Duplexer Ground Path Layout for Signal Isolation on Circuit Substrates
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Solution Overview
Problem
Existing circuit modules with duplexers experience undesirable interference between different types of signals, which is not effectively mitigated by current technologies.
Innovation Solution
A circuit module configuration that includes a duplexer and a circuit substrate with specific electrode arrangements and signal paths, utilizing filters and ground conductors to separate and reduce interference between transmission and reception signals, with the ground path being capacitively coupled to the signal paths to enhance isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a duplexer is mounted on a circuit substrate to separate transmission and reception signals, then signal separation is achieved, but undesirable interference is generated between the signals
Solution Approach 1:
The ground external electrodes are divided into multiple groups, with each group connected to a separate ground path. This segmentation allows different ground paths to serve different signal paths, reducing mutual interference between transmission and reception signals while maintaining effective ground references for each.
Solution Approach 2:
Multiple ground paths act as intermediaries between the ground external electrodes and the ground conductor. These ground paths provide dedicated return paths for different signals, preventing direct coupling and interference between transmission and reception circuits while maintaining ground potential stability.
2Device complexity
If ground external electrodes are connected directly to the ground conductor, then grounding is simplified, but electromagnetic coupling and interference occur between signal paths
Solution Approach 1:
The grounding structure is segmented into multiple ground paths, each serving specific signal paths. This prevents the formation of large current loops that cause electromagnetic coupling, while maintaining adequate grounding for each signal group.
Solution Approach 2:
Different ground paths provide localized grounding with different impedance characteristics optimized for their respective signal paths. Transmission signals receive grounding optimized for high current handling, while reception signals receive grounding optimized for low noise, reducing electromagnetic coupling between the two.
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
Significantly reduces and prevents undesirable interference between transmission and reception signals, as demonstrated by improved isolation characteristics and pass band characteristics in simulation models.
Implementation Method 1
a second ground path that is connected to the substrate top surface ground external electrode which is not connected to the substrate bottom surface ground external electrode and that is electromagnetically coupled to the second signal path or the third signal path
Data Source
AI summary
A circuit module includes a duplexer and a circuit substrate. A first signal path connects a first external electrode to a second external electrode. A second signal path connects a third external electrode to a fourth external electrode. A third signal path connects a fifth external electrode to a sixth external electrode. A first ground path connects a seventh external electrode to an eighth external electrode. A second ground path is connected to a ninth external electrode and is capacitively coupled to the second signal path.