Transparent Antenna Structure Using a Slot Gap to Cut ITO Loss
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Solution Overview
Problem
The large resistance value of indium tin oxide (ITO) films in transparent antennas leads to significant current loss and decreased radiation efficiency.
Innovation Solution
An antenna device design featuring a metal housing with an open surface, a display circuit, a first transparent conductor plate, a second transparent conductor plate spaced apart to create a gap, and a feeder between the metal housing and the second transparent conductor plate, with a specific area ratio between the plates to improve radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent antenna is used with an ITO film, then the antenna achieves transparency and display functionality, but the radiation efficiency decreases due to large resistance and current loss
Solution Approach 1:
The antenna is divided into two separate transparent conductor plates (first and second plates) with a gap between them. This segmentation isolates the radiating element (second plate) from the display circuit substrate (first plate with ITO film), preventing current loss in the ITO film while maintaining transparency. The gap between the plates creates a slot antenna structure that enables efficient radiation.
Solution Approach 2:
A feeder is introduced as an intermediary component between the metal housing and the second transparent conductor plate. The feeder provides a low-resistance current path to the radiating element without requiring current flow through the high-resistance ITO film, thus improving radiation efficiency while maintaining the transparent antenna structure.
2Ease of operation
If current flows through the ITO film for antenna operation, then the antenna functions, but significant current loss occurs due to large resistance
Solution Approach 1:
The current path is extracted from the ITO film by introducing a dedicated feeder that connects the metal housing directly to the second transparent conductor plate. This separates the display circuit function (through ITO film) from the antenna radiation function, allowing the antenna to operate without significant current loss in the high-resistance ITO film.
Solution Approach 2:
The feeder acts as an intermediary that provides an alternative current path, bypassing the high-resistance ITO film. This mediator component enables efficient current delivery to the radiating element while the ITO film continues to serve its display circuit function without bearing the antenna operating current.
3Loss of energy
If the second transparent conductor plate area is increased to improve radiation, then the directivity gain improves, but the area ratio constraint must be maintained
Solution Approach 1:
The patent specifies a particular area ratio range (0.6 or more to 1.1 or less) between the second transparent conductor plate and the first transparent conductor plate. This parameter optimization allows the radiating element to achieve sufficient directivity gain while maintaining proper coupling with the display circuit and avoiding excessive size that would complicate the device structure.
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 the radiation efficiency and directivity gain of the main polarized wave by reducing current flow through the ITO film and utilizing the gap as a slot antenna for magnetic field radiation.
Implementation Method 1
utilizing the gap as a slot antenna for magnetic field radiation
Implementation Method 2
a feeder provided between the metal housing and the second transparent conductor plate
Data Source
AI summary
An antenna device includes; a metal housing in which at least one surface thereof is open; a display unit provided inside the metal housing and configured to perform a display from the one surface of the metal housing toward outside; a first transparent conductor plate present in the display unit; a second transparent conductor plate provided to be spaced apart from the first transparent conductor plate in an outside or inside direction, the second transparent conductor plate to define a gap between the second transparent conductor plate and the metal housing; and a feed unit provided between the metal housing and the second transparent conductor plate.