High Efficiency Pulse Modulated Power Amplifiers

Summary

UCLA Researchers in the Electrical Engineering Department have developed a novel amplifier for efficient amplification of RF signals in non-constant envelope modulation, without compromising the fidelity of the modulation information.

Background

The power efficiency of conventional linear power amplifiers can degrade severely when driven by non-constant envelope signals. Doherty amplifiers, outphasing, Kahn techniques, and delta-sigma modulation can provide improved efficiency, but at the cost of limited linearity performance and operating bandwidth, or other implementation difficulties.

Innovation

The novel amplifier provides maximum efficiency for a wide range of output power levels, without compromising linearity performance. Control is simple and linearity is robust. The amplifier is easy to implement without requiring any specialized high speed devices.

Applications

• RF transmitters
• Wireless base stations
• Power amplification in wireless or wired RF systems
• Non-constant envelope modulation

Advantages

• Maintains maximum efficiency and linearity performance over a wide range of output power fluctuations
• Avoids the middle-range efficiency dip associated with traditional Doherty amplifiers
• Provides robust linearity performance
• Simplifies bias control conditions, gain characteristics, and peripheral sizes of the devices to achieve linear amplification
• Suitable for an envelope delta-sigma modulation (EDSM) approach
• Addresses the efficiency problems associated with non-constant envelope modulations

State of Development

The device has been validated in simulations, fabricated, and successfully tested in experiments

Patent Status