RF Circuit Filter Segmentation for High-Power FDD Transmission
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Solution Overview
Problem
The application of a power class with higher maximum output power to frequency division duplex bands leads to filters entering a high-temperature state, causing degradation of transmission characteristics in radio frequency circuits.
Innovation Solution
A radio frequency circuit design that includes multiple filters and switches, allowing for the splitting and routing of transmit signals based on power class requirements, with filters specifically designed to handle different bands and power classes, and using substrates to improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power class allowing maximum output power higher than conventional levels is applied to FDD bands, then the maximum output power is improved, but the filter enters high temperature state and transmission characteristics degrade
Solution Approach 1:
The patent divides the filter into multiple filters (first filter and second filter) that operate at different power classes. The first filter handles Power class 3 signals while the second filter handles Power class 2 signals, allowing the system to achieve higher overall output power without overloading any single filter and causing temperature-related degradation.
2Power
If a power class allowing maximum output power higher than conventional levels is applied to FDD bands, then the maximum output power is improved, but the electric power handling performance enters critical state
Solution Approach 1:
The patent segments the power handling function across multiple filters with different power class ratings. The first filter is configured for Power class 3 and the second filter for Power class 2, distributing the electric power handling load to prevent any single filter from entering a critical state while maintaining high overall output power capability.
3Reliability
If multiple filters supporting different power classes are used, then transmission characteristics are maintained, but device complexity increases
Solution Approach 1:
The patent designs a circuit configuration where switches and signal paths are arranged to route different power class signals through appropriate filters. The same circuit structure handles both Power class 2 and Power class 3 signals by selectively connecting to either the first filter or second filter based on the signal type, achieving multi-functionality without requiring completely separate circuit paths.
Data Source
AI summary
A radio frequency circuit includes a power amplifier, which supports Power class 2, a first filter, which is connected to the power amplifier, which supports Power class 3, and which has a passband including the uplink operating band of Band A for FDD, a second filter, which is connected to the power amplifier, which supports Power class 3, and which has a passband including the uplink operating band of Band A, and a third filter, which is connected to the power amplifier, which supports Power class 2, and which has a passband including Band B for TDD. Assuming a transmit signal in Band A, which supports Power class 2, from the power amplifier is to be output, a transmit signal in Band A is split for output to the first filter and the second filter. Assuming a transmit signal in Band B, which supports Power class 2, is to be output, a transmit signal in Band B is output from the power amplifier to the third filter.