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1. What challenges does common mode inductor design face in millimeter-wave devices?
2. What are the material options for bendable common mode inductors in flexible electronic devices?
3. What are the application prospects of superconducting common mode inductors in extreme environments?

China: Risk Classification System for Categories I, II, and III
According to the Medical Device Regulation (MDR 2017/745), the European Union classifies medical devices into Class I, Class IIa, Class IIb, and Class III, with risks gradually increasing

​1. What are possible reasons for severe heating of common mode inductors? How to troubleshoot?​
Answer: Possible reasons:

Excessive differential mode current: Common mode inductors have weak suppression capability for differential mode current. If differential mode current in the circuit exceeds design values, it increases copper loss (I²R) in windings, causing heating.
Core saturation: When common mode current or differential mode current is too high, magnetic flux density in the core exceeds saturation point, permeability drops sharply, and eddy current losses increase dramatically, causing core heating.
· Abnormal winding resistance: Winding wires are too thin, local short circuits or poor contact during winding.

What is the area with the most frequent lightning activity in the world? It is Lake Maracaibo in Venezuela Core data and phenomenon characteristics According to NASA's research, Lake Maracaibo experiences an average of 233 lightning strikes per square kilometer per year, far exceeding other regions. This data is 1.5 times that of the Congo Basin (recorded 158 square kilometers per year in Kifka village in 2004) and is also the "Lightning Capital" of Florida, United States; Orlando approximately 10 times per square kilometer per year

1. What fixture should be used for insertion loss testing of common mode inductors? Why?​
Answer: Insertion loss testing of common mode inductors typically uses 50Ω standard coaxial fixtures (such as BNC or SMA interface fixtures), and in some scenarios, they are used in conjunction with LINE IMPEDANCE STABILIZATION NETWORK (LISN). Reason: According to EMC testing standards (such as CISPR 16, IEC 61000-4-6), the characteristic impedance of the testing system needs to be unified to 50Ω.

​Question 1. How to optimize interference suppression above 10MHz through the combination of common mode inductors and Y capacitors?
Answer: Common mode inductors suppress interference through high common mode impedance from low to medium-high frequencies (e.g., below 1MHz), but at high frequencies (above 10MHz), impedance decreases due to parasitic capacitance (between windings, between windings and core), weakening suppression effect. Y capacitors (usually ceramic capacitors, such as MLCC) have low equivalent series resistance (ESR) and parasitic inductance (ESL), providing low impedance paths in high-frequency bands to divert common mode interference to ground. Optimization methods:
Capacitance selection:

The current US tariff strategy is based on a core fallacy that misjudges the complex reality of the global semiconductor industry. This self inflicted wrong policy did not lead the United States to victory, but instead resulted in strategic failure in its technological competition with China

1. What is the optimal distance between common mode inductors and X capacitors? Why?​
Answer:
The optimal distance between common mode inductors and X capacitors is generally recommended to be controlled within 3-5cm. The reason is that common mode inductors mainly suppress common mode interference, while X capacitors mainly filter differential mode interference. The two need to work together to form an EMI filter.
If the distance is too far, parasitic inductance between leads increases, causing impedance matching of the filter network in high-frequency bands (e.g., above 100MHz) to be disrupted, and interference signals may "bypass" the filter through parasitic parameters...

1. What special parameter requirements do common mode inductors need to meet in 5G base station power supplies?​
Answer:
High-frequency response and low parasitic capacitance: Need to maintain high impedance (e.g., above 1000Ω) in frequency bands above 100MHz, parasitic capacitance needs to be <10pF to avoid high-frequency signal leakage.
High saturation current: Meet large current requirements of base station power supplies (e.g., above 10A). Core materials preferably nanocrystalline or iron silicon aluminum to balance saturation characteristics and high-frequency loss.
Wide temperature range: Operating temperature needs to cover -40°C to +85°C, some outdoor base stations require...