Shielding Via Structure for RF Front-End Filter Cross-Isolation
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Solution Overview
Problem
Multi-chip front end modules face issues with cross-isolation between filters, where radiation from one filter interferes with the signal of another, leading to distortion and inefficiency in communication.
Innovation Solution
A radio frequency front end module is designed with a resin casing that includes a shield comprising a plurality of vias extending perpendicular to the substrate, which effectively separates the filters and prevents radiation interference by reflecting or refracting waves away from one filter to the other, using conductive materials like copper or gold for enhanced absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple filters are located on the same MCM module, then the module integrates multiple filtering functions, but radiation from one filter reaches and interferes with another filter causing signal distortion
Solution Approach 1:
A resin casing is introduced as an intermediary material between the filters on the MCM substrate. The resin encapsulates the filters and provides a dielectric barrier that reduces electromagnetic radiation coupling between adjacent filters, thereby preventing cross-filter interference while maintaining module integration.
Solution Approach 2:
The resin casing acts as a flexible encapsulating shell that covers and isolates the filters on the substrate. This thin film structure provides electromagnetic shielding and mechanical protection, reducing radiation leakage from one filter to another while allowing the compact MCM design to be maintained.
2Object-affected harmful factors
If wire shields are used between filters, then cross isolation is improved, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The shielding function is merged with the encapsulation structure by using the resin casing to serve both as protective coating and as electromagnetic barrier. This eliminates the need for separate wire shields between filters, reducing device complexity while maintaining cross-isolation performance.
Solution Approach 2:
The shielding function is extracted from the traditional wire-based implementation and integrated into the resin encapsulation material itself. By incorporating conductive particles or fibers into the resin, the shielding capability is embedded in the casing material, simplifying the overall device structure.
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 solution significantly improves cross-isolation between filters, reducing signal distortion and interference, allowing for more efficient and robust communication by maintaining signal integrity and preventing short circuits, with the vias arrangement optimized for specific frequency and wavelength configurations.
Implementation Method 1
prevents radiation interference by reflecting or refracting waves away from one filter to the other
Implementation Method 2
prevents radiation interference by reflecting or refracting waves away from one filter to the other
Implementation Method 3
Conductive material can be used to form the shield, and can absorb the radiation emitted by one of the filters on the MCM, and improve the cross isolation between the filters
Data Source
AI summary
A radio frequency front end module is provided which includes a first filter module disposed on a substrate, a second filter module disposed on the substrate, a resin casing disposed on the substrate and encapsulating the first and second filter modules, and a radio frequency shield disposed between the first and second filter module, wherein the shield comprises a plurality of vias formed in the resin casing and extending perpendicular to the substrate of the front end module, a method of reducing coupling between two filters on a multi-chip front end module having a resin encapsulation is also provided which includes disposing a plurality of vias in the resin encapsulation between the two filters.