RF Limiter Selection Guide: Benefits and Manufacturers

Introduction:

RF limiters are crucial for safeguarding sensitive components from excessive power levels. Selecting the correct RF limiter is essential for ensuring circuit safety and maintaining consistent system performance.

What is an RF Limiter?

An RF limiter is a device designed to restrict an RF signal to a specific power limit, as determined by its manufacturer. It serves to protect receivers and other RF components from damage caused by high power. Furthermore, it’s utilized to mitigate amplitude fluctuations and maintain the desired power level. Typically constructed using PIN diodes or PIN Schottky diodes, microwave or RF limiters are available for frequencies ranging from 500 MHz to 18 GHz.

Figure 1 illustrates an application of an RF limiter in an FM demodulator system.

Selection Guide

When selecting an RF limiter, consider the following key parameters:

• Frequency Range: Verify that the limiter supports your required operating frequency.
• Power Handling Capacity: Ensure the limiter can withstand the maximum input power level without being damaged (e.g., +30 dBm).
• Insertion Loss: A lower insertion loss (ideally less than 1 dB) is desirable to minimize signal degradation during normal operation.
• Limiting Threshold: This defines the power level at which the limiter begins attenuation (e.g., +10 dBm to +20 dBm).
• Recovery Time: A faster recovery time (in the nanosecond range) is critical for protecting sensitive components in high-speed RF circuits.
• Impedance Matching: Typically 50 Ohms.
• Response Time: A fast-acting limiter protects circuits from sudden power surges in real-time.
• Form Factor & Integration: Available in SMT, coaxial, and waveguide designs.
• Operating Temperature: Ensure the operating temperature of the limiter is within acceptable range of the application.

Advantages of RF Limiters

RF limiters offer several key advantages:

1. Protection of Low Power Circuits: Prevents damage to components such as receivers, mixers, and detectors from high-power RF signals.
2. Signal Integrity: Ensures signal integrity by limiting excessive power and reducing distortion in communication systems.
3. Improved Durability: Reduces wear and tear on RF front-end components, thereby enhancing overall system durability.
4. Wide Input Power Range: Allows receivers to handle a wide range of input power levels without saturation.
5. Reliable Performance: Offers reliable performance even in harsh environmental conditions.

RF Limiter Manufacturers

The following table lists some of the leading manufacturers and vendors of RF limiters:

Conclusion

Investing in a high-quality RF limiter is essential for preventing damage and improving overall system reliability. Exploring offerings from leading manufacturers is crucial for finding the best solution for your specific needs.