Full-Duplex RF Paths with Impedance-Based TX-RX Isolation
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Solution Overview
Problem
Full duplex operation in small apparatuses faces challenges due to insufficient isolation between transmission and reception paths, leading to gain compression of the reception low-noise amplifier and reduced Signal-to-Noise Ratio.
Innovation Solution
The implementation of an apparatus with multiple antenna ports, power amplifiers, switching circuitry, and impedance means to create distinct impedance paths for simultaneous transmission and reception, utilizing shared impedance circuitry and phase shifters to achieve isolation between transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spatial isolation between transmission and reception is used, then isolation between transmission and reception is improved, but device size increases making it impractical for small apparatus
Solution Approach 1:
The patent segments the transmission path into multiple independent paths (first simplex path, second simplex path, first multiplex path, second multiplex path) with different impedance characteristics. By dividing the transmission function across multiple segmented paths with distinct impedances, the system achieves isolation between transmission and reception without requiring large spatial separation, thus resolving the contradiction between isolation performance and device size.
Solution Approach 2:
The patent applies local quality by providing different impedance characteristics to different transmission paths. Each path (simplex or multiplex) has specifically tailored impedance values to optimize its function. This localized impedance optimization enables effective isolation between transmission and reception paths within a compact device structure, avoiding the need for large spatial isolation.
2Device complexity
If transmitted energy enters the reception path, then device complexity is reduced, but gain compression of the reception low-noise amplifier occurs and Signal-to-Noise Ratio deteriorates
Solution Approach 1:
The patent changes the impedance parameter of different transmission paths to achieve isolation. By configuring different impedance values for simplex paths and multiplex paths, the system prevents transmitted energy from entering the reception path while maintaining relatively simple device architecture. This parameter-based isolation protects the reception low-noise amplifier from gain compression and maintains Signal-to-Noise Ratio.
Data Source
Figure 1A~2B
Figure 3A~5
Figure 6~7C
AI summary
An apparatus comprising: at least a first antenna port and a second antenna port; a power amplifier; first switching circuitry for switching between a first simplex path from the power amplifier to the first antenna port, not the second antenna port; a second simplex path from the power amplifier to second antenna port, not the first antenna port; multiplex paths from the power amplifier simultaneously to the first antenna port and the second antenna port; and impedance means for providing different impedance, for a first multiplex path from the power amplifier to the first antenna port and for a second multiplex path from the power amplifier to the second antenna port, while the first multiplex path and the second multiplex path are simultaneous multiplex paths from the power amplifier to the first antenna port and the second antenna port respectively.