C. capacitance less than or equal to (≦) 50 Pico Farads (pF) coupled between a core of a tank-side coaxial connector and a core of a RLG-side coaxial connector, wherein a shield of said RLG-side coaxial connector is coupled to a first ground plane;
• said second layer including a second ground plane coupled to a shield of said tank-side coaxial connector, and
• wherein said first ground plane at least partially overlaps said second ground plane;
• a coaxial cable having a first end coupled to said tank-side coaxial connector and a second end opposite said first end;
• a coaxial feed-through coupled to said coaxial cable, and
• a metal enclosure having including a tank-side aperture, wherein said coaxial feed-through is partially within said metal enclosure, and wherein said RLG, said IS RF adapter combination and said coaxial cable are all sealed within said metal enclosure.

A method of level sensing, comprising:

• providing a radar-based level sensing system (sensing system) including a radar level gauge (RLG) directly coupled by a direct coupling connection to a tank antenna within a tank having a material therein by an intrinsic safety (IS) radio frequency (RF) adapter combination,
• transmitting a radar signal generated by said RLG over said direct coupling connection to said tank antenna;
• responsive to said radar signal interacting with said material, receiving a reflected echo signal over said direct coupling connection at said RLG, and
• determining a level of said material in said tank from said echo signal.