Bluetooth Earphone Antenna Layout for Head-Facing Null Radiation
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Solution Overview
Problem
Bluetooth earphones experience reduced antenna efficiency and performance due to radiation absorption by the user's head, as the antenna's radiation field has a strong radiation point that faces the head, rather than a zero radiation point, when worn.
Innovation Solution
The Bluetooth earphone design features an antenna that extends from the earphone handle portion to the top section, with a flexible circuit board forming currents that combine to create an equivalent current with a zero radiation point facing the user's head, reducing the adverse effect of the head on antenna performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the antenna is placed in the earphone handle portion, then the antenna can be integrated into the device structure, but the radiation field has a strong radiation point facing the user's head which absorbs radiation and reduces antenna efficiency
Solution Approach 1:
The patent changes the electrical length parameters of the antenna and flexible circuit board to create a specific current distribution pattern. By setting the antenna electrical length to 1/4 wavelength and the flexible circuit board electrical length to 1/4 wavelength, the combined equivalent current achieves 1/2 wavelength resonance, positioning the zero radiation point toward the user's head to reduce radiation absorption.
Solution Approach 2:
Instead of accepting the conventional antenna radiation pattern with strong radiation toward the front, the patent inverts the radiation pattern orientation by carefully designing the current path and length. The zero radiation point is positioned to face the user's head, effectively inverting the harmful radiation direction to a safe direction.
2Reliability
If the antenna extends from the connecting section to the top section, then the zero radiation point can face the user's head, but the device structure becomes more complex
Solution Approach 1:
The patent merges the antenna structure with the flexible circuit board into a single integrated current path. The flexible circuit board serves dual purposes: as a structural support and as part of the antenna system. This combination reduces the need for separate antenna components and simplifies the overall device structure while achieving the desired radiation pattern.
Solution Approach 2:
The flexible circuit board is designed to serve multiple functions: providing structural support for the antenna, establishing the current path for radiation, and contributing to the overall device assembly. This multi-functionality reduces the number of separate components needed, thereby reducing device 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
This design significantly improves antenna efficiency and performance by ensuring the zero radiation point faces the user's head, maintaining high efficiency even when worn, with the antenna signal being effectively radiated and sound reception quality enhanced.
Implementation Method 1
The first current and the second current can be combined into an equivalent current in a resonant mode. The antenna is a 1⁄4 wavelength antenna... An electrical length of the first current is a 1⁄4, an electrical length of the second current is a 1⁄4, an electrical length of the equivalent current obtained by combining the first current and the second current is a 1⁄2 wavelength, and the equivalent current is in the resonant mode
Data Source
AI summary
A Bluetooth earphone includes an earbud portion and an earphone handle portion. A receiver module is disposed in the earbud portion. The earphone handle portion includes a connecting section connected to the earbud portion, and a top section and a bottom section located on both sides of the connecting section, a battery is disposed in the bottom section of the earphone handle portion. The Bluetooth earphone includes an antenna and a flexible circuit board. The antenna extends from the connecting section of the earphone handle portion to the top section of the earphone handle portion. The flexible circuit board includes a feeding part and a first extension part connected to the feeding part. The feeding part is located in the connecting section of the earphone handle portion, and is coupled to the antenna. The first extension part extends to the earbud portion.