Electronic Key Antenna Layout Using Capacitive Housing Coupling
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Solution Overview
Problem
Existing electronic vehicle key antenna arrangements require significant space and are costly due to the need for multiple antennas and matching circuits, which compromises size and performance.
Innovation Solution
An antenna arrangement that includes a printed circuit board with an antenna, a processing unit, and a power source inside the key, and a conductive layer on the outside of the housing for capacitive coupling, allowing for a compact and cost-effective implementation of ultra-wide band signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennas and matching circuits are used in electronic vehicle keys, then communication functionality is improved, but space requirements and manufacturing costs increase
Solution Approach 1:
The patent combines multiple antenna functions into a single UWB antenna structure that integrates both transmitting and receiving capabilities. The antenna is formed as a compact planar structure on the PCB, merging what would traditionally require separate antenna elements into one unified component, thereby reducing space requirements while maintaining communication functionality.
Solution Approach 2:
The UWB antenna is designed to serve multiple communication purposes simultaneously - it can transmit and receive signals across a wide frequency band, enabling both keyless entry and other wireless communication functions. This multi-functional design eliminates the need for separate dedicated antennas for different communication protocols, reducing overall space requirements.
2Adaptability or versatility
If multiple antennas and matching circuits are used in electronic vehicle keys, then communication functionality is improved, but manufacturing costs increase
Solution Approach 1:
The patent integrates the antenna and matching circuit into a single printed circuit board structure, where the antenna trace and matching components are fabricated together using standard PCB manufacturing processes. This integration eliminates the need for separate antenna assemblies and reduces the number of discrete components, thereby lowering manufacturing costs while maintaining full communication functionality.
Solution Approach 2:
The patent replaces traditional mechanical antenna structures (such as wire antennas or separate antenna modules) with a planar printed circuit board antenna. This substitution allows the antenna to be manufactured using standard PCB fabrication techniques rather than requiring separate antenna assembly processes, significantly reducing manufacturing complexity and cost.
3Volume of moving object
If antenna size is reduced for compact key design, then space requirements are reduced, but impedance matching becomes more difficult
Solution Approach 1:
The patent employs impedance matching circuits with variable component values (capacitors and inductors) that can be optimized for different antenna sizes. By adjusting the values of these matching components, the system achieves proper 50-ohm impedance matching even with compact antenna dimensions. The matching circuit parameters are specifically tuned to compensate for the reduced antenna size, maintaining performance without increasing overall 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 configuration enhances antenna performance by matching impedance to 50Ohm, increasing bandwidth and radiation efficiency, particularly for high-frequency transmissions, while minimizing additional components and space requirements.
Implementation Method 1
a conductive layer (210) arranged on the outside of the housing (200) and capacitively coupled to the antenna (208). The conductive layer (210) acts as a capacitance, thereby matching the impedance of the antenna (208) more closely to a desired impedance
Data Source
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AI summary
An antenna arrangement for an electronic key comprises a printed circuit board (202) arranged inside a housing (200) of the electronic key, an antenna (208) arranged on the printed circuit board (202) and inside the housing (200), a processing unit (204) arranged on the printed circuit board (202) and inside the housing (200), and configured to control the antenna (208), a power source (206) arranged on the printed circuit board (202) and inside the housing (200), and configured to provide power to the antenna arrangement, and a conductive layer (210) arranged on the outside of the housing (200) and capacitively coupled to the antenna (208).