Tunable RF Filter Architecture for Multi-Band Carrier Aggregation
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Solution Overview
Problem
Current RF front-end designs face challenges in managing multiple frequency bands and carrier aggregation use cases, leading to increased system losses, complexity, and redundancy, which result in degraded reference sensitivity and larger form factors due to the need for multiple switched filters and redundant filter circuits.
Innovation Solution
The implementation of wide band RF filters that group Carrier Aggregation combinations into frequency clusters, using tunable bandpass and bandstop filters to separate and reject interfering signals, reducing the number of filters and switches, and employing adjustable phase shifters and matching networks to optimize filter performance across multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple fixed filters are used to support multiple carrier aggregation use cases, then the number of supported frequency bands increases, but the device complexity and area increase significantly
Solution Approach 1:
The patent employs a tunable filter with variable filtering characteristics that can be dynamically adjusted to support multiple frequency bands and carrier aggregation configurations. This single dynamic filter replaces multiple static filters, reducing device complexity while maintaining versatility across different operating modes and frequency combinations.
2Adaptability or versatility
If multiple fixed filters are used to support multiple carrier aggregation use cases, then the number of supported frequency bands increases, but the area occupied by filter circuits increases
Solution Approach 1:
The patent merges the functionality of multiple fixed filters into a single tunable filter circuit. This consolidation integrates multiple filtering functions into one unified structure, significantly reducing the total area occupied by filter circuits while maintaining the ability to support multiple frequency bands through dynamic reconfiguration.
3Adaptability or versatility
If more switched filters are used to support more carrier aggregation use cases, then the flexibility in frequency planning increases, but the insertion loss increases
Solution Approach 1:
The tunable filter provides continuous or stepped adjustment of filtering characteristics without requiring switching between multiple discrete filter components. This dynamic adjustment capability maintains flexibility in frequency planning while minimizing insertion loss by avoiding the cumulative effects of multiple switched filter stages.
4Productivity
If multiple fixed filters are used, then the ability to process multiple frequency bands simultaneously is improved, but the reference sensitivity is reduced
Solution Approach 1:
By consolidating multiple filtering functions into a single tunable filter, the patent reduces the cumulative insertion loss that would otherwise degrade reference sensitivity. The unified filter structure maintains the capability to process multiple frequency bands simultaneously while preserving better signal integrity and reference sensitivity compared to cascaded fixed filters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces system complexity, area, and component count, while improving design flexibility and reference sensitivity by minimizing interference between frequency clusters and reducing insertion loss, allowing for efficient simultaneous processing of multiple frequency bands.
Implementation Method 1
bandpass filtering, using a first tunable bandpass filter, the first coupled signal to form a first tunable bandpass filtered signal
Implementation Method 2
producing a first coupled signal and a first transmitted signal from the first filtered transmitted signal using a directional coupler
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3C
AI summary
In accordance with an embodiment, a method of operating an RF system includes generating a first RF signal having a first frequency; filtering the generated first RF signal to form a first filtered transmitted signal; producing a first coupled signal and a first transmitted signal from the first filtered transmitted signal; transmitting the first transmitted signal; transmitting a second RF signal having a second frequency; bandpass filtering the first coupled signal to form a first tunable bandpass filtered signal; and measuring a parameter of the first tunable bandpass filtered signal.