In high-power radio-frequency (RF) applications, engineers often encounter the micro-discharge effect—a small-scale electrical phenomenon that can occur inside high-power cable assemblies, connectors, or other RF devices. When a micro-discharge channel forms, it may lead to partial discharge, arc activity, or insulation breakdown, reducing reliability and affecting system stability. Therefore, identifying and mitigating this effect during the design stage is essential for long-term performance.

What Is the Micro-Discharge Effect?

The micro-discharge effect refers to a localized discharge phenomenon between two metal surfaces or along a dielectric surface under RF excitation.
When electrons in a radio-frequency electric field gain sufficient energy, they collide with surrounding surfaces and produce secondary electrons, leading to a chain reaction.

Two common cases include:

1. Between metal surfaces: theelectron’s mean free path exceeds the gap distance, and its transit timecorresponds to half-cycle multiples of the RF field.
2. On dielectric surfaces: surfacecharge creates a DC field that accelerates electrons back toward thesurface, generating more secondary electrons.

At the micro-structure level, this produces local field enhancement, and once the electric-field intensity reaches a threshold, a small arc may appear within the dielectric region.

Schematic Diagram of Micro-discharge Effect Process

When Does the Micro-Discharge Effect Occur?

1. High Voltage Stress: greatervoltage increases the likelihood of discharge initiation.
2. High Resistance Dielectrics: materialssuch as PTFE or PEI restrict charge flow, allowing local chargeaccumulation.
3. Non-Uniform Electric Fields: sharpedges or gaps intensify the field, giving electrons sufficient energy tomove and trigger discharge.

Possible Impacts

• Elevated noise or harmonic distortion
• Reduced signal output or power efficiency
• Surface damage within inner cavities, shortening service life
• Increased voltage standing-wave ratio (VSWR) andsignal irregularities
• Irreversible component degradation

Connector center pin burnt

How to Suppress Micro-Discharge Breakdown

To prevent micro-discharge in high-frequency components, engineers can apply several design strategies:

1. Increase clearance and creepage distance where possible
2. Use hybrid dielectric structures for improved fielddistribution
3. Adopt stepped transition geometries to reduce localfield peaks
4. Apply weather-resistant, stablecoatings for long-term insulation protection

Focusimple specializes in microwave and RF technology research.
Our R&D team—composed of experienced engineers from leading technology firms—offers comprehensive support from product concept to testing. Drawing from extensive experience in commercial aerospace and high-power semiconductor equipment, Focusimple continuously innovates based on customer needs, delivering fast, professional, and reliable RF solutions that enhance product stability and system efficiency.