Advantages of RF Filter | disadvantages of RF Filter

This page covers advantages and disadvantages of RF Filter. It mentions RF Filter advantages or benefits and RF Filter disadvantages or drawbacks. It also describes RF Filter basics.

What is RF Filter?

The filters which operates on radio frequencies (20 KHz to 300 GHz) are known as RF filters. There are different types of RF filters based on which part of frequency bands are allowed or blocked through them.

Hence the common filter types are as follows. The figure-1 depicts the responses of these filter types.
• LPF (Low Pass Filter): It passes all the lower frequencies of RF signal upto desired cutoff frequency and blocks the higher ones.
• HPF (High Pass Filter): It passes all the higher frequencies of RF signal from defined cutoff frequency and blocks the lower ones.
• BPF (Band Pass Filter): It passes signals within specific frequency bands with little or no attenuation and blocks frequencies on both the sides of this band.
• BSF (Band Stop Filter): It blocks frequencies in a specific band and passes all the other frequencies.

RF Filters are of analog type. They are constructed using microstrip or stripline or using any other type of transmission lines. The different filter types have their respective advantages and disadvantages.

Benefits or advantages of RF Filter

Following are the benefits or advantages of RF Filter:
➨They are used in wide variety of applications such as in broadcast receivers to select desired channel frequencies, in radio receivers to reject the image frequencies, as EMI filters to reduce noise levels, in transceiver to reduce LO leakage level etc.
➨It is easy to integrate with rest of the system without any issues as the connectorised and connectorless modules can be easily constructed.
➨Troubleshooting is easy due to easy accessibility over the entire structure.
➨It is smaller in size except the waveguide based RF filters.

Drawbacks or disadvantages of RF Filter

Following are the disadvantages of RF Filter:
➨It passes all the frequencies with more or less attenuations. Hence appropriate RF filter is choosen to attenuate undesired frequencies as per level needed in order to make the system function as per specification (Eb/No or BER).
➨It is complex to implement which depends on filter types and specifications to be achieved.
➨It requires expensive software to perform simulation.
➨It requires manual tuning to achieve desired return loss at the input/output ports. This is time consuming process.