RF Series Attenuator Module for Adjacent Circuit Substrates
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Solution Overview
Problem
Existing attenuator modules for bridging two transmission lines on adjacent circuit substrates require a gap in the signal line for installation, which permanently alters the signal path, making reinstallation and optimization costly and error-prone.
Innovation Solution
An attenuator module with a top-surface attenuator circuit and bottom-surface conductor pads connected via conductive vias, allowing direct placement on adjacent signal traces without altering the signal line configuration, and enabling easy rework and optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a T-shaped attenuator is installed using the conventional gap approach, then the shunt resistive element can be connected to ground, but the signal line is permanently altered making reinstallation and optimization difficult
Solution Approach 1:
The attenuator module is segmented into distinct functional components: series resistive elements on the top surface for signal attenuation, and a shunt resistive element connected to ground through a via. This segmentation allows each component to be optimized independently while maintaining overall functionality, and the module can be easily removed and reinstalled without permanent modifications to the signal line.
Solution Approach 2:
The attenuator module substrate acts as an intermediary carrier that holds all attenuator components (series resistive elements, shunt resistive element, and grounding via) in a predetermined configuration. This intermediary structure enables the attenuator to be installed as a complete module on adjacent signal traces without requiring permanent alterations to the transmission lines, facilitating easy rework and optimization.
2Ease of manufacture
If a gap is formed in the signal line for attenuator installation, then the shunt element pad can be connected to ground, but costly amplifier rework and handpicking are required
Solution Approach 1:
The attenuator module merges multiple components (series resistive elements, shunt resistive element, grounding via, and interconnectors) into a single integrated assembly mounted on a substrate. This merging allows the entire attenuator to be manufactured and tested as one unit, then installed as a complete module between adjacent signal traces without requiring gap formation or amplifier rework, thereby maintaining high production line efficiency.
3Reliability
If the shunt element pad is connected to DC ground, then the shunt element functions correctly, but the pad cannot be connected to the downstream signal path
Solution Approach 1:
The shunt resistive element is connected to ground through a via that extends vertically through the substrate, utilizing the third dimension (depth) rather than consuming horizontal signal path space. This vertical connection allows the shunt element to be properly grounded while maintaining an uninterrupted signal path on the top surface of the substrate, reducing device complexity and enabling easier installation on adjacent traces.
Data Source
AI summary
An attenuator module having an attenuator disposed on a top surface of a substrate, an input terminal at one end of the attenuator and an output terminal at an opposite end of the attenuator. A pair of spaced electrical conductor pads is disposed on a bottom surface of the substrate, a first one of the pads being disposed under the input terminal and a second one of the pads being disposed under the output terminal. A pair of conductive vias passes through the substrate, one conductive via connecting the input terminal to the first one of the pads and the other conductive via connecting the output terminal to the second one of the pads. The module may be used to interconnect two adjacent circuit substrates.