Shared IDT Multiplexer Layout for Multiband Attenuation
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Solution Overview
Problem
In multiband mobile phone systems, the increased number of additional filter circuits required for sufficient attenuation in different frequency bands leads to a higher number of reflectors and IDTs, resulting in a larger multiplexer size.
Innovation Solution
A multiplexer configuration with three or more filter circuits and a shared additional circuit that includes three or more IDTs and two reflectors, connected in parallel to the first and third filter circuits, reduces the total number of reflectors and IDTs by providing equivalent attenuation functions to two additional circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional circuits are connected to each filter circuit to secure attenuation in attenuation bands, then attenuation performance is improved, but the total number of reflectors or IDTs increases
Solution Approach 1:
The patent combines multiple additional circuits into a single shared additional circuit that is connected in parallel to multiple filter circuits. This shared circuit includes multiple IDTs (Interdigital Transducers) that can be selectively activated to provide attenuation for different filter circuits, thereby reducing the total number of reflectors and IDTs compared to having separate additional circuits for each filter.
Solution Approach 2:
The shared additional circuit is designed to serve multiple filter circuits simultaneously. It includes a plurality of IDTs that can be activated based on which filter circuit requires attenuation, making the additional circuit universal and multi-functional rather than dedicated to a single filter circuit.
2Reliability
If multiple additional circuits are connected correspondingly to multiple filter circuits, then attenuation in each attenuation band is secured, but the multiplexer size increases
Solution Approach 1:
The patent merges multiple separate additional circuits into one shared additional circuit structure. This consolidation reduces the overall area occupied by additional circuits and reflectors, thereby reducing the total multiplexer size while maintaining the ability to provide attenuation for multiple filter circuits through the shared IDTs.
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 configuration reduces the size of the multiplexer by minimizing the number of reflectors and IDTs while maintaining sufficient attenuation in the attenuation bands outside the pass bands of the filter circuits.
Implementation Method 1
a plurality of IDTs (InterDigital Transducer) included in the additional circuit
Implementation Method 2
two reflectors on both outer sides of the three or more IDTs in the first direction
Data Source
AI summary
A multiplexer includes first, second, and third filter circuits, and an additional circuit, at least a portion of which is connected in parallel to each of the first, second, and third filter circuits. The additional circuit includes first, second, and third IDTs and two reflectors. The first IDT is connected to a path connecting a first terminal and the first filter circuit or a path extending through an inside of the first filter circuit. The third IDT is connected to a path connecting a third terminal and the third filter circuit or a path extending through an inside of the third filter circuit. The second IDT is connected to a path connecting the first filter circuit and a common terminal, a path connecting the third filter circuit and the common terminal, or a path connecting the second filter circuit and the common terminal.