A power amplifier is an electronic amplifier designed to increase the magnitude of the power of a given input signal. It is used to increase power of input signal to operate speaker, headphone and RF transmitter electrical level of output load. Different from Current and Voltage Amplifiers, the Power Amplifier are designed to directly drive a load and serve as the final block in the amplification chain.
The input signal has to above certain range of a power amplifier. Thus, pre-amplified from current or voltage amplifier input to power amplifier after modification instead of passing the original audio or RF signal to the power amplifier.
There are three types of Power Amplifier based on different output devices:
Audio Power Amplifier
RF Power Amplifier
DC Current Amplifier
RF Power Amplifier
Wireless transmission requires modulated waves to be sent over long distances through the air. The signal is transmitted by using an antenna, and the transmission range depends on the power of the signal fed to the antenna.
For wireless transmissions such as FM radio, antennas require signals with input powers of thousands of kilowatts. Thus, the RF Power Amplifier is used to increase the power amplitude of the modulated wave to a level sufficient to achieve the desired transmission distance.
The microwave and millimeter wave High-Power Amplifiers that are often heard are high-end testing instruments, and have been widely used in Electro-Magnetic Compatibility (EMC) Testing, 5G Communication Testing, Electronic Warfare Jamming & Countermeasures, Specific Electromagnetic Environment Simulation, Aerospace and many other fields.
As a Radio Frequency Microwave Power Amplifier, it has gone through the era of electron tubes and traveling wave tubes (TWT), and now it has entered the era of so-called Solid-State Amplifiers that use semiconductors as the core. High-power Solid-State Power Amplifiers is now domaining in the lower frequency bands.
Solid State Power Amplifier Introduction
Solid-state power amplifiers have the advantages of small size, low operating voltage, long life, high efficiency, and high reliability. They have been widely used in radio frequency/microwave/millimeter wave systems such as radar, mobile communication, jamming and identification, and occupy a very important position.
To put it simply, a solid-state power amplifier is a module that integrates and packages circuits with amplification functions to amplify signals.
There are many kinds of solid-state power amplifiers, such as Audio Solid-State Power Amplifiers and Microwave Signal Solid-State Power Amplifiers. They are characterized by being easy to use, only need to provide working power to the module, input signals that meet the requirements, and connect well the output, and then they can work normally.