Switchable Multiplexer Matching Circuits for CA Impedance Control
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Solution Overview
Problem
Existing multiplexers face challenges in achieving optimal circuit characteristics during carrier aggregation (CA) operations due to difficulties in managing impedance across different frequency bands, leading to increased insertion loss when out-of-band frequencies differ significantly between modes.
Innovation Solution
A multiplexer design incorporating a switch that connects or disconnects between multiple selection terminals and matching circuits, along with filters having different pass bands, allows for flexible operation modes by adjusting impedance through appropriate matching circuits, reducing insertion loss by maintaining impedance close to a reference value in-band while approximating an open state out-of-band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single matching circuit is used for the first filter, then the impedance can be optimized for one out-of-band frequency, but the impedance cannot be optimized for multiple different out-of-band frequencies in different CA modes
Solution Approach 1:
The patent applies dynamics by making the matching circuit configuration changeable through switch selection. The system transitions from a static single matching circuit to a dynamic configuration where the first switch selectively connects different matching circuits (first or second matching circuit) to the first filter, enabling impedance optimization for different CA modes with different out-of-band frequencies.
Solution Approach 2:
The patent changes the impedance parameters by selecting different matching circuits based on the CA mode. Each matching circuit is designed with specific impedance characteristics tailored for particular out-of-band frequencies, allowing the system to adapt impedance parameters to match different operational requirements of various CA modes.
2Loss of energy
If the impedance of the first filter is made close to reference impedance in the in-band, then insertion loss is reduced, but it becomes difficult to maintain open state impedance in out-of-band frequencies when they differ greatly between modes
Solution Approach 1:
The patent segments the impedance control function by dividing it into multiple dedicated matching circuits. Each matching circuit is specifically designed to handle particular out-of-band frequency conditions, allowing the system to segment the complex impedance control problem into manageable parts that can be selectively activated based on the CA mode.
Solution Approach 2:
The matching circuits act as intermediary elements between the first filter and the switch. These intermediaries transform the impedance characteristics to achieve the desired open state in out-of-band frequencies while maintaining reference impedance in the in-band, mediating the conflicting impedance requirements of different frequency bands.
3Reliability
If multiple matching circuits are provided with different impedance characteristics, then impedance can be optimized for different CA modes, but the device complexity increases
Solution Approach 1:
The first filter is designed with multi-functionality to serve multiple CA modes. By combining the first filter with selectively switchable matching circuits, the system achieves universal applicability across different CA modes without requiring completely separate filter designs for each mode, reducing overall system complexity.
Solution Approach 2:
The switchable architecture introduces dynamics that allow the system to adapt its complexity. While multiple matching circuits are provided, the dynamic selection mechanism ensures that only the necessary circuit configuration is active at any given time, effectively managing device complexity by activating only the required components for the current CA mode.
Data Source
AI summary
A multiplexer includes a switch that individually connects or disconnects between a common terminal and first, second, third, and fourth selection terminals, first and second matching circuits, and first, second, and third filters having different pass bands. The first selection terminal is connected to one end of the first matching circuit, the second selection terminal is connected to one end of the second matching circuit, the other end of the first matching circuit and the other end of the second matching circuit are connected to each other and to one end of the first filter, the third selection terminal is connected to one end of the second filter, and the fourth selection terminal is connected to one end of the third filter.