Mobile Terminal Antenna Radiation Preventer Design
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Solution Overview
Problem
Mobile terminals emit high levels of electromagnetic radiation towards the human body, posing health risks, and existing solutions like directional antennas and choke-type baluns are either ineffective or difficult to implement, especially in maintaining antenna separation during design.
Innovation Solution
A mobile terminal antenna design featuring a radiator, ground, and radiation preventer with metallic bars or conductive paint strips arranged along the electric field, which blocks electromagnetic wave radiation by altering the electric field distribution and reducing fringing fields, thereby minimizing radiation towards the human body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the antenna is kept away from the printed circuit board to maximize distance from the human body, then electromagnetic radiation towards the body is reduced, but the printed circuit board still generates electromagnetic waves due to current flow
Solution Approach 1:
A choke-type balun is introduced as an intermediary component between the antenna and the printed circuit board. This balun serves as a mediator that blocks the flow of electric current from the antenna to the printed circuit board, preventing the PCB from acting as a secondary antenna while maintaining proper power feed and signal transmission to the antenna.
Solution Approach 2:
The solution applies a localized electromagnetic shielding approach by placing the choke-type balun specifically at the connection point between the antenna and the printed circuit board. This localized intervention blocks current flow in the critical path without affecting the overall antenna performance or requiring changes to the entire circuit board design.
2Object-generated harmful factors
If a choke-type balun is installed to block current flow from antenna to printed circuit board, then electromagnetic waves from the PCB are reduced, but the antenna separation from the mobile terminal becomes excessive
Solution Approach 1:
The design parameters of the choke-type balun are optimized to achieve the desired current blocking function within a compact form factor. By adjusting the inductance value, physical dimensions, and winding configuration of the balun, the solution achieves effective current blocking while maintaining a small size that does not cause excessive antenna separation from the mobile terminal body.
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 effectively reduces electromagnetic radiation towards the human body while enhancing antenna performance by increasing gain and directivity, as demonstrated by improved radiation patterns and measured gain improvements.
Implementation Method 1
a radiation preventer which has a metallic bar disposed on one side of the ground in parallel thereto and being spatially separated from the ground
Implementation Method 2
blocks electromagnetic wave radiation by altering the electric field distribution and reducing fringing fields
Data Source
AI summary
A mobile terminal and a mobile terminal antenna reduce the intensity of electromagnetic waves radiated in the direction of a human body. The mobile terminal antenna includes a radiator, which radiates electromagnetic waves; a ground which is connected with the radiator, and a radiation preventer which has a metallic bar on one side of the ground in parallel with the ground at an interval. Accordingly, the electromagnetic radiation exposure to the human body can be reduced by altering the radiation emission pattern, while the performance of the antenna can be simultaneously enhanced.