L-PA Mid RF Front-End Layout for Low-Band Link Loss Reduction

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Solution Overview

Problem

The existing radio frequency transceiving systems suffer from high link loss for low-frequency signals, leading to poor performance and inefficient communication.

Innovation Solution

A radio frequency L-PA Mid device with integrated low noise amplifier (LNA) and power amplifier modules, including duplexers, which reduces insertion loss and improves sensitivity and output power through optimized switch circuits and filter units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a multiway switch with T ports and P ports is used to transmit sounding reference signals through multiple antennas, then the antenna switching function is achieved, but the link loss for low frequency signals becomes too large

Engineering Contradiction:
Improveantenna switching functionVSAvoidlink loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent divides the radio frequency front-end module into multiple independent functional units: LNA unit, PA unit, duplexer unit, and filter unit. Each unit handles specific signal processing tasks, allowing low frequency signals to bypass unnecessary components and reducing cumulative link loss while maintaining multi-antenna switching capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary control mechanism that selectively activates different signal paths based on frequency band. For low frequency signals, the system uses a dedicated path with reduced components, while for other frequencies, the full multiway switch configuration is utilized, thus minimizing link loss for specific frequency ranges.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the radio frequency front-end module uses conventional architecture, then basic transceiving function is provided, but the performance is poor due to high link loss

Engineering Contradiction:
Improvetransceiving functionVSAvoidlink loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges the LNA and PA functions into an integrated L-PA Mid module with intermediate filtering and duplexing capabilities. This consolidation reduces the number of external connections and interfaces, thereby reducing cumulative link loss while maintaining reliable transceiving functionality across multiple frequency bands.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the architectural parameters of the radio frequency front-end by repositioning the duplexer and filter units within the signal path, specifically placing them before the power amplifier. This parameter change optimizes the signal flow for low frequency signals, reducing the number of passive components in the signal path and thereby reducing link loss.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4254808B1Radio frequency l-pa mid device, radio frequency transceiving system and communication device
Publication Date: 2026.01.28 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4254808B1 patent drawingFigure 1~3
  • EP4254808B1 patent drawingFigure 4~6
  • EP4254808B1 patent drawingFigure 7~8

AI summary

A radio frequency L-PA Mid device. The radio frequency L-PA Mid device is configured with a transmitting port, an antenna port and a plurality of receiving ports. The radio frequency L-PA Mid device comprises: a first transmitting circuit (110), which is used for performing amplification and filtering processing on a received preset low-frequency signal; a second transmitting circuit (120), which is used for performing amplification and filtering processing on a plurality of received low-band signals; a receiving circuit (130), which is connected to the plurality of receiving ports and is used for performing filtering and amplification processing on the received preset low-frequency signal and the plurality of received low-band signals; and a switch circuit (140), wherein a plurality of first ends of the switch circuit are respectively connected to the first transmitting circuit (110), the second transmitting circuit (120) and the receiving circuit (130), and a second end of the switch circuit (140) is connected to the antenna port and is used for selectively making a radio frequency path between the first transmitting circuit (110) and the antenna port, between the second transmitting circuit (120) and the antenna port and between the receiving circuit (130) and the antenna port be conducting.