High Frequency Connector Common Mode Choke Coil EMI Suppression
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Solution Overview
Problem
High frequency Ethernet signals transmitted through unshielded twisted pair (UTP) cables are prone to electromagnetic interference (EMI) due to the lack of a metal shielding layer, causing common mode noise that interferes with other electronic apparatuses, and existing solutions do not effectively address this issue.
Innovation Solution
A high frequency connector equipped with a common mode choke coil (CMC) featuring a grounded center tapped line that directs radiation generated by common mode signals to the ground, preventing interference with differential mode signals and reducing EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal shielding layer is added to the UTP cable, then EMI protection is improved, but cost and cable complexity increase
Solution Approach 1:
The invention extracts the shielding function from the cable structure and relocates it to the connector. The metal shield is positioned only at the connector end where signals are transmitted and received, separating the shielding function from the entire cable length. This reduces cable complexity while maintaining EMI protection at critical points.
Solution Approach 2:
The invention introduces a common mode choke coil as an intermediary component between the UTP cable and the connector. This CMC acts as a mediator that suppresses common mode noise generated by the cable, providing EMI protection without requiring the cable itself to have complex shielding structures.
2Object-affected harmful factors
If a common mode choke coil is added to the connector, then common mode noise attenuation is improved, but radiation from the CMC may interfere with differential mode signals
Solution Approach 1:
The invention extracts the radiation problem from the CMC by introducing a dedicated ground reference. The ground reference line separates the radiation path from the signal transmission path, taking the harmful radiation effect out of the signal pathway and directing it to ground.
Solution Approach 2:
The invention converts the harmful radiation from the CMC into a beneficial grounded reference. By providing a ground reference line connected to the CMC, the radiation that would otherwise interfere with differential mode signals is redirected to ground, where it becomes harmless. The potential difference between the CMC and ground creates a useful reference for noise suppression.
3Reliability
If signal conditioning is used to deal with UTP cable noise, then signal quality is improved, but additional components and complexity are introduced
Solution Approach 1:
The invention makes the connector multi-functional by integrating both connection and noise suppression functions. The common mode choke coil and ground reference are built into the connector structure, allowing it to perform both signal transmission and common mode noise suppression simultaneously, eliminating the need for separate signal conditioning components.
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 attenuates common mode signal energy by converting it into heat and radiation, which is dissipated to the ground, thereby reducing EMI and protecting differential mode signals from interference.
Implementation Method 1
the common mode signals transmitted by the wires L1 and L2 cause apparent variation in resistance when flowing through CMC1. As such, energy of the common mode signals in the wires L1 and L2 is converted into heat and radiation and attenuated thereby due to return loss
Implementation Method 2
A high frequency connector equipped with a common mode choke coil (CMC) featuring a grounded center tapped line that directs radiation generated by common mode signals to the ground, preventing interference with differential mode signals
Data Source
AI summary
A high frequency connector having a CMC is provided. The high frequency connector includes an insulating housing, a plurality of interconnection terminals and a plurality of transmitting terminals. The insulating housing includes an interconnection slot for receiving a part of the interconnection electronic apparatus inserted therein. The insulating housing includes a circuit board receiving slot, which is adapted for fixing the circuit board in the high frequency connector. The interconnection terminals are respectively fixed at the insulating housing. The interconnection terminals extend through the interconnection slot and the circuit board receiving slot of the insulating housing, so as to electrically connect the interconnection slot and a circuitry of the circuit board. The circuitry at least includes a CMC having at least one grounded central tapped wire.