Wireless Earphone Antenna Coupling Capacitor Design
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Solution Overview
Problem
Existing wireless earphones face limitations in antenna operation bandwidth and radiation efficiency due to small antenna dimensions and ground plane constraints, leading to signal attenuation and unstable connections with electronic devices.
Innovation Solution
A wireless earphone design that combines a flexible circuit board with rigid circuit boards to form a coupling capacitor, improving antenna operation bandwidth and radiation efficiency by compensating for the inductive effects of the flexible circuit board, thereby enhancing wireless transmission quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna dimension and ground plane are made small to reduce device size, then the wireless earphone achieves light weight and compact form, but the antenna radiation efficiency and operation bandwidth deteriorate
Solution Approach 1:
The patent changes the electrical parameters of the circuit board by forming a coupling capacitor between the flexible circuit board and rigid circuit board. This capacitor modifies the impedance and resonance characteristics of the antenna system, enabling the small antenna to achieve acceptable radiation efficiency and bandwidth performance despite its compact dimensions.
Solution Approach 2:
The coupling capacitor acts as an intermediary element between the flexible circuit board and rigid circuit board. It mediates the electrical connection while providing capacitive coupling that compensates for the limitations of the small antenna structure, thereby improving overall antenna performance without increasing device size.
2Device complexity
If the flexible circuit board is used to connect rigid circuit boards, then the device achieves compact layout and flexibility, but the inductive effect of the electronic wire distribution causes signal attenuation
Solution Approach 1:
The patent converts the harmful inductive effect of the flexible circuit board into a beneficial capacitive effect. By forming a coupling capacitor using the flexible circuit board and rigid circuit board, the previously harmful inductance is transformed into useful capacitance that improves antenna performance and reduces signal attenuation.
Solution Approach 2:
The patent changes the electrical parameter characteristics of the flexible circuit board connection by creating a capacitive coupling structure. This transforms the electrical behavior from predominantly inductive to predominantly capacitive, thereby reducing signal attenuation and improving wireless transmission quality.
3Area of stationary object
If the antenna ground plane is made small to fit within the device, then the device maintains compact form factor, but the operation bandwidth and radiation efficiency of the antenna are reduced
Solution Approach 1:
The patent changes the electrical parameters of the antenna system by introducing a coupling capacitor. This capacitor modifies the resonant frequency and impedance matching characteristics, enabling the small ground plane to support adequate operation bandwidth and radiation efficiency despite its limited area.
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 design achieves improved antenna radiation efficiency and stable wireless transmission quality by forming a coupling capacitor between the flexible and rigid circuit boards, reducing signal attenuation and ensuring reliable connections with external devices.
Implementation Method 1
A coupling capacitor is formed at a parallel overlapping area between the second connection part and the rigid circuit board
Implementation Method 2
The coupling capacitor is configured to compensate an inductive effect of an electronic pattern of the flexible circuit board
Data Source
AI summary
A wireless earphone including a top cover, a bottom cover, two rigid circuit boards, a flexible circuit board, and an antenna is provided. The bottom cover is connected to the top cover, and an inner chamber is formed between the top cover and the bottom cover. The two rigid circuit boards are disposed at intervals in the inner chamber. The flexible circuit board has a first connection part and a second connection part. Two ends of the first connection part are coupled to the two rigid circuit boards respectively. The second connection part is attached on at least one of the two rigid circuit boards. The antenna is coupled to a corresponding rigid circuit board to radiate a radio frequency signal. A coupling capacitor is formed at a parallel overlapping area between the second connection part and the rigid circuit board.