It is desirable to obtain high RF power amplifier efficiency in many practical applications. At least one, if not all, of the following requirements is important: low power consumption (especially for battery-operated equipment), low temperature rise of the components, high reliability, small size, and light weight. Although the parasitic energy losses in, for example, inductors and capacitors are sometimes important, the major power loss in power amplifiers is usually due to power dissipated in the transistor(s). This was true for the Class A, B, and C PAs (their theoretical collector efficiency was calculated in Sections 2.1 through 2.3).

Chapter Contents:

• 4.1 Idealized Operation of the Class E Amplifier
• 4.2 Practical Considerations
• 4.3 Amplitude Modulation of the Class E Amplifier
• 4.4 Amplifiers with Finite DC Feed Inductance
• 4.5 Other Class E Configurations
• 4.6 Class E Frequency Multiplier
• 4.7 CAD of the Class E Amplifier
• 4.8 Class E Versus Class B, C, and D Amplifier
• 4.9 A Condition Required to Obtain η = 1 and P0 ≠ 0
• 4.10 Notes
• 4.11 References

Inspec keywords: circuit reliability; capacitors; transistors; radiofrequency amplifiers; power consumption; power amplifiers; inductors

Other keywords: class E power amplifier; battery-operated equipment; RF power amplifier efficiency; power consumption; reliability; parasitic energy loss; inductor; transistor; collector efficiency; temperature rise; capacitor; power dissipation

Subjects: Inductors and transformers; Reliability; Capacitors; Amplifiers