How to choose an RF Amplifier
An RF amplifier is an electronic device that is used to amplify a low power radio frequency signal to one with larger amplitude. Amplifiers are used in transmit and receive parts of a wireless system.
In the transmit chain they are used to amplify signals before they are sent out through the antenna and in the receive chain they are used to amplify weak signals that are captured by the antenna with minimal distortion. RF amplifiers have a wide range of applications in the wireless sector – military, test and measurement, mobile devices and wireless infrastructure.
The key specifications to look for in an RF Amplifier are:
Type: There are many types of rf and microwave amplifiers:
RF Power Amplifiers: Power Amplifiers convert low power high frequency signals to high power signals. This is usually used in the transmit chain to amplify the signal before it is sent out via an antenna.
Low Noise Amplifiers: RF Low noise amplifiers are used amplify a high frequency signal while maintaining a good signal to noise ratio. Low noise amplifiers are used at the beginning of the receive chain to amplify a signal with minimal degradation.
Other Amplifiers: There are a number of other amplifiers like gain blocks, differential amplifiers, driver amplifiers, limiting amplifiers etc.
Frequency (MHz): RF amplifiers are usually designed to work at a particular frequency range. The unit for frequency is Hz (Hertz).
Gain (dB): The gain of an rf amplifiers is the ratio of output to input power or amplitude – It is the measure of amplification of the rf amplifier.
Noise Figure (dB): Noise is an undesired signal that is generated up to some level in all electronics components and devices. Noise figure is the metric for noise performance is a circuit or system. The lower the noise figure, the higher the signal to noise ratio of a system.
Power Compression (dBm or W): Power Compression or P1dB is the point at which the input signal is amplified by an amount, which is 1 dB below the small signal gain of the device. It is the point beyond which the gain of the device no longer increases linearly as the input power is raised.
Package Type: RF amplifiers are available in a number of package types such as surface mount, raw die’s and connectorized.