How Do RF Cavity Filters Work? Keenlion Explains with New 471-481MHz Design

An RF Cavity Filter works by storing energy in a resonant metallic cavity and releasing only the desired frequency while reflecting the rest. In Keenlion’s new 471-481 MHz Cavity Filter, a precisely machined aluminum chamber acts as a high-Q resonator, permitting signals inside the 10 MHz window and rejecting everything else with >40 dB isolation.
Inside the471-481 MHz Cavity Filter

Inside the 471-481 MHz Cavity Filter

The cavity length is cut to half-wavelength at 476 MHz, creating standing waves. A capacitive probe inserted at the electric-field maximum couples energy in and out, while a tuning screw varies the effective volume, shifting the center of the Cavity Filter without adding loss, ensuring the Cavity Filter maintains insertion loss ≤1.0 dB and Q ≥4 000.

Technical Advantages of Keenlion’s Design

Frequency Precision: Tailored for 471-481MHz with ±0.5MHz tolerance.

Low Insertion Loss: <1.0 dB ensures minimal signal degradation.

High Power Handling: Supports up to 20W continuous power.

Environmental Resilience: Operates reliably from -40°C to 85°C (MIL-STD tested).

Manufacturing Excellence

Keenlion’sCavity Filteris produced in their ISO 9001-certified facility, combining 20 years of RF expertise with automated testing. Each unit undergoes 100% VNA verification to guarantee performance. The company offers rapid customization for frequency bands, connectors, and mounting options, with samples shipped in 15 days.

Applications

This Cavity Filter is ideal for:

Public Safety Radio Systems

Industrial IoT Networks

Critical Infrastructure Communications
Its high selectivity prevents interference in dense RF environments.

Choose Keenlion

Keenlion delivers factory-direct Cavity Filters with proven reliability, competitive pricing, and lifetime technical support. Their vertical manufacturing control ensures swift prototyping and volume production.