RF filter applications | Uses of RF Filter

This page describes applications or uses of the RF filters used in microwave industry. It covers most common RF filter applications or RF filter uses.

Filters are used in various domains such as electricals, electronics and communication. They are used in analog circuits as well as digital circuits. Analog filters are made of analog components and find place in analog circuits. Analog filters are of two types active and passive. Passive filter consists of inductors (L), capacitors (C) and resistors(R). Active filter consists of op-amplifiers in addition to L/C/R.

Digital filters are developed using programming languages such as matlab, c etc. and find place in digital components such as ASIC, processor or FPGAs. The programs of digital filters are flashed on ASIC/Processor/FPGA.

RF Filters are of analog type. They are constructed using microstrip or stripline or using any other type of transmission lines. These lines can be transformed into L, C and R basic components. Following section mentions core applications, functions and places where RF filters are employed.

RF filter

RF Filter applications or RF Filter uses

➤The figure depicts function of IF filters to allow IF (intermediate frequencies) of 1182.5 +/- 18 MHz to pass through using BPF (BandPass Filter) type. This will eliminate other nearby IF frequencies which may mix with LO frequency and will produce frequencies in the desired C band and lead to interference if present.
➤The figure depicts LPF used to pass lower IF frequencies in the range from 52 to 88 MHz.
➤The figure also depicts RF filter in the higher band from 5925 to 6425 MHz to pass frequencies only in C band. This will avoid nearby interference from other satellite bands.
➤It is used in broadcast receivers to select desired channel frequency and reject all the other frequency channels.
➤They are used in image frequency rejection in radio and TV receivers as well as satellite receivers.
➤Filters are also used multi-way loudspeakers. Here different audio frequencies are distributed to different loudspeakers used for high, bass and mid-range tones.
➤EMI filters are used for noise reduction.
➤They are also used to stop LO leakage in RF transceiver designs.

RF Filter Related Links

RF Filter calculator
Microstrip based RF Filter design
RF filter manufacturers
RF filter selection guide
RF filter terminologies


stripline basics and types
Microstrip line variants
Slotline basics and types
Finline basics
CPW(Coplanar Waveguide) basics
Types and basics of coaxial line
Types and basics of transmission line
RF Terms-Useful for RF design and testing.
RF-This page describes what is RF

RF and Wireless Terminologies