BAW Filter Structures for Low-Loss SHF and EHF Notch Bands
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Solution Overview
Problem
Existing acoustic device structures, particularly Bulk Acoustic Wave (BAW) and Surface Acoustic Wave (SAW) resonators and filters, face performance issues at higher frequency bands, including scaling problems and significant acoustic losses, which hinder their effectiveness in 5G cellular networks that operate at higher frequencies than 4G networks.
Innovation Solution
The development of bulk acoustic wave resonator structures with alternating axis piezoelectric layers and optimized metal electrode arrangements, including multilayer acoustic reflectors and mass-loaded shunt resonators, to enhance frequency response and reduce acoustic losses, allowing for improved performance at Super High Frequency (SHF) and Extremely High Frequency (EHF) bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SAW based resonators and filters are used for higher frequency bands, then ease of fabrication is maintained, but performance deteriorates due to scaling issues and acoustic losses
Solution Approach 1:
The device is segmented into distinct functional regions: a first region containing SAW resonators for lower frequency bands and a second region containing BAW resonators for higher frequency bands. This segmentation allows each type of resonator to operate in its optimal frequency range, maintaining both ease of fabrication for SAW devices and high performance for BAW devices in the respective frequency bands.
Solution Approach 2:
The patent transitions from a single-dimensional frequency response to a multi-dimensional frequency response by integrating both SAW and BAW resonator technologies in the same device. This allows the filter to handle multiple frequency bands (both lower and higher) simultaneously, effectively adding a frequency dimension to the device's operational capabilities.
2Reliability
If BAW based filters and resonators are used for higher frequency bands, then performance is improved, but device complexity increases
Solution Approach 1:
The device is segmented into distinct functional regions: a first region containing SAW resonators for lower frequency bands and a second region containing BAW resonators for higher frequency bands. This segmentation allows each type of resonator to operate in its optimal frequency range, maintaining both ease of fabrication for SAW devices and high performance for BAW devices in the respective frequency bands.
Solution Approach 2:
The filter device is designed with multi-functionality to handle both lower frequency bands (using SAW resonators) and higher frequency bands (using BAW resonators) within a single device structure. This universal design eliminates the need for separate filter devices for different frequency bands, thereby reducing overall system complexity despite the advanced BAW technology employed.
3Ease of manufacture
If conventional acoustic device structures are used for 5G frequency bands, then manufacturing simplicity is maintained, but acoustic losses increase significantly
Solution Approach 1:
The device is segmented into distinct functional regions: a first region containing SAW resonators for lower frequency bands and a second region containing BAW resonators for higher frequency bands. This segmentation allows each type of resonator to operate in its optimal frequency range, maintaining both ease of fabrication for SAW devices and high performance for BAW devices in the respective frequency bands.
Solution Approach 2:
The patent employs parameter changes by utilizing BAW resonator technology with specific structural modifications (such as alternating polarity piezoelectric layers and optimized electrode arrangements) in the higher frequency band region. These parameter changes in the BAW structure significantly reduce acoustic losses at 5G frequencies while maintaining manufacturing feasibility through established semiconductor fabrication processes.
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 proposed solution significantly improves the performance of acoustic devices by reducing acoustic losses and enhancing frequency response, enabling them to operate effectively in the higher frequency ranges required for 5G applications, thereby addressing the limitations of existing technologies.
Implementation Method 1
a first plurality of piezoelectric layers arranged in an alternating axis configuration, each layer of the first plurality of piezoelectric layers having a first piezoelectric coefficient and a second piezoelectric coefficient, wherein an axis corresponding to the first piezoelectric coefficient is orthogonal to an axis corresponding to the second piezoelectric coefficient
Implementation Method 2
Bulk Acoustic Wave (BAW) and Surface Acoustic Wave (SAW) resonators and filters
Implementation Method 3
multilayer acoustic reflectors
Implementation Method 4
mass-loaded shunt resonators
Data Source
AI summary
Techniques for improving acoustic wave device structures are disclosed, including filters and systems that may include such devices. An apparatus may comprise a first electrical filter including an acoustic wave device. The first electrical may having a first filter band in a Super High Frequency (SHF) band or an Extremely High Frequency (EHF) band to facilitate compliance with a regulatory requirement or a standards setting organization specification. For example, the first electrical filter may comprise a notch filter having a notch band overlapping at least a portion of an Earth Exploration Satellite Service (EESS) band to facilitate compliance with a regulatory requirement or the standards setting organization specification for the Earth Exploration Satellite Service (EESS) band.