Split-Ring Resonator Ion Source With Stable RF Impedance Matching

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Solution Overview

Problem

Conventional miniaturized plasma sources, such as microstrip split-ring resonators (MSRRs), face challenges in impedance matching due to geometric factors, which vary significantly between pre-ignition and post-ignition conditions, requiring complex dynamic matching circuits, and result in minimized ion acceleration and average ion velocity.

Innovation Solution

A charged particle source with a resonator design featuring multiple power input points, offset source electrodes, and impedance matching circuits, including RF power supplies and control circuitry, to maintain well-matched impedance conditions in both discharge and non-discharge states without dynamic matching circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional MSRRs use a single feed line configuration, then the design is simple, but impedance matching varies significantly between pre-ignition and post-ignition conditions requiring complex dynamic matching circuits

Engineering Contradiction:
Improveimpedance matching adaptabilityVSAvoidmatching circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The resonator is divided into multiple segments with distinct feed line configurations. Each segment is designed to provide optimal impedance matching for specific operating conditions (pre-ignition or post-ignition), allowing the system to adapt to different discharge regimes without requiring complex dynamic matching circuits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different feed line configurations based on the discharge state. By detecting whether the resonator is in pre-ignition or post-ignition mode, the appropriate feed line is activated to maintain optimal impedance matching throughout operation.

Inventive Principle:
Principle #15Dynamics

2Speed

If conventional MSRRs use mean voltage of RF power signal equal to about 0 V, then the design is simple, but ion acceleration and average ion velocity are minimized

Engineering Contradiction:
Improveion velocityVSAvoidpower signal configuration
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The system uses periodic modulation of the RF power signal to create a time-varying electric field that accelerates ions. By applying RF power with a non-zero mean voltage during specific phases of the resonator operation, ions gain additional velocity beyond what would be achieved with a zero-mean signal.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The mean voltage of the RF power signal is changed from 0 V to a non-zero value during specific operating phases. This parameter change enables enhanced ion acceleration while maintaining compatibility with the resonator's fundamental operation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional MSRRs use dynamic matching circuits with active control systems, then impedance matching is improved, but the size, cost, and complexity increase

Engineering Contradiction:
Improveimpedance matching stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resonator system inherently provides its own impedance matching through the distributed feed line configurations. Each feed line is designed with specific geometric parameters that automatically provide optimal matching for its intended operating mode, eliminating the need for external active control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The characteristic impedance of each feed line is specifically designed to match the resonator's input impedance under different operating conditions. By adjusting the geometric parameters (width, length, position) of each feed line segment, optimal impedance matching is achieved without requiring dynamic adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 enables efficient ion extraction and acceleration, maintaining stable impedance matching across different discharge regimes, enhancing the performance of focused ion beam systems and optical spectroscopy applications.

Implementation Method 1

At resonance, the electric potential at the ends of the dipole is 180° out of phase, enabling the amplitude of the electric field between them to be amplified several orders of magnitude. Hence, with a relatively low input power, a large potential is created across the gap, and this potential is used to ignite and maintain a plasma.

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

A first conductive path from the RF power supply through the first input point can be well-matched in an absence of a discharge. A second conductive path from the RF power supply through the second input point can be well-matched in a presence of the discharge.

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

The source electrode can be disposed proximal to the first side. The source electrode can define an aperture.

Methodology Applied
Scientific EffectElectrostatic Induction: Electrostatic Induction

Data Source

PatentEP4701345A1Split ring resonator ion beam source
Publication Date: 2026.02.25 FEI CO
  • EP4701345A1 patent drawingFigure 1
  • EP4701345A1 patent drawingFigure 2A~2B
  • EP4701345A1 patent drawingFigure 3A~3B

AI summary

Embodiments of charged particle beam systems, components, and methods for extracting charged particles from a gas are described. In a first aspect, A charged particle source includes a resonator. The resonator can include a dielectric substrate defining a first side and a second side, the second side opposite the first side. The resonator can include a first conductive layer disposed on the first side. The first conductive layer can be disposed in accordance with a pattern comprising a ring portion. The pattern can define a gap in the ring portion of the first conductive layer. The resonator can also include a second conductive layer disposed on the second side. The charged particle source can also include a source electrode. The source electrode can be disposed proximal to the first side. The source electrode can be offset from the dielectric substrate.