The signal amplified by the amplifier has a lot to do with the frequency of the signal. If the frequency is too high or too low, the operational amplifier will have a lot of distortion when amplifying the signal. Each operational amplifier can only amplify signals with a specific frequency width, such as from f1 to For signals between f2 frequencies, then the size of f2-f1 is the bandwidth of the op amp. The broadband power amplifier refers to an operational amplifier with a very wide bandwidth, that is, signals with small or large frequencies can be perfectly amplified.
The application of broadband power amplifiers has now begun to expand from military to civilian use, and is now in wireless communication, ITS communication technology, mobile phones, direct broadcast satellite reception (DBS), satellite communication networks, global positioning system (GPS) and millimeter wave automatic collision avoidance systems, etc. There are broad application
prospects in the field, and broadband also occupies a very important position in optical transmission systems.
In the fields of wireless communication, electronic warfare, electromagnetic compatibility testing and scientific research, there is great demand for radio frequency and microwave broadband amplifiers, and these fields have different requirements for broadband amplifiers, especially in the application of communication systems and electronic warfare systems , There are special requirements for broadband low noise and power amplifier performance indicators.
In the design, the port matching of the traditional narrowband amplifier is generally designed according to low noise or conjugate matching to obtain the low noise amplifier or the maximum output power. However, under broadband conditions, the input/output impedance changes are relatively large. At this time, it is inappropriate to use the concept of conjugate matching. Because of this, the matching circuit design method of broadband amplifiers is also different from narrowband amplifiers. The circuit structure of broadband amplifiers can be divided into the following types: feedback amplifiers; lossy matching amplifiers; distributed amplifiers; balanced amplifiers; Lington pair structure; active matching amplifier.
Each structure has its own characteristics and applicable conditions, and a reasonable choice should be made according to the performance index requirements of the specific amplifier during application.