Acoustic Wave Multiplexer Split Across Dies for Compact RF Filtering
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Solution Overview
Problem
Current acoustic wave devices for radio frequency filters in mobile devices face challenges in reducing size and manufacturing cost while maintaining high power durability and low loss filter performance, particularly due to inefficiencies in combining different filter types on separate dies.
Innovation Solution
The use of a multiplexer configuration that combines a multilayer piezoelectric substrate die with a temperature-compensated surface acoustic wave die, where the first die generates acoustic waves with a velocity greater than 3800 m/s and the second die generates waves with a velocity less than 3500 m/s, allowing for a duplexer design that reduces overall size and manufacturing costs by integrating transmission and reception filters on separate dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If different filter types are combined on separate dies, then device size is reduced, but manufacturing complexity increases
Solution Approach 1:
The device is divided into separate dies, each containing specific filter types (transmission filters on first die, reception filters on second die). This segmentation reduces the overall device volume while allowing independent optimization and manufacturing of each die, thereby managing complexity through modular design.
Solution Approach 2:
Each die is designed to perform multiple functions within its structure. For example, the first die contains both transmission bandpass filters and transmission highpass filters, while the second die contains reception bandpass filters and reception highpass filters. This multi-functionality reduces the number of separate components needed, thereby reducing overall device size while maintaining functional integration.
2Ease of manufacture
If different filter types are combined on separate dies, then manufacturing cost is reduced, but integration complexity increases
Solution Approach 1:
By segmenting the device into separate dies with specific filter types, each die can be manufactured using optimized processes for that particular filter configuration. This reduces manufacturing cost per die while the overall integration complexity is managed through standardized inter-die connections and packaging.
Solution Approach 2:
The patent uses identical or similar filter designs (bandpass and highpass filters) across different dies, allowing for standardized manufacturing processes and component reuse. This copying of proven designs reduces development and manufacturing costs while maintaining consistent performance across the device.
3Reliability
If transmission and reception filters are integrated on separate dies, then power durability is improved, but device area increases
Solution Approach 1:
The patent combines transmission filters (bandpass and highpass) on the first die and reception filters (bandpass and highpass) on the second die, then integrates these dies into a single packaged device. This merging approach improves power durability by separating high-power transmission paths from sensitive reception paths, while the compact packaging minimizes the overall device area.
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional stacked configuration with multiple dies vertically arranged. This dimensional change allows transmission and reception filters to be physically separated in the vertical dimension, improving power durability through isolation, while the overall footprint area is minimized through vertical stacking.
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 effectively reduces the size of the acoustic wave device by up to 20% and maintains high power durability, achieving efficient filter performance with reduced manufacturing costs by integrating different filter types on separate dies.
Implementation Method 1
The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer on which the interdigital transductor electrode is disposed
Implementation Method 2
Surface acoustic wave filters operate by converting electrical energy into acoustic or mechanical energy on a piezoelectric material
Data Source
AI summary
An acoustic wave device is disclosed. The acoustic wave device can include a first multiplexer that has a first portion and a second portion. The acoustic wave device can include a second multiplexer that has a third portion and a fourth portion. The first portion and the third portion are formed in a first die. The second portion and the fourth portion are formed in a second die that has a different physical structure from the first die.