EBG Structure Member Suppressing Harmonic Noise in Wireless Devices
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Solution Overview
Problem
Conventional methods to reduce unnecessary radiation noise from wireless communication apparatuses often decrease antenna radiation gain, as they either absorb electromagnetic waves or electrically connect the antenna's GND to the housing, leading to resonance suppression issues.
Innovation Solution
A polyhedral EBG structure member is placed between the dielectric substrate and the conductive housing, acting as a harmonic current pass and suppression member, which allows harmonic current components to flow onto the conductive cover while maintaining the antenna's radiation gain by preventing resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a radio wave absorber is bonded to the dielectric substrate to absorb electromagnetic waves, then unnecessary radiation noise is reduced, but antenna radiation gain decreases
Solution Approach 1:
The conductive member is divided into two distinct parts: a first conductive portion that contacts the dielectric substrate and a second conductive portion that contacts the conductive housing. This segmentation allows different portions to perform different functions - one for maintaining antenna performance and the other for suppressing radiation noise, thereby resolving the contradiction between reducing noise and maintaining gain
Solution Approach 2:
The EBG structure is introduced as an intermediary component between the dielectric substrate and the conductive housing. This EBG structure acts as a mediator that selectively suppresses unnecessary radiation noise while allowing the antenna to maintain its radiation gain, thus resolving the contradiction by providing a intermediate solution that balances both requirements
2Object-generated harmful factors
If the GND portion is electrically connected to the conductive housing to suppress resonance, then unnecessary radiation is reduced, but antenna radiation gain decreases
Solution Approach 1:
The conductive member is designed with non-uniform properties: the first conductive portion has different characteristics than the second conductive portion. Specifically, the EBG structure is applied to the portion contacting the housing to provide resonance suppression, while the portion contacting the dielectric substrate maintains optimal electrical connection for antenna performance. This local differentiation allows simultaneous achievement of both goals
Solution Approach 2:
The conductive member combines different conductive structures - a conventional conductive portion for electrical connection and an EBG structure portion for resonance suppression. This composite approach allows the single component to fulfill both functions: maintaining antenna gain through proper electrical connection while reducing unnecessary radiation through EBG resonance suppression
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
This solution effectively reduces harmonic noise without decreasing the antenna's radiation gain by suppressing unwanted radiation currents while maintaining optimal antenna mounting conditions.
Implementation Method 1
an EBG (Electromagnetic Band Gap) structure which prevents the propagation of electromagnetic waves in a specific frequency band
Implementation Method 2
a technique of bonding a radio wave absorber that absorbs electromagnetic waves to an electrical component or transmission path which emits unnecessary electromagnetic waves
Implementation Method 3
the structure member is provided between the dielectric substrate and the conductive housing, and the suppression member is disposed along a current path of a harmonic current component flowing in the pass member
Data Source
AI summary
A structure member is mounted in a communication apparatus including a conductive housing incorporating a dielectric substrate on which a high-frequency circuit is mounted. The structure member includes a pass member which passes a harmonic current component of an operating frequency generated in the dielectric substrate when the high-frequency circuit operates, and a suppression member having an EBG structure which suppresses a predetermined current component of the operating frequency. The structure member is provided between the dielectric substrate and the conductive housing. The suppression member is disposed along a current path of a harmonic current component flowing in the pass member.