Multilayer Substrate Harmonic Suppression via Ground Layer Segmentation
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Solution Overview
Problem
Conventional multilayer substrates for high-frequency signal transmission/receiving have complex patterns and shapes, leading to increased costs and manufacturing difficulties, while existing solutions for improving high-frequency characteristics complicate the substrate configuration.
Innovation Solution
A multilayer substrate design with two input side ground layers, two output side ground layers, and three or more intermediate ground layers, where the length of the intermediate region signal line is set to be an integral multiple of the half wavelength of the harmonic wave, and the input side region signal line length is based on the impedance of the harmonic wave, to simplify the configuration and enhance high-frequency performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filter circuits or matching circuits are formed on the multilayer substrate to suppress harmonic waves, then high-frequency characteristics are improved, but the pattern becomes complicated
Solution Approach 1:
The patent extracts the harmonic wave suppression function from separate filter/matching circuits and integrates it directly into the ground layer structure. By forming ground layers with specific patterns (cutouts, via holes) in the multilayer substrate, the substrate itself performs both grounding and harmonic suppression functions, eliminating the need for additional filter circuits.
Solution Approach 2:
The patent merges the grounding function and harmonic wave suppression function into a single integrated structure. The ground layers are designed with specific patterns that simultaneously provide electrical grounding and create electromagnetic shielding effects to suppress harmonic waves, combining multiple functions into one component.
2Reliability
If the inner conductive layer is exposed to contact with the casing as system ground, then good high-frequency characteristics are achieved, but the substrate shape becomes complicated
Solution Approach 1:
Instead of exposing the inner conductive layer vertically (requiring concave/stepped portions), the patent uses via holes to connect inner ground layers to outer ground layers in the vertical dimension, while maintaining a flat substrate surface in the horizontal dimension. This resolves the shape complexity issue while achieving the desired electrical connection.
Solution Approach 2:
The patent nests multiple ground layers within the multilayer substrate structure, with inner ground layers connected to outer ground layers through via holes. This creates a nested configuration where ground potential is distributed across multiple layers, achieving effective grounding without exposing inner layers to the substrate exterior.
3Reliability
If multiple ground layers are formed in the intermediate region, then harmonic wave suppression is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the ground layer into multiple distinct layers (first ground layer, second ground layer, third ground layer) positioned at different heights within the substrate. Each ground layer can be formed independently on its respective conductor layer, allowing for modular manufacturing while achieving comprehensive harmonic wave suppression through the stacked configuration.
Data Source
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AI summary
To provide a multilayer substrate for transmitting/receiving a high frequency signal, the substrate having a simplified configuration and excellent high frequency characteristics. This disclosure pertains to a multilayer substrate (10) provided with: a plurality of dielectric layers (11, 12, 13) laminated together with ground layers (20, 26, 31, 36) interposed therebetween; and a signal line (16) for inputting and outputting a signal, the signal line (16) being formed on the surface of the dielectric layer (11). The plurality of ground layers include an input-side ground layer part formed in the region on the signal-input side of the signal line, an output-side ground layer part formed in the region on the signal-output side of the signal line, and an intermediate ground layer part formed in the region between the input-side ground layer part and the output-side ground layer part. The input-side ground layer part and the output-side ground layer part each have fewer layers than the intermediate ground layer part.