High-Frequency Module Filter Grounding With a Common Inductor
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Solution Overview
Problem
In high-frequency modules, the filter characteristics are often deteriorated when a mounting substrate and a filter are provided, leading to suboptimal performance in communication devices.
Innovation Solution
A high-frequency module design that includes a mounting substrate with a common inductor connected to both series and parallel arm resonators, improving filter characteristics by enhancing signal attenuation and isolation between frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a filter is mounted on a mounting substrate, then the filter can be integrated into the communication device, but the filter characteristics are deteriorated
Solution Approach 1:
A common inductor is introduced as an intermediary component between the parallel arm resonators and the ground terminal. This inductor serves as a mediator that improves signal attenuation without directly modifying the resonators or the substrate, thereby maintaining filter characteristics while achieving integration
Solution Approach 2:
The inductance value of the common inductor is optimized to achieve the desired signal attenuation. By adjusting the inductance parameter, the filter characteristics are improved while maintaining the integrated structure on the mounting substrate
2Reliability
If ground terminals are provided on the mounting substrate, then signal reference is improved, but signal attenuation is insufficient
Solution Approach 1:
The common inductor acts as an intermediary between the ground terminals and the parallel arm resonators, enhancing signal attenuation while preserving the ground reference function. This mediator component allows both ground reference and signal attenuation to coexist effectively
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
The proposed design enhances filter characteristics by improving signal attenuation and isolation, particularly in the 2.4 GHz band for Wi-Fi communication, thereby maintaining communication quality.
Implementation Method 1
A first end of the common inductor is connected to all of the plurality of parallel arm resonators, and a second end of the common inductor is connected to the ground terminal
Implementation Method 2
The mounting substrate includes a via conductor extending between the first main surface and the second main surface. A first end of the via conductor is connected to all of the plurality of ground terminals, and a second end of the via conductor is connected to the ground terminal
Data Source
AI summary
A high-frequency module includes a mounting substrate, a filter, and a common inductor. The mounting substrate includes a first main surface and a second main surface facing each other. The filter includes series arm resonators and parallel arm resonators, and is disposed on the first main surface. The mounting substrate includes a ground terminal on the second main surface. A first end of the common inductor is connected to all of the parallel arm resonators. A second end of the common inductor is connected to the ground terminal.