PCB SAW Oscillator Module Packaging Without Clean Room Assembly
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Solution Overview
Problem
Current surface acoustic wave (SAW) oscillator technologies face challenges in cost and size reduction, particularly for high-frequency applications above 300 MHz, and require complex packaging and handling processes that increase manufacturing costs and limit miniaturization due to sensitivity to dust contamination.
Innovation Solution
A compact SAW oscillator module with a substrate-based design using a printed circuit board (PCB) that integrates pre-packaged components with castellations for electrical connections, eliminating the need for clean room assembly and seam welding, allowing for mass production at lower costs and smaller sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ceramic packaging with clean room assembly is used for SAW oscillators, then manufacturing precision is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The module separates the SAW resonator mounting surface from the electrical connection areas by using opposite faces of the substrate. The resonator is mounted on one face while castellations for electrical connections are formed on the opposite face, eliminating the need for complex clean room assembly and interconnection structures.
Solution Approach 2:
The invention extracts the electrical connection function from the same plane as the resonator mounting, placing castellations on the opposite face of the substrate. This eliminates the need for complex wire bonding or flip-chip interconnections required in conventional designs where both functions share the same plane.
2Reliability
If ceramic modules with hermetic sealing are used, then reliability is improved, but module size increases
Solution Approach 1:
The invention eliminates the separate hermetic sealing structure by integrating the substrate itself as both the mounting platform and the sealing element. The opposite-face configuration allows the substrate edges to naturally seal the cavity without requiring additional sealing layers or complex assembly steps.
Solution Approach 2:
The substrate acts as a thin-film structure that provides both mechanical support and hermetic sealing. By using the substrate's own structure rather than adding separate sealing components, the module achieves compact dimensions while maintaining reliability.
3Ease of manufacture
If standard PCB assembly methods are used, then ease of manufacture is improved, but manufacturing precision deteriorates due to dust contamination
Solution Approach 1:
The invention divides the substrate into two distinct functional faces: one dedicated to resonator mounting and the other to electrical connections via castellations. This segmentation allows standard PCB assembly methods to be used for both functions independently, eliminating the need for specialized clean room procedures while maintaining frequency precision.
Solution Approach 2:
The castellations serve as an intermediary structure that provides both mechanical support and electrical connection. By forming these castellations on the opposite face from the resonator mounting surface, the invention enables conventional PCB assembly techniques to be applied without exposing the sensitive resonator to dust contamination.
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 PCB-based SAW oscillator module achieves reduced size and cost while maintaining performance, enabling efficient high-frequency operations and simplifying manufacturing processes, thus addressing the limitations of conventional ceramic-based modules.
Implementation Method 1
surface acoustic wave (SAW) oscillator
Data Source
AI summary
A module for a surface acoustic wave oscillator includes a substrate having a top surface, a bottom surface and peripheral side faces. Several castellations are located about the outer peripheral side faces thereof. The castellations form an electrical connection between the top and bottom surfaces of the substrate. Connection pads are mounted on the top surface and are adapted for connection to the castellations. An oscillator circuit and a surface acoustic wave device are mounted on the top surface and connected to the connection pads. A cover is mounted over the substrate and has at least one tab adapted to be fitted within a respective one of the castellations. The overall module with the cover has a dimension of approximately 5 mm in width, 7 mm in length, and 2.7 mm in height.