LTCC Shielding Structure for Signal Isolation
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Solution Overview
Problem
There is a need for improved signal isolation in low temperature co-fired ceramic (LTCC) surface-mount devices, particularly for radiofrequency, microwave, and millimeter-wave signals, as existing technologies do not adequately maximize signal isolation between the input and output ports.
Innovation Solution
A shielding structure is implemented around the LTCC circuit or component, which can be external or internal, constructed from metal or metal-plated materials, providing a continuous metallic enclosure with apertures for signal transmission. This shielding structure is designed to enhance electromagnetic shielding and electrical grounding, reducing parasitic capacitance and improving signal rejection in the stopband frequency bandwidth while maintaining passband performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shielding structure is added around the LTCC device, then signal isolation is improved, but device complexity increases
Solution Approach 1:
The shielding structure is integrated with the LTCC device by forming it from the same ceramic substrate material, combining the shield into the device body rather than adding it as a separate component. This merging approach improves signal isolation while minimizing the increase in device complexity.
Solution Approach 2:
The LTCC substrate serves multiple functions: it provides the mechanical support for the circuit, acts as the shielding material to block electromagnetic signals, and maintains electrical connections through embedded conductors. This multi-functionality allows the same structure to provide both device support and signal isolation without requiring additional dedicated shielding components.
2Reliability
If the shielding structure uses continuous metal enclosure, then electromagnetic shielding is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent changes the material parameter from separate metal components to a ceramic material (LTCC) that can be formed using standard ceramic processing techniques. This allows the shielding structure to be manufactured as an integral part of the LTCC device using proven ceramic fabrication methods, reducing manufacturing complexity while maintaining effective electromagnetic shielding.
Solution Approach 2:
The shielding structure utilizes the composite nature of LTCC, combining ceramic material with embedded metallic conductors. This composite approach allows the ceramic to provide the continuous shielding enclosure while the embedded metals provide electrical connectivity, achieving both electromagnetic shielding and manufacturability through a single integrated material system.
3Ease of operation
If apertures are provided in the shielding structure for signal transmission, then signal transmission is enabled, but shielding effectiveness is reduced
Solution Approach 1:
The shielding structure has different properties in different locations: it provides continuous shielding in most areas to block electromagnetic signals, but includes localized apertures where signal transmission is required. This local differentiation allows the shield to be effective where needed while enabling signal passage at specific points without compromising overall shielding performance.
Solution Approach 2:
The apertures in the shielding structure serve as intermediaries that allow signal transmission while maintaining the overall shielding function. By strategically positioning and sizing these apertures, the design enables necessary signal communication between internal and external circuits while the surrounding continuous ceramic material maintains electromagnetic shielding effectiveness.
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 shielding structure effectively increases signal isolation and rejection of unwanted signals, enhancing the operational performance of LTCC devices by minimizing signal leakage and maintaining desired electrical performance without degrading the passband signals.
Implementation Method 1
A shielding structure is implemented around the LTCC circuit or component, which can be external or internal, constructed from metal or metal-plated materials, providing a continuous metallic enclosure with apertures for signal transmission. This shielding structure is designed to enhance electromagnetic shielding and electrical grounding, reducing parasitic capacitance and improving signal rejection in the stopband frequency bandwidth while maintaining passband performance.
Implementation Method 2
This shielding structure is designed to enhance electromagnetic shielding and electrical grounding, reducing parasitic capacitance and improving signal rejection in the stopband frequency bandwidth while maintaining passband performance.
Data Source
AI summary
An apparatus and method for shielding for surface-mount LTCC components and filters to increase the signal isolation from input signal port to output signal port, and to increase isolation from other electrical signals external to the component or filter. Some embodiments include an interposer two-sided and plated through printed circuit board to provide a constant impedance transition from a surface-mount device input and output ports to corresponding input and output connection points of a circuit on a printed circuit board onto which the device is mounted, including a ground plane transition.