Cat5e Shielded | RF Amplifiers | Cellular Repeate | Wireless Products

RF power amplifiers fall into different classes based on their peculiar endurance, linearity and distortion levels. Class E is one of the finest types of RF power amplifiers used to achieve greater efficiency. What sets them apart is that the transistor in Class E amplifier acts as a switch with ON/OFF function. To avoid recurring high voltage and current fluctuations, load network controls the voltage and current waveforms in such a manner that power dissipation is lowest at all the times especially in between switching transitions.

Another feature which differentiates Class E RF power amplifiers from Class B and C is that they can function with reduced power losses by an approx factor of 2.3. If class B and C amplifiers have drain efficiency of 65% the same would be 85% in case of Class E amplifiers. Both fixed tuned operations and narrowband operations for frequencies as wide as 1.8:1 can be performed using Class-E amplifiers. They can be even designed to work as they are without needing any “fiddling” or “tweaking”.

Efficiency for a Class E RF power amplifier lies in the amount of output power it gives without wasting much power. Below are the 6 principles that help the amplifier achieve its maximum productivity:

• When “On” transistor in the amplifier acts as a low resistance closed switch ensuring that the voltage remains close to Zero even when the current flowing is high.
• When “Off” transistor in the amplifier acts as open switch and keeps the current at zero even when the voltage is high.
• Voltage of the transistor will not rise until the current returns to zero
• Voltage of the transistor will become zero even before the current starts to increase
• Transistor voltage remains zero before the switch is turned “ON”
• Voltage slope of the transistor also remains zero at the time of turn “ON”

When all these principles are adhered to the RF power amplifier does not face situations of immediate increase in voltage and current and so are able to function as expected for a longer duration of time.