LC Filter Integration in Acoustic Wave Multiplexer Receive Path

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Solution Overview

Problem

Existing multiplexers face challenges in enhancing attenuation on the receive path side in a specific frequency range, particularly when using acoustic wave filters, as they struggle to effectively separate communication bands, leading to interference and reduced reception quality.

Innovation Solution

Incorporating an LC filter on the receive path in conjunction with an acoustic wave filter, which improves attenuation in the pass band of the second filter, allowing for better separation of communication bands and reducing interference between transmit and receive signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an acoustic wave filter is used as the first filter to pass receive signals, then the filter can effectively pass the receive signal in the first pass band, but it is difficult to increase attenuation in frequency ranges separated from the pass band

Engineering Contradiction:

Improvereceive signal passing capabilityVSAvoidattenuation in separated frequency range

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines an acoustic wave filter and an LC filter in series on the receive path. The acoustic wave filter passes the receive signal in the first pass band, while the LC filter provides additional attenuation in frequency ranges separated from the pass band, achieving both functions simultaneously

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The LC filter serves multiple functions: it provides attenuation in separated frequency ranges and also contributes to overall signal filtering, making the filter system more versatile in handling different frequency requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively enhances attenuation on the receive path side, improving signal quality and reducing the impact of transmit signals on reception, thereby enhancing the overall performance of multiplexers in carrier aggregation modes.

Implementation Method 1

The first filter 21 is an acoustic wave filter disposed on a receive path R1 connecting the common terminal 10 and the first terminal 11

Methodology Applied

Scientific EffectAcoustic wave filter: Surface Acoustic Wave

Implementation Method 2

The multiplexer 1 further includes an LC filter 23. The LC filter 23 is disposed on the receive path R1 connecting the common terminal 10 and the first terminal 11

Methodology Applied

Scientific EffectLC filter: Filter (electronic)

Data Source

PatentUS12132504B2Multiplexer, radio-frequency module, and communication apparatus

Publication Date: 2024.10.29 MURATA MFG CO LTD

AI summary

Attenuation on a receive path side in a pass band of a second filter is improved in a case where a first filter, which passes a receive signal, is an acoustic wave filter. A multiplexer includes a common terminal, a first terminal, a second terminal, a first filter, and a second filter. The first filter is an acoustic wave filter disposed on a receive path connecting the common terminal and the first terminal and passes a receive signal. The second filter is disposed on a transmit path connecting the common terminal and the second terminal and passes a transmit signal. The multiplexer further includes an LC filter. The LC filter is disposed on the receive path connecting the common terminal and the first terminal.