(486) Filter Design Part 1. Different Types of Microwave Filter: Lowpass, Highpass, Bandpass & Bandstop.

Low Pass Filter

A filter that allows low frequency signals to pass while attenuating (stopping) high frequency signals.

High Pass Filter

A filter that allows high frequency signals to pass while attenuating (stopping) low frequency signals.

Band Pass Filter

A filter that allows signals within a certain range of frequencies to pass while attenuating signals outside that range.

Band Stop Filter

A filter that attenuates signals within a certain range of frequencies while allowing signals outside that range to pass.

Cut-off Frequency

The frequency at which the output signal power drops to a specified level (often half the maximum power) for a filter.

Pass Band

The range of frequencies that are allowed to pass through a filter.

Stop Band

The range of frequencies that are attenuated by a filter.

Center Frequency

The frequency in the middle of the pass band for a band pass filter.

Notch Filter

Another name for a band stop filter; it specifically rejects a narrow band of frequencies.

Ideal Filter

A theoretical filter that instantly separates frequencies with no transition between pass band and stop band.

Non-Ideal Filter

A filter that takes time to respond from the pass band to the stop band, showing a gradual transition.