Parallel Through-Hole Signal Paths for HF Module Impedance Matching
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Solution Overview
Problem
High frequency modules with layered substrates and through holes in signal transmission lines face challenges in achieving impedance matching due to varying inductance, which affects the module's characteristics and performance.
Innovation Solution
The implementation of parallel signal paths formed using through holes within the layered substrate to connect conductor layers, reducing the inductance of the signal transmission line and maintaining impedance matching between circuit components and external circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If through holes are used to connect conductor layers in the layered substrate, then circuit components can be connected vertically through the substrate, but the inductance of the signal transmission line increases due to the through holes
Solution Approach 1:
The signal transmission line is divided into multiple segments by introducing intermediate conductor layers between the first and second conductor layers. Instead of using a single through hole that spans the entire substrate thickness, the connection path is segmented into multiple shorter through holes separated by intermediate conductor layers, thereby reducing the total inductance of the transmission line.
Solution Approach 2:
The patent transitions from a single-layer conductor connection to a multi-layer conductor structure. By adding intermediate conductor layers at different heights within the substrate, the connection path is extended into the vertical dimension, creating multiple parallel conduction paths that reduce overall inductance while maintaining the through-substrate connection functionality.
2Ease of operation
If a long signal transmission line is used to connect an element on the top surface to a terminal on the bottom surface, then connection is achieved, but the inductance of the transmission line increases significantly
Solution Approach 1:
The patent applies different conductor layer configurations at different locations along the transmission path. Intermediate conductor layers are strategically positioned at specific heights within the substrate to provide local impedance control and reduce inductance in critical sections of the transmission line, while maintaining overall connection functionality.
Solution Approach 2:
By introducing intermediate conductor layers at different vertical positions within the substrate, the patent creates a three-dimensional transmission path that reduces the effective length of the signal path. This multi-level conductor structure allows the signal to transition between layers, effectively shortening the total path length and reducing inductance compared to a single-plane long transmission line.
Data Source
AI summary
A high frequency module incorporates a layered substrate. The layered substrate has a bottom surface and a top surface. Terminals are disposed on the bottom surface. SAW filters and inductors are mounted on the top surface. The layered substrate incorporates: a first conductor layer connecting the SAW filters to the inductors; a second conductor layer connected to the terminals and disposed at a location closer to the bottom surface than the first conductor layer; and a plurality of parallel signal paths each of which is formed using at least one through hole provided inside the layered substrate and each of which connects the first and second conductor layers to each other.