RF Multiplexer Coupling Circuit for Carrier Aggregation Loss Reduction
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Solution Overview
Problem
Conventional multiplexers experience performance degradation and increased losses when configured to support multiple frequency bands due to impedance mismatches and the addition of phase shifters, which further increase losses.
Innovation Solution
A multiplexer design incorporating a coupling circuit with switches and a phase shifting component that allows for optimized impedance management across multiple frequency bands, minimizing losses through parallel and series configurations in carrier aggregation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multiplexers are configured to support multiple frequency bands, then the adaptability is improved, but the insertion loss increases and impedance matching deteriorates
Solution Approach 1:
The patent implements dynamic reconfiguration of the multiplexer circuit using switches (e.g., switch 526, switch 528) that can change the circuit topology between different operating modes. In non-carrier aggregation mode, the circuit operates with certain switches open/closed to optimize for single-band performance. In carrier aggregation mode, the switches reconfigure the circuit to parallel or series connections of signal processing components, dynamically adapting the impedance and signal paths to minimize insertion loss for multiple frequency bands simultaneously.
Solution Approach 2:
The patent changes the electrical parameters of the multiplexer by reconfiguring the impedance values through different switch states. The coupling circuit (502) and signal processing components (506, 508, 510) have their effective impedance values adjusted by opening or closing specific switches, allowing the system to optimize impedance matching for different frequency band combinations. This parameter change enables the system to maintain low insertion loss when transitioning between single-band and multi-band carrier aggregation modes.
2Adaptability or versatility
If phase shifters are added to support multiple frequency bands, then the adaptability is improved, but the device complexity and energy loss increase
Solution Approach 1:
The patent makes the existing signal processing components (filters 506, 508, 510 and coupling circuit 502) multi-functional by reconfiguring their connections through switches. Instead of adding dedicated phase shifters for each frequency band, the same components serve multiple frequency bands by changing their interconnection topology. The coupling circuit can operate in different configurations (parallel, series, or combinations) to handle various frequency band combinations, making the existing components universal rather than requiring band-specific additions.
Solution Approach 2:
The patent creates multiple signal paths that are essentially copies of the same signal processing chain (coupling circuit followed by filter), where each path is optimized for specific frequency bands. In carrier aggregation mode, multiple switched paths are activated in parallel, providing copied signal processing functionality for different bands without requiring completely separate dedicated circuits for each band, thus reducing overall complexity compared to fully independent band handling.
Data Source
AI summary
A radio frequency multiplexer including a signal node to receive and/or transmit radio frequency signals, a first signal processing component to pass frequencies in a first band and reject frequencies in a second band, a second signal processing component to pass frequencies in the second band and reject frequencies in the first band, and a coupling circuit. The coupling circuit is coupled to the signal node and the first and second signal processing components and configured to couple the first signal processing component and the second signal processing component to the common signal node and in parallel with one another in a first mode, and to couple only the second signal processing component to the signal node in a second mode with the second signal processing component being coupled in series with the first signal processing component between the first signal processing component and the signal node.