Guided Wave Radar Versus Through-air Radar Level Sensors

[vignesh]

To overcome the measurement problems faced by through-air radar systems, guided wave radar systems are generally employed since they offer following advantages over through-air radar systems:

1. “As with through-air radar, a change from a lower to a higher εr causes the reflection. Guided wave radar is 20 × more efficient than through-air radar because the guide provides a more focused energy path.”

2. In GWR method, various antenna designs and configurations make it possible to determine level of fluids having dielectric constant less than 1.4.

3. Also, these systems can be mounted in both vertical and horizontal positions depending upon the application.

4. These systems offer and efficient and clear path for signal travel.

5. The performance of GWR systems is not disturbed by vapors, foams, high temperature or pressure conditions.

6. These systems can operate in vacuum too without requiring any recalibration.

7. Beam divergence issues and false echoes resulting from tank walls and obstructions are not present in these guided wave radar systems.

[vignesh]

Problems of Through-air Radar Level Sensors

Through-air Radar Level Sensor Problems

Non-invasive systems of measurement are basically known as the through-air radar systems. They usually employ a horn antenna or a rod antenna for sending microwave beams onto the surface of the liquid being measured. These antennas mounted at the top of the tank then receive the reflected microwave signal back from the fluid surface. A timing circuit is incorporated in the systems which measures the time of flight and hence the distance between the antenna and the fluid level is determined. The…