Internal HIRF Detector for LRU EMI Shielding Verification
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Solution Overview
Problem
Line replaceable units (LRUs) are vulnerable to high intensity radiated fields (HIRF) due to inadequate EMI protection, leading to potential malfunctions, and existing testing methods are insufficient for ensuring the integrity of EMI filter pin connectors and chassis shielding in closed systems.
Innovation Solution
A system and method incorporating a built-in HIRF detector with an antenna configured to pick up electromagnetic fields, generating a DC signal, and a processing section to compare it with a threshold, integrated into the LRU to test the integrity of EMI filter pin connectors and chassis shielding, using a RF signal generator to simulate test signals and determine connector functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EMI filter pins and shielding are added to protect against HIRF, then reliability against electromagnetic interference improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent incorporates a built-in HIRF detector that proactively monitors electromagnetic field levels before they can cause damage to electronic components. The detector continuously measures the electromagnetic environment and provides early warning, allowing the system to take preventive action (such as shutting down sensitive circuits) before HIRF-induced malfunctions occur, thus enhancing reliability without requiring complex passive shielding structures
Solution Approach 2:
The HIRF detection system is integrated directly into the LRU chassis, allowing the unit to autonomously monitor its own electromagnetic environment and assess its vulnerability to HIRF. The detector self-evaluates the effectiveness of the EMI protection structures and can indicate when shielding or filter pins have failed, enabling the system to serve its own protection needs without external intervention
2Measurement precision
If traditional external testing methods are used to verify EMI protection, then manufacturing cost is reduced, but testing accuracy and reliability verification improve
Solution Approach 1:
The patent embeds the HIRF detector directly within the LRU chassis structure, creating a nested configuration where the detection system is integrated inside the protected unit. This nested approach allows the detector to measure electromagnetic fields at the actual location of sensitive electronics, providing accurate in-situ measurements without requiring external test equipment or disassembly of the unit
Solution Approach 2:
The built-in HIRF detector acts as an intermediary between the electromagnetic environment and the electronic components. Rather than directly exposing components to HIRF and observing failures, the detector mediates by continuously monitoring field levels and providing measurement data that indicates when protection structures are failing or when threshold levels are approached, enabling precise verification of EMI protection effectiveness
3Object-affected harmful factors
If more EMI protection elements are added, then HIRF vulnerability decreases, but ease of manufacture and assembly worsen
Solution Approach 1:
The patent extracts the HIRF detection function from external test equipment and integrates it directly into the LRU chassis as a built-in system. This extraction allows the detection capability to be incorporated during normal manufacturing processes rather than requiring separate post-assembly testing operations, improving ease of manufacture while maintaining the ability to assess HIRF vulnerability
Solution Approach 2:
The HIRF detector is designed to serve multiple functions: it monitors electromagnetic field levels, verifies the effectiveness of EMI protection structures, provides early warning of potential failures, and can indicate when shielding or filter pins have become compromised. This multi-functionality consolidates what would otherwise require multiple separate testing and protection verification systems into a single integrated component, simplifying the manufacturing process
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 effectively verifies the functionality of EMI filter pin connectors and chassis shielding, ensuring the LRU's ability to withstand HIRF, thereby preventing malfunctions and ensuring safe operation of critical systems.
Implementation Method 1
Each antenna is configured and dimensioned to pick up an electromagnetic field. The electromagnetic field induces a current in the antenna proportional to a magnitude of the electromagnetic field.
Data Source
AI summary
Various embodiments for detecting a high Intensity radiated field (HIRF) in a line replaceable unit are provided. For example, an internal detector includes at least one antenna attached to a chassis. The at least one antenna is configured and dimensioned to pick up an electromagnetic field. The electromagnetic field induces a current in the at least one antenna proportional to a magnitude of the electromagnetic field. The internal detector also includes a circuit configured to generate a DC signal based on the induced current in the at least one antenna and a processing section configured to compare the DC signal with a threshold and output a result of the comparison to a built-in test section. The internal detector may be used to test EMI filter pin connectors of a closed line replaceable unit.