Guided Wave Radar
In a guided wave radar level measurement system, the waveguide is a probe immersed in the liquid (or dry, bulk media). The-high frequency electromagnetic pulses transmitted down the probe are reflected at the point of discontinuity between the air and the process medium. As with other "time of flight" instruments, those reflections are measured by high-speed circuitry in the transmitter, thus establishing the level measurement. The dielectric constant for typical process media can range from 1.4–100. The higher the dielectric constant of the medium being measured, the stronger the reflected signal is. A coaxial outer layer can be included as well as a rope version.