Shared-Substrate Doherty Transceiver for TDD Harmonic Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Doherty amplifiers used in transceiver circuits for wireless communication face challenges in maintaining high efficiency over a wide output power range and suffer from adjacent channel leakage due to high-order harmonic distortion, which affects reception sensitivity, especially when using a common antenna for transmission and reception.
Innovation Solution
Implementing a transceiver circuit with a Doherty amplifier and a low noise amplifier on a shared package substrate, utilizing a time division duplexing (TDD) scheme to switch between transmission and reception states, thereby isolating high-order harmonic distortion and preventing its impact on reception sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a Doherty amplifier is used to achieve high efficiency over a wide output power range, then efficiency is improved, but high-order harmonic distortion increases causing adjacent channel leakage
Solution Approach 1:
The patent segments the amplification function into two separate amplifiers: a Doherty amplifier for transmission signal amplification and a low noise amplifier for reception signal amplification. This segmentation allows each amplifier to be optimized for its specific function, enabling the Doherty amplifier to operate at high efficiency without its harmonic distortion affecting reception, since the reception path uses a separate low noise amplifier.
Solution Approach 2:
The patent extracts the reception amplification function from the transmission amplification path. By using a separate low noise amplifier dedicated to reception signal amplification, the harmful high-order harmonic distortion generated by the Doherty amplifier is prevented from entering the reception signal path, thus solving the adjacent channel leakage problem while maintaining transmission efficiency.
2Device complexity
If a common antenna is used for both transmission and reception, then device complexity is reduced, but reception sensitivity deteriorates due to adjacent channel leakage
Solution Approach 1:
The patent segments the signal processing path into separate transmission and reception amplification paths, each with dedicated amplifiers. This allows a common antenna to be used while preventing transmission harmonic distortion from degrading reception sensitivity, as the reception path uses a separate low noise amplifier that does not introduce the same distortion problems.
3Manufacturing precision
If digital pre-distortion is applied to cancel distortion, then linearity is improved, but bandwidth is limited reducing effectiveness for wideband signals
Solution Approach 1:
The patent accepts the presence of harmonic distortion in the transmission path and uses a separate low noise amplifier for reception that is not affected by this distortion. This approach avoids the complexity and bandwidth limitations of digital pre-distortion systems while effectively solving the linearity problem through physical separation of transmission and reception paths.
Data Source
AI summary
A Doherty amplifier including a main amplifier and a peak amplifier is mounted on a package substrate. A low noise amplifier is further mounted on the package substrate. A transmit/receive switch switches in terms of time between a transmission connection state in which an output signal of the Doherty amplifier is supplied to an antenna and a reception connection state in which a signal received by the antenna is inputted to the low noise amplifier.