Differential RF Signal Splitting with LNA Switching for Compact 5G Front Ends
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Solution Overview
Problem
Existing radio frequency (RF) communication systems face challenges in efficiently managing and splitting RF signals, particularly in advanced cellular technologies like LTE-Advanced and 5G NR, due to the complexity of features such as carrier aggregation, MIMO, and beamforming, which require multiple power amplifiers and increased board space.
Innovation Solution
A front-end system is implemented in mobile devices that includes a filter to generate differential filtered RF signals, low noise amplifiers for each component, and multi-throw switches with a balun configuration to manage and split RF signals, reducing the need for multiple power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power amplifiers are used to support carrier aggregation and MIMO, then RF signal management capability is improved, but board space and device complexity increase
Solution Approach 1:
The RF signal path is segmented into differential and single-ended domains. The differential LNA outputs are separated and independently switched, allowing flexible routing to different outputs (differential or single-ended) without requiring multiple complete amplifier chains. This segmentation enables adaptability while reducing overall complexity.
Solution Approach 2:
The front-end system is designed to perform multiple functions using a unified architecture. The same differential LNA and switching network support both carrier aggregation (by splitting differential outputs) and MIMO (by providing multiple independent RF paths), eliminating the need for separate amplifier chains for each function.
2Adaptability or versatility
If multiple power amplifiers are used to support carrier aggregation and MIMO, then RF signal management capability is improved, but board space increases
Solution Approach 1:
Multiple RF functions (carrier aggregation and MIMO) are merged into a single shared front-end architecture. The differential LNA outputs are combined with a unified switching network that can route signals to multiple outputs, eliminating the need for separate amplifier chains and reducing board space requirements.
Solution Approach 2:
The system transitions from a single-ended RF architecture to a differential architecture, adding a dimensional aspect to signal processing. This differential domain allows simultaneous support for multiple functions (carrier aggregation and MIMO) through signal splitting and switching, reducing the need for additional components and board space.
3Adaptability or versatility
If signal splitting is implemented, then support for advanced RF functionalities is improved, but operational complexity increases
Solution Approach 1:
The switching network is designed to be dynamically configurable, allowing the system to adapt its signal routing based on operational mode (carrier aggregation or MIMO). The switches can be controlled to provide different connectivity patterns, enabling flexible signal splitting without requiring complex manual reconfiguration or multiple static architectures.
Data Source
AI summary
Apparatus and methods for radio frequency (RF) signal splitting are disclosed. In certain embodiments, a front-end system includes a filter that filters an RF receive signal to generate a differential filtered RF signal between a first output and a second output, a first low noise amplifier (LNA) that generates a first amplified RF signal by amplifying a first component of the differential filtered RF signal received from the first output, a second LNA that generates a second amplified RF signal by amplifying a second component of the differential filtered RF signal received from the second output, a first multi-throw switch that receives the first amplified RF signal, and a second multi-throw switch that receives the second amplified RF signal.