A bandpass filter is a filter that selects a specific frequency range to pass a signal unattenuated. It can be typically made from all common transmission line median varying from waveguide to microstrip line. Filter circuits are made by combining the properties of low-pass and high-pass into a single filter and such filter called a band-pass filter. It works to screen out frequencies that are too low or too high, so as to provide passage only to frequencies within a certain range. In certain applications, there is a need to filter a particular band or spread, or frequencies from a wider range of mixed signals.
There are many different types of bandpass filters available in the market. Some of these filters can be done with external power as well as active components such as integrated circuits, transistors. These filters are also called active bandpass filters. On the other hand, there are some other kinds of bandpass filters that use external power sources as well as passive components like capacitors and inductors, which are named passive Bandpass filters. These filters are extensively applicable in wireless transmitters as well as receivers. These filters are also widely used in optics such as LIDARS, lasers, sonar, instruments, medical, and Seismology applications.
