RF Module Filter Placement for Multiband Isolation
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Solution Overview
Problem
In mobile communication devices, the complexity of radio-frequency front-end module configurations leads to degradation of electrical characteristics such as noise figure and gain, particularly with the advancement of multiband communication systems.
Innovation Solution
A radio-frequency module is designed with a power amplifier, a low noise amplifier, switches, and filters arranged on a module substrate, where the transmission-reception filter is positioned between the power amplifier and switches, and between the power amplifier and low noise amplifier, reducing line lengths and electromagnetic coupling to improve electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple circuit components (power amplifier, switches, filters) are packaged together in a front-end module, then multiband communication functionality is achieved, but electrical characteristics (noise figure and gain) are degraded
Solution Approach 1:
The front-end module is segmented into distinct functional blocks (power amplifier block, filter block, switch block) that are independently arranged on the substrate. This segmentation allows optimization of each block's electrical characteristics while maintaining overall multiband functionality, thereby resolving the contradiction between versatility and electrical performance.
Solution Approach 2:
Different regions of the substrate are designed with different local characteristics - the power amplifier block is positioned away from noise-sensitive components, filtering elements are strategically placed near their connection points, and grounding structures are optimized in specific areas. This local quality optimization maintains high electrical characteristics while achieving multiband communication capability.
2Area of stationary object
If circuit components are arranged closely to reduce module size, then integration density is improved, but electromagnetic coupling and stray capacitance increase
Solution Approach 1:
Grounding structures and shielding elements are introduced as intermediary components between the power amplifier, filters, and switches. These intermediaries provide electromagnetic isolation while maintaining compact overall dimensions, thus reducing harmful coupling effects without sacrificing integration density.
Solution Approach 2:
The layout strategy utilizes vertical layering and three-dimensional substrate utilization to separate components that would be too close in a purely two-dimensional arrangement. By employing via holes, stacked configurations, and multi-layer routing, the design achieves electromagnetic isolation while maintaining a compact footprint.
Data Source
AI summary
A radio-frequency module includes a power amplifier, a low noise amplifier, a first switch connected to an antenna connection terminal, a first filter, and a module substrate. The first filter has a passband including a first communication band for Time Division Duplex, has a first end connected to the antenna connection terminal via the first switch, has a second end connected to an output terminal of the power amplifier or an input terminal of the low noise amplifier. The module substrate has the power amplifier, the low noise amplifier, the first switch, and the first filter arranged thereon. The first filter is arranged between the power amplifier and the first switch and between the power amplifier and the low noise amplifier in a plan view of the module substrate.