Stacked-transistor power amplifiers for high-power radio frequency and millimeter-wave wireless applications

This technology is an integrated circuit design for a stacked-transistor power amplifier (PA) that delivers the high output power required of wireless transmitters while maintaining ideal Class-E efficiency.

Unmet Need: Efficient high-power amplification for radio frequency and millimeter-wave transmitters

High-power amplification is a critical functionality for radio frequency (RF) and millimeter-wave transmitters. However, battery life is a key limitation in wireless systems such as cellular phones, Wi-Fi networks, and Bluetooth devices. Class-E switching PAs can achieve ideal 100%-efficient operation and are, therefore, highly useful in energy-sensitive applications. However, these amplifiers are typically limited in their output power capabilities due to the breakdown voltages associated with a given device technology. Cascaded designs can overcome this limitation and achieve high output powers, but existing stacked-transistor architectures do not realize the ideal Class-E behavior necessary for maximizing energy efficiency. As such, there is a need for a PA that can achieve high output powers with Class-E behavior for energy-efficient amplification.

The Technology: Stacked-transistor amplifier maintains Class-E switching, enabling high-efficiency power amplification

This technology is a stacked-transistor power amplifier that places a Class-E load network at the drain node of each stacked device to impart a true Class-E behavior to all devices in the stack. Unlike existing staked devices that are only partially successful in achieving Class-E behavior, this technology maintains Class-E-like behavior for all transistors in the stack. As a result, this technology enables high-power switching PAs for RF and millimeter-wave applications to be realized with standard CMOS processes, obviating the need for implementation of separate devices.

Two operational prototypes implemented in 45nm IBM Silicon-on-Insulator (SOI) technology have been successfully demonstrated at 45 GHz.

Applications:

  • Energy-constrained RF and millimeter-wave transmitters for wireless devices, including cellular phones, wireless LAN, millimeter-wave vehicular radar, and 60 GHz wireless personal area networks (WPANs)
  • High-efficiency, high-power PAs in CMOS technology enabling monolithic integration of the PA with the rest of the transmitter
  • Improved efficiencies and output power for III-V PAs

Advantages:

  • Achieves high output powers with ideal Class E behavior and efficiency
  • Enables high-efficiency, high-power PAs in both CMOS and III-V materials
  • Ideal class E behavior and efficiencies
  • Improved efficiencies and output power for III-V PAs

Lead Inventor:

Harish Krishnaswamy, Ph.D.

Patent Information:

Patent Issued

Related Publications:

Tech Ventures Reference:

Quick Facts:
Tags
45 nm processAmplifierBluetoothCMOSElectric batteryExtremely high frequencyHertzIntegrated circuitProtocol stackRadarRadio frequencyWireless LAN
Inventors
Anandaroop ChakrabartHarish Krishnaswamy
Manager
Greg Maskel
Departments
Electrical Engineering
Divisions
Fu Foundation School of Engineering and Applied Science (SEAS)
Reference Number
M11-082
Release Date
2015-06-12