Branching Device with Fixed and Tunable Filters for Carrier Aggregation
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Solution Overview
Problem
Existing wireless communication devices face complexity in controlling tunable filters for carrier aggregation, which requires multiple tunable filters and often fail to meet the required filter characteristics, especially in bandpass and attenuation characteristics.
Innovation Solution
A branching device with a switch, a fixed filter circuit, and a tunable filter circuit, where the fixed filter circuit is used for carrier aggregation and the tunable filter circuit is used for single frequency band operations, simplifying the control and circuit configuration, and optionally including a matching circuit, circulators, and a tunable filter with a piezoelectric resonator and variable reactance elements to achieve low insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple tunable filters are used for carrier aggregation, then frequency band coverage is improved, but device complexity and control difficulty increase
Solution Approach 1:
The filter system is segmented into two distinct types: fixed filters with predetermined frequency characteristics and a single tunable filter. Each fixed filter is designed for specific frequency bands used in carrier aggregation, while the tunable filter handles single-band operations. This segmentation allows the system to achieve multi-band coverage without requiring multiple tunable filters, thereby reducing control complexity while maintaining frequency band coverage.
2Adaptability or versatility
If tunable filters are used for carrier aggregation, then frequency tunability is improved, but filter characteristic performance deteriorates
Solution Approach 1:
Different filter types are assigned to different operational scenarios: fixed filters with optimized frequency characteristics are used specifically for carrier aggregation operations where high-performance filtering is critical, while the tunable filter is used for single-band operations where frequency adaptability is the primary requirement. This local quality assignment ensures that each operation mode uses the most appropriate filter type, maintaining high filter characteristic performance when needed.
3Adaptability or versatility
If multiple tunable filters are configured for simultaneous transmission and reception, then carrier aggregation capability is improved, but circuit configuration complexity increases
Solution Approach 1:
The system merges multiple fixed filters for different frequency bands into a single filter circuit block that can handle carrier aggregation, combined with one tunable filter. This merging approach allows simultaneous transmission and reception across multiple frequency bands through the fixed filters while using the tunable filter for single-band operations, significantly reducing the overall number of filter components and simplifying the circuit configuration compared to using multiple independent tunable 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
The solution enables a frequency-tunable branching device compatible with carrier aggregation, simplifying control and circuit configuration, meeting the desired filter characteristics for multiple frequency bands while reducing the need for multiple tunable filters and achieving low insertion loss.
Implementation Method 1
the tunable filter circuit includes a piezoelectric resonator and a variable reactance element
Data Source
AI summary
A branching device (10) includes a switch (SW1), a fixed filter circuit (11), and a tunable filter (TF1). The switch (SW1) includes a common terminal (Ps11) and individual terminals (Ps12, Ps13). The fixed filter circuit (11) is connected to the individual terminal (Ps12) and has a fixed pass band. The tunable filter (TF1) is connected to the individual terminal (Ps13) and has a tunable pass band. The fixed filter circuit (11) includes filters (FIL1, FIL2) having different pass bands. The pass bands of the filters (FIL1, FIL2) correspond to frequency bands to be used in carrier aggregation.