A Complete Guide: Selection Guide, Working Principles & Application Differences Between Guided Wave Radar and Non-contact Radar Level Transmitters

1. Working Principles

1.1 Non-contact Radar Level Transmitter (FMCW / Pulse Radar)

• Non-contact measurement without touching the process medium
• Signals radiate in space with natural divergence and attenuation
• Echo intensity depends on the dielectric constant of the measured medium

1.2 Guided Wave Radar Level Transmitter (GWR)

• Contact-type measurement equipped with probe rod or cable
• Signals transmit along conductors with negligible attenuation, free from interference of vapor and foam
• Capable of simultaneous liquid level and interface measurement

2. Fundamental Principle Differences

• Signal Propagation Mode

   

  Non-contact Radar: Spatial radiation transmission through air

   

  Guided Wave Radar: Directional conduction along metal waveguide probes
   
• Signal Performance

   

  Non-contact Radar: Prone to divergence and signal attenuation

   

  Guided Wave Radar: Concentrated, stable signal with low attenuation
   
• Measuring Capacity

   

  Non-contact Radar: Only for liquid level measurement

   

  Guided Wave Radar: Support liquid level and liquid-liquid interface dual measurement
   
• Anti-interference Mechanism

   

  Non-contact Radar: Relies on optimized algorithms and antenna design

   

  Guided Wave Radar: Inherently superior anti-interference via physical signal confinement
   

3. Selection Guidelines

3.1 Preferred Application Scenarios for Guided Wave Radar (GWR)

• Sites requiring liquid-liquid interface measurement such as oil-water separation interface
• Low dielectric constant media: gasoline, diesel oil, LNG, LPG and light hydrocarbons
• Working conditions with heavy foam, vapor and dust
• Measuring range within 30 meters
• High-temperature and high-pressure sealed vessels
• Applications demanding high precision and excellent stability
• Calm storage tanks without agitation or internal structural interference

3.2 Preferred Application Scenarios for Non-contact Radar

• Viscous media, slurry, asphalt and sludge
• Strong corrosive media such as sulfuric acid, hydrochloric acid and strong alkali
• Vessels with complex internal structures including agitators, coils and baffles
• Long measuring range over 30 meters, maximum up to 70 meters and above
• Sanitary and anti-corrosion occasions where medium contact is prohibited
• Media prone to crystallization and adhesion

4. Comparative Table