Switching Power Amplifier Paths to Reduce Harmonic Leakage
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Solution Overview
Problem
Wireless devices supporting multiple cellular protocols and frequency bands face challenges in reducing harmonic leakage, which degrades reception quality and increases costs and size due to the need for separate amplification paths and careful circuit design.
Innovation Solution
Incorporating a switch and controller within the power amplification system to selectively enable or disable power amplifiers based on band select signals, routing unintended harmonic signals to ground to prevent leakage, thereby improving reception quality without the need for separate amplification paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate amplification paths are used for different cellular protocols, then reception quality is maintained, but device size and cost increase
Solution Approach 1:
The patent merges multiple amplification paths into a single shared power amplifier by introducing a switching mechanism. The switch selectively connects the antenna to different protocol-specific RF circuits, allowing one power amplifier to serve multiple cellular protocols (CDMA, WCDMA, GSM) without requiring separate amplification paths for each protocol, thereby reducing device size while maintaining reception quality.
Solution Approach 2:
The patent introduces dynamic switching capability to statically designed RF circuits. The switch dynamically reconfigures the connection between the antenna and RF circuits based on the active protocol, enabling a single power amplifier to adaptively serve different protocols with different frequency bands and signal characteristics, thus eliminating the need for multiple fixed amplification paths.
2Reliability
If separate amplification paths are used for different cellular protocols, then protocol-specific performance is optimized, but device cost increases
Solution Approach 1:
The patent combines multiple protocol-specific RF circuits around a single shared power amplifier. The switching mechanism routes signals from different protocols (CDMA, WCDMA, GSM) to the same power amplifier, reducing the total component count and bill of materials cost while maintaining protocol-specific performance through selective circuit activation.
Solution Approach 2:
The power amplifier is designed with universal functionality to handle multiple cellular protocols. By making the power amplifier protocol-agnostic and using switching to present the appropriate input signal, the system achieves multi-functionality without requiring separate amplifiers for each protocol, thereby reducing device cost.
3Reliability
If filtering components are added to reduce harmonic leakage, then reception quality improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-selecting the appropriate RF circuit and frequency band before signal amplification. The switching mechanism ensures that only the relevant protocol-specific circuit is active at any given time, which naturally filters out unwanted harmonics and interference from other protocols without requiring additional filtering components, thus improving reception quality while maintaining circuit simplicity.
Data Source
AI summary
Disclosed herein are wireless transceivers with switches to reduce harmonic leakage. The devices are configured to transmit and receive signals in a first frequency band and a second frequency band. The devices selectively decouple a power amplifier from a duplexer to reduce harmonic leakage into a receiving system. The decoupling is accomplished using a switch, the switch being operated responsive to a band select signal indicating the second frequency band as a receive band but not a transmission band and the first frequency band as a transmission band where the first frequency band has at least one harmonic that lies within a downlink sub-band of the second frequency band.