Envelope Tracking Power Amplifier RF Bandwidth Extension
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Solution Overview
Problem
Radio frequency (RF) power amplifiers with fixed voltage supplies are inefficient at lower power levels due to high peak-to-average power ratio waveforms, leading to significant heat dissipation and reduced energy efficiency, particularly in broadband communications where existing envelope tracking power supplies are limited by RF bandwidth.
Innovation Solution
The implementation of an envelope tracking power supply with a transmission line switch that alters the electrical length of the quarter-wavelength line between the power supply and the RF power amplifier, using PIN or MEMS switches to extend the RF bandwidth by adding bypasses at different locations, allowing efficient operation across a broader frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking power supply is used to improve energy efficiency, then energy efficiency is improved, but RF bandwidth is limited
Solution Approach 1:
The patent applies dynamics by making the transmission line electrical length adjustable through switching between different configurations. The system dynamically reconfigures the transmission line between a first electrical length for first RF bandwidth and a second electrical length for second RF bandwidth, allowing the envelope tracking power supply to adapt to different bandwidth requirements while maintaining energy efficiency across both bandwidth ranges
Solution Approach 2:
The patent changes the electrical length parameter of the transmission line to extend RF bandwidth. By switching between different electrical lengths (first and second electrical lengths), the system expands the operational RF bandwidth beyond what a fixed electrical length configuration could achieve, while preserving the energy efficiency benefits of envelope tracking
2Device complexity
If fixed DC voltage supply is used, then device simplicity is maintained, but energy efficiency deteriorates at lower power levels
Solution Approach 1:
The patent replaces the static fixed DC voltage supply with a dynamic envelope tracking power supply that adjusts the voltage envelope to match the RF signal characteristics. This dynamic adjustment allows the system to maintain high energy efficiency across varying power levels while keeping the overall device architecture relatively simple through the use of standard envelope tracking components
Data Source
AI summary
An envelope tracking power supply (ET PS) transmission line switch can be operable between an ET PS and a radio frequency (RF) power amplifier (PA). The ET PS transmission line switch assembly can include a quarter wavelength (¼λ) transmission line configured for high impedance at a specified low RF and a switch coupled to a specified point on the quarter wavelength transmission line to generate a high frequency quarter wavelength transmission line when the switch is toggled. The quarter wavelength transmission line is configured to be coupled to a voltage output of the ET PS and a RF output of the RF PA. The high frequency quarter wavelength transmission line is configured for high impedance at a specified high RF, and the specified high RF is higher than the specified low RF.