Exploring the Pros and Cons of Guided Wave Radar Level Measurement

Guided wave radar, also known as time domain reflectometry or low-power pulse radar, like Emerson’s 5301 series, is installed atop tanks or bypass pipes. The waveguide probe typically extends throughout the depth of the container. Low-energy microwave pulses are sent down the waveguide at the speed of light. At the point where the waveguide meets the level (air/liquid interface), a significant proportion of the microwave energy is reflected back to the transmitter.

Limitations: Although it can be used in many operating conditions, attention should still be paid to the selection of the waveguide. There are several types of waveguides to choose from, and the choice depends on the application, length, and installation restrictions. Contact with metal objects will affect the signal, so the waveguide should not directly touch metal objects unless a coaxial waveguide is used. In applications where viscosity or adhesion changes easily, only a single waveguide can be used.