Automotive Radar Module Shielding with Acute-Angled Apertures
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Solution Overview
Problem
Existing automotive radar sensor modules face challenges in providing effective EMI shielding due to their two-PCB design, which requires cumbersome and expensive connectors and cabling, making it difficult to maintain RF isolation and EMI shielding.
Innovation Solution
A single PCB design with an integrated EMI shield and radome configuration, where the EMI shield has apertures with acute-angled sidewalls and protrusions to create a shielded region for RF components, and the housing is made of conductive plastic with additional plating for enhanced shielding, eliminating the need for board-to-board connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-PCB design is used to separate RF and digital components, then functional separation is achieved, but EMI shielding becomes difficult and device complexity increases
Solution Approach 1:
The patent merges RF and digital components onto a single PCB board, eliminating the need for separate PCBs and their associated connectors and cabling. This integration simplifies the overall structure while maintaining functional separation through strategic component placement and grounding techniques.
Solution Approach 2:
The single PCB serves multiple functions: it acts as both the circuit board for mounting components and as part of the EMI shielding structure. The PCB's ground plane and metallic enclosure work together to provide both electrical connectivity and electromagnetic shielding in a unified design.
2Ease of manufacture
If connectors and cabling are used to connect two PCBs, then component separation is maintained, but manufacturing cost increases and RF isolation deteriorates
Solution Approach 1:
The patent eliminates connectors and cabling by integrating all components onto a single PCB. This removes the sources of RF interference that would otherwise be introduced by connection interfaces between separate boards, while maintaining proper signal routing and grounding throughout the unified structure.
Solution Approach 2:
The ground plane on the PCB acts as an intermediary that provides a controlled impedance path for RF signals and a reference potential for digital circuits. This intermediate layer prevents RF interference from coupling between RF and digital sections without requiring physical separation through connectors.
3Object-affected harmful factors
If conductive gaskets, RF absorbers and metal covers are added for EMI shielding, then shielding performance improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The PCB's ground plane and metallic enclosure self-generate the necessary EMI shielding without requiring additional components like conductive gaskets or RF absorbers. The ground plane provides a low-impedance path that naturally suppresses electromagnetic emissions, while the enclosure provides external shielding.
Solution Approach 2:
The patent changes the approach to EMI shielding by focusing on ground plane design parameters (trace width, spacing, grounding density) and enclosure geometry rather than adding shielding materials. By optimizing these parameters, effective EMI protection is achieved through the existing structural components.
4Device complexity
If a single PCB design is used to integrate RF and digital components, then device complexity and manufacturing cost decrease, but maintaining RF isolation becomes more challenging
Solution Approach 1:
The patent applies different design qualities to different regions of the PCB: RF components are placed in dedicated areas with specific grounding patterns and shielding, while digital components have their own grounding scheme. This local differentiation maintains RF isolation even within the integrated single-PCB structure.
Solution Approach 2:
The single PCB is functionally segmented into distinct RF and digital sections through strategic component placement, trace routing, and grounding zones. This segmentation creates natural isolation barriers without requiring physical separation, allowing both functions to coexist on one board with minimal interference.
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 module size, lowers manufacturing costs, and improves EMI shielding performance by integrating RF and DSP functions within a single PCB, minimizing external interference and emissions.
Implementation Method 1
An electromagnetic interference (EMI) shield is mounted over the first side of the PCB... The at least one protrusion on the radome and sidewalls of the at least one aperture on the EMI shield define a shielded region above the portion of the RF components
Implementation Method 2
the housing is made of plastic, which, in some embodiments, is electrically conductive. In some exemplary embodiments, an electrically conductive plating and/or paint is applied to the housing
Data Source
AI summary
An automobile radar module and method include a PCB having a first side on which RF electronic components are mounted and a second side on which digital electronic components are mounted. An EMI shield is mounted over the first side of the PCB, and a radome is mounted over the EMI shield. The EMI shield comprises an aperture exposing RF components on the first side of the PCB. The radome comprises a protrusion which protrudes into the aperture in the EMI shield. The protrusion and sidewalls of the aperture define a shielded region above the RF components on the first side of the PCB. The sidewalls extend at an acute angle with respect to a plane of the primary surface of the EMI shield, the acute angle being selected based on operational parameters of the radar module such that a predetermined shielding performance is realized.