Vehicle Window Antenna Coupling Loss Reduction
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Solution Overview
Problem
Conventional antennas experience significant coupling loss when receiving AM broadcasting signals, leading to insufficient receiving sensitivity due to the large capacitance coupling between internal and external electrodes.
Innovation Solution
The design incorporates a dielectric layer between the glass plates with strategically positioned electrodes and an antenna element, ensuring a coupling capacitance that satisfies the formula Cc ≥ Ci × Ca × vxdB / (va × (Ca + Ci)), where x is 3.0 or less, to minimize coupling loss and enhance receiving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If capacitance coupling is used to extract signal from antenna element, then signal extraction is achieved, but coupling loss is large and receiving sensitivity is insufficient
Solution Approach 1:
The patent changes the electrical parameters of the coupling system by introducing a transformer with specific turns ratio (N1:N2) and optimizing the coupling capacitance value. By adjusting these parameters, the coupling loss is reduced to 3.0 dB or less while maintaining adequate signal extraction, thereby resolving the contradiction between energy loss and receiving sensitivity.
2Device complexity
If internal electrode and external electrode are arranged close to each other for compact design, then device complexity is reduced, but coupling capacitance becomes large causing signal loss
Solution Approach 1:
The patent introduces a dielectric member as an intermediary between the internal electrode and external electrode. This dielectric member has optimized dielectric constant and thickness to control the coupling capacitance value, allowing compact electrode arrangement while preventing excessive coupling loss. The dielectric acts as a mediator that enables close positioning without suffering from the harmful effect of large coupling capacitance.
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 achieves sufficient receiving sensitivity for AM broadcasting signals by optimizing the coupling capacitance, reducing the coupling loss to 3.0 dB or less, thereby improving the antenna's performance.
Implementation Method 1
an antenna element arranged between the glass plate and the first surface of the dielectric, and connected to the first electrode, the antenna element receiving at least an electromagnetic wave in a frequency band of amplitude modulation (AM) broadcasting
Implementation Method 2
a second electrode arranged on a second surface side of the dielectric such that the dielectric is interposed between the first electrode and the second electrode... extracting a signal obtained by receiving an electromagnetic wave in the frequency band of the AM broadcasting via a capacitance coupling
Data Source
AI summary
A window glass for a vehicle includes a glass plate; a dielectric having a first surface on a side facing the glass plate, and a second surface; a first electrode arranged between the glass plate and the first surface; a second electrode arranged on the second surface side such that the dielectric is interposed between the first and second electrodes; and an antenna element arranged between the glass plate and the first surface, and connected to the first electrode, the antenna element receiving at least an electromagnetic wave in a frequency band of AM broadcasting, and a coupling capacitance between the first and second electrodes satisfying a condition determined by an antenna capacitance of the antenna element, an input capacitance of an amplifier connected to the second electrode, a voltage value output from the second electrode, and a reception voltage value of the antenna element.