Shared-Antenna Multiplexer Layout for Low-Loss GPS Reception
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Solution Overview
Problem
Existing multiplexers for mobile communications devices that share a common antenna for GPS and radio receivers suffer from signal attenuation due to additional filtering components, which can weaken already weak GPS signals.
Innovation Solution
A multiplexer design with a diplex filter in one branch and no additional components in the other branch directly couples the antenna to the GPS sub-system, reducing signal attenuation and minimizing component count, thereby improving GPS signal quality and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If filters are added in both branches to selectively couple antenna to sub-systems according to frequency, then signal frequency separation is improved, but signal attenuation increases
Solution Approach 1:
The patent removes the filter from the second branch, extracting only the necessary filter component from the symmetric dual-filter architecture. This leaves the filter only in the first branch, thereby reducing total signal attenuation while maintaining frequency separation functionality through the diplexer's inherent properties.
Solution Approach 2:
The patent applies different configurations to different branches: the first branch contains a filter for signals in the first frequency band, while the second branch has no filter for signals in the second frequency band. This local differentiation optimizes each branch for its specific function, reducing overall signal loss.
2Measurement precision
If filters are added in both branches to selectively couple antenna to sub-systems, then frequency selectivity is improved, but device complexity increases
Solution Approach 1:
The patent extracts one filter from the dual-filter configuration, leaving only a single filter in the first branch. This reduction in component count simplifies the device while the diplexer structure maintains the necessary frequency selectivity functionality.
Solution Approach 2:
The diplexer structure performs multiple functions: it provides frequency-based signal routing and replaces the need for a filter in the second branch. This multi-functionality allows the system to maintain frequency selectivity with fewer components.
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
This design enhances GPS signal reception by minimizing additional attenuation, allowing for better performance at the expense of reduced GSM signal strength, which is acceptable given the typically stronger GSM signals, and offers a cost-effective and flexible design with fewer components.
Implementation Method 1
the first branch comprises a filter for attenuating received signals in the second frequency band
Data Source
AI summary
A multiplexer for a device capable of receiving signals in first and second frequency bands, the multiplexer comprising a first branch for connecting an antenna to a first sub-system configured to process received signals in the first frequency band, a second branch for connecting the antenna to a second sub-system configured to process received signals in the second frequency band, wherein the first branch comprises a filter for attenuating received signals in the second frequency band and the second branch couples the antenna directly to the second sub-system.