Fence Via-Hole Array Resonance Suppression in Wideband Magnetic Probes
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Solution Overview
Problem
Conventional magnetic probes using CB-CPW suffer from resonance issues that limit their wideband performance, leading to electromagnetic interference and compatibility challenges in near-field scanning applications.
Innovation Solution
A resonance suppression structure for wideband near-field magnetic probes is introduced, featuring a micro coaxial connector and a 4-layer PCB design with strategically placed ground via holes forming a fence via-hole array, which effectively suppresses CB-CPW resonance and extends the working band by preventing parallel-plate mode energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CB-CPW is used as a feeder in magnetic probe, then the probe can connect with microwave components conveniently and achieve wideband performance, but CB-CPW resonance occurs at high frequency limiting the working band
Solution Approach 1:
A fence via-hole array is introduced as an intermediary structure between the CB-CPW central conductor and the back metal panel. This array of via holes acts as a mediator to block the transmission of parallel-plate mode energy while maintaining the CB-CPW's wideband characteristics and connectivity functions.
Solution Approach 2:
The back metal panel is segmented into multiple sections by the fence via-hole array, which divides the continuous metal surface into discrete regions. This segmentation prevents the formation of large resonant cavities and suppresses parallel-plate mode resonance while preserving the overall CB-CPW structure's wideband performance.
2Object-affected harmful factors
If the top and bottom layers are made as metal layers to form a complete shield, then electromagnetic shielding is improved, but the probe becomes a metal resonant cavity causing resonance at high frequency
Solution Approach 1:
The fence via-hole array serves as an intermediary structure that maintains electromagnetic shielding by blocking parallel-plate mode energy transmission between the top and bottom metal layers, while preventing the formation of a complete resonant cavity that would cause high-frequency resonance.
Solution Approach 2:
The continuity of the back metal panel is extracted or interrupted by the fence via-hole array, removing the condition that creates the resonant cavity while preserving the shielding function through the via holes that block electromagnetic energy transmission.
3Adaptability or versatility
If ground via holes are added to suppress resonance, then the working band is extended, but the structure complexity increases
Solution Approach 1:
The fence via-hole array uses the existing ground plane structure and standard via hole fabrication processes to achieve resonance suppression. The via holes serve multiple functions: providing ground references for the CB-CPW, blocking parallel-plate mode energy, and extending the working band, all while utilizing conventional PCB manufacturing techniques without adding significant structural complexity.
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 proposed structure enhances the magnetic probe's sensitivity and spatial resolution while reducing electric field signal coupling, effectively moving resonance frequencies out of the working band and improving the probe's wideband performance without increasing complexity or cost.
Implementation Method 1
dealing the magnetic probe resonance is important for achieving a magnetic probe wideband performance
Implementation Method 2
The CB-CPW central conductor couples the energy to the top shield plane layer at high frequency
Implementation Method 3
The CB-CPW central conductor couples the energy to the top shield plane layer at high frequency
Implementation Method 4
Near-field scanning is an important way to solve electromagnetic interference and electromagnetic compatibility
Data Source
AI summary
The resonance structure is that two rows of ground via holes are placed symmetrically along two sides of the CB-CPW central conductor; each row of the via holes are equally spaced; every via hole connects a top shield plane layer, a first middle layer and a bottom shield plane layer of the magnetic probe; every via hole is placed out of a rectangle gap at the bottom of the magnetic probe; the via holes form a fence. The construction method: 1. constructing a simulation model formed by the magnetic probe and a 50Ω microstrip in a CST® microwave studio; 2. simulation setting; 3. placing via holes along two sides of the central conductor; 4. connecting a 50Ω matching load to the second end of the microstrip and defining the first end as microstrip port1; defining the end on which mount a SMA connector as probe port2; simulating S21.