RF Module Harmonic Isolation via LC Filter
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Solution Overview
Problem
The use of a common power supply for multiple front-end modules in communication devices leads to concerns about harmonic interference, which reduces reception sensitivity, and existing solutions like T-type switches increase the size and cost of the radio-frequency module.
Innovation Solution
A radio-frequency module configuration that includes a first and second external connection terminal, switches connected to these terminals, and capacitors and an inductor connected in a specific configuration to reduce harmonic interference, thereby providing isolation between front-end modules without the need for multiple switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a T-type switch is used to provide isolation between front-end modules, then harmonic interference is reduced and reception sensitivity is improved, but the number of switches increases to three per module, causing increased device size and cost
Solution Approach 1:
The patent extracts the harmful harmonic components from the power supply line by introducing a filter circuit that selectively removes frequency components above a threshold frequency. This allows the power supply to serve multiple front-end modules without transmitting harmful harmonics, eliminating the need for complex T-type switch isolation while maintaining reception sensitivity.
Solution Approach 2:
The patent introduces a filter circuit as an intermediary component between the power supply and front-end modules. This mediator selectively passes desired frequency components while blocking harmful harmonic frequencies, thereby providing isolation without requiring multiple switches per module.
2Device complexity
If a common power supply is provided for multiple front-end modules, then device size and cost are reduced, but harmonic output from one module passes through the power supply line and reduces reception sensitivity of another module
Solution Approach 1:
The patent converts the harmful harmonic frequencies into a beneficial filtering action by designing a filter circuit that uses the harmonic frequency characteristics to activate isolation. The filter is configured to detect when harmonics are present and automatically switch to an isolation mode, turning the harmful signal into a trigger for protective action.
Solution Approach 2:
The filter circuit serves as an intermediary that sits between the common power supply and multiple front-end modules, allowing the power supply to remain shared while blocking harmful harmonic transmission. This intermediary enables cost-effective common power supply usage without sacrificing reception sensitivity.
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 configuration reduces the size and cost of the radio-frequency module by minimizing the number of switches required, effectively addressing harmonic interference and improving reception sensitivity across multiple frequency bands.
Implementation Method 1
another end of the third switch is electrically connected to one end of a first capacitor
Implementation Method 2
another end of the first capacitor and another end of the second capacitor are electrically connected to one end of an inductor
Implementation Method 3
a first switch having one end electrically connected to the first external connection terminal and another end electrically connected to a first connection point
Data Source
AI summary
A radio-frequency module includes a first external connection terminal connected to a first external power supply, a second external connection terminal connected to a second external power supply, a first switch connected to the first external connection terminal and a first connection point, a second switch connected to the second external connection terminal and the first connection point, a third external connection terminal connected to the first connection point, and a third switch connected to a second connection point between the second switch and the third external connection terminal. Another end of the third switch is connected to a first capacitor. The second connection point is connected a second capacitor. Another end of the first capacitor and another end of the second capacitor are connected to an inductor. Another end of the inductor is connected to a reference potential.