Acoustic Wave Multiplexer Layout to Limit Inter-Die Transmission-Line Loss
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Solution Overview
Problem
Existing multiplexers with acoustic wave filters face challenges in maintaining low insertion loss and high reflection coefficients due to impedance mismatches caused by transmission lines between acoustic resonators and common nodes, which can degrade filter performance and increase module size and cost.
Innovation Solution
A multiplexer design that includes acoustic wave filters with resonators on multiple dies, where resonators are connected via transmission lines to a common node, and additional resonators on separate dies to reduce the effects of transmission lines on passbands, using a series resonator configuration to enhance impedance matching and reduce insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If acoustic wave filters are implemented by a plurality of die, then device integration is improved, but impedance matching deteriorates due to transmission lines between dies
Solution Approach 1:
A switch is introduced as an intermediary component between the acoustic resonators on different dies and the common node. This switch enables selective connection of resonators to the common node, allowing impedance matching to be maintained despite the presence of transmission lines between dies. The switch acts as a mediator that compensates for the impedance degradation caused by inter-die transmission lines.
2Device complexity
If transmission lines are used to connect resonators on separate dies, then device integration is improved, but insertion loss increases
Solution Approach 1:
The switch provides dynamic control over the connection between resonators and the common node. By selectively connecting or disconnecting resonators based on operating conditions, the system can optimize performance and minimize insertion loss. The dynamic switching capability allows the system to adapt to different frequency bands and operating modes, reducing the negative impact of transmission line losses.
3Adaptability or versatility
If multiple acoustic resonators are connected to a common node via transmission lines, then filter functionality is improved, but reflection coefficient decreases
Solution Approach 1:
The switch enables dynamic reconfiguration of the filter network, allowing different combinations of resonators to be connected to the common node depending on the desired frequency response. This dynamic control maintains high reflection coefficients across multiple frequency bands by selectively activating appropriate resonator configurations, thereby preserving filter functionality while maintaining reliability.
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 achieves lower insertion loss and improved impedance matching, allowing for reduced module size and cost while maintaining high reflection coefficients across a wide bandwidth, suitable for 5G NR and 4G LTE frequency bands.
Implementation Method 1
A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate. 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
A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate.
Implementation Method 3
In BAW resonators, acoustic waves propagate in a bulk of a piezoelectric layer.
Data Source
AI summary
Aspects of this disclosure relate to a multiplexer that includes an acoustic wave filter including acoustic wave resonators on at least two die with a transmission line electrically connecting the acoustic wave resonators on the two die. The acoustic wave filter can include a plurality of acoustic wave resonators on a first die electrically connected to at least one acoustic wave resonator on a second die via the transmission line. The acoustic wave resonator on the second die can provide a relatively high impedance at a respective passband of one or more other filters of the multiplexer. This can reduce effects of the transmission line of the acoustic wave filter on a respective passband of one or more other filters of the multiplexer.