RF Limiters Basics & Selection
RF Limiters are used to protect components from stray signals by limiting their amplitude to a level that they can handle. These are usually used in the receive chain to protect against high power incoming signals. Components in the receive chain like an LNA (low noise amplifier) are small, highly sensitive devices that usually handle low power levels from the antenna, limiters are used to protect such devices from a sudden surge in input power.
Selecting RF Limiters
When selecting a RF limiter it is important to know the parameters that you need to specify. Below are a list of the key parameters to look out for when selecting a limiter:
Input Power (dBm) or Threshold Level: This is the maximum input power that the limiter will allow. Any power above this level will be limited.
Flat Leakage (dB): This is the power that leaks through when the device is under high input power conditions.
Spike Leakage (dB): This is the power that leaks through when a high power pulse is applied to the limiter.
Type: Most limiters can be designed using Pin Diodes or Schottky diodes. These can also be designed using a MMIC process.