Transparent Window Antenna Structure for Low-Loss Broadband Transmission
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Solution Overview
Problem
Existing railway vehicles face challenges in maintaining broadband wireless communication due to high signal attenuation through metallic structures and the limitations of active repeater systems, which require frequent upgrades and licensing, and existing window treatments are ineffective for large angles of incidence.
Innovation Solution
Implementing an optical construction with slot-fed patch antennas on vehicle windows that allow selective transmission of certain frequency bands, utilizing electrically conductive layers with through openings aligned with antennas to maintain high transmission coefficients across various angles and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic structures are used in railway vehicles, then structural strength and shielding are improved, but signal attenuation increases
Solution Approach 1:
The continuous metallic window treatment is segmented into an array of discrete patch antennas with gaps between them. This segmentation allows the window to maintain structural metallic properties while creating transmission paths for electromagnetic signals through the gaps, reducing signal attenuation while preserving structural strength.
Solution Approach 2:
The window treatment has different local properties: the patch antennas provide shielding and structural integrity in most areas, while the gaps between patches provide signal transmission paths. This local differentiation allows simultaneous achievement of structural strength and reduced signal attenuation.
2Reliability
If active repeater systems are deployed, then broadband wireless communication is enabled, but device complexity and operational requirements increase
Solution Approach 1:
The window treatment itself provides the signal transmission function without requiring external active repeater systems. The passive antenna structure enables broadband wireless communication by allowing signals to pass through the vehicle window, eliminating the need for complex active electronic systems inside the vehicle.
3Object-generated harmful factors
If conventional window treatments are applied, then electromagnetic shielding is improved, but transmission coefficient deteriorates at large angles of incidence
Solution Approach 1:
The antenna geometry and spacing are designed to maintain effective signal transmission across a wide range of incident angles. The patch antenna configuration and gap dimensions are optimized so that the transmission coefficient remains relatively stable from normal incidence to oblique angles, dynamically adapting to different signal arrival directions.
4Loss of energy
If electrically conductive layers with through openings are used, then signal transmission is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patch antennas and gaps are formed as an integrated structure in a single manufacturing process, eliminating the need for separate alignment steps. The conductive layers are patterned to create both the shielding patches and the transmission gaps simultaneously, reducing manufacturing precision requirements compared to assembling separate components.
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
Enhances signal transmission through vehicle windows with minimal attenuation, supporting broadband communication across a wide range of angles and frequencies without the need for active repeaters or additional infrastructure.
Implementation Method 1
The corresponding first and second coupling elements are electromagnetically coupled to each other so that for a first incident signal incident on the optical construction in a first incident plane and having a first polarization state, plots of a transmission coefficient S21 of the optical construction versus frequency
Implementation Method 2
one or more metal layers disposed between, and at least substantially co-extensive in length and width with, the pluralities of the first and second antennas. Each of the one or more metal layers define a plurality of through openings therein
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
An optical construction includes optical stacks arranged across the construction and spaced apart from each other. Each of the optical stacks has a transmittance of at least 60% for at least one visible wavelength and includes one or more electrically conductive layers. The optical stacks are coextensive with first and second antennas. Each of the electrically conductive layers defines a through opening aligned with at least one of the first and second antennas. For each of an s-polarized first incident signal incident on the optical construction in a first incident plane and a p-polarized second incident signal incident on the optical construction in a second incident plane orthogonal to the first incident plane, for at least one frequency in a range from 0.5 GHz to 10 GHz, and for incident angles of up to 40 degrees, the optical construction has a transmission coefficient of between 0 dB and -10 dB.