Circular Polarized Coupling Device with Asymmetric Feed
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Solution Overview
Problem
Conventional coupling devices for transmitting circular polarized wireless signals have limited axial ratio bandwidth, restricting the transmission of wireless signals with various resonance directions and offering a narrow transmission band.
Innovation Solution
A coupling device with a substrate, ground layer, and feed conductor, featuring a circular opening in the ground layer and a feed portion that varies radially with angle, enhancing axial ratio bandwidth and transmission efficiency by forming a special resonance area for signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional rectangular radiator with fixed lead angle is used, then the device structure is simple, but the axial ratio bandwidth is limited to about 3-5%
Solution Approach 1:
The patent applies asymmetry by transitioning from a conventional rectangular radiator to a circular opening structure with an asymmetric feed conductor configuration. The feed conductor is positioned at a specific radial distance from the center with a determined lead angle, creating an asymmetric current distribution that enables circular polarization. This asymmetric design resolves the contradiction by achieving wide axial ratio bandwidth (35-45%) while maintaining relatively simple device structure.
Solution Approach 2:
The patent employs parameter changes by optimizing specific geometric parameters including the radial distance of the feed conductor from the center, the lead angle of the feed conductor, and the diameter of the circular opening. By carefully selecting these parameters, the invention achieves wide axial ratio bandwidth and improved adaptability for transmitting wireless signals with various resonance directions, while keeping the overall device structure manageable.
2Ease of manufacture
If a conventional coupling device with fixed geometry is used, then the manufacturing is simple, but the transmission band is narrow (return loss lower than -10 dB only in limited range)
Solution Approach 1:
The patent achieves wide transmission band (9-11 GHz with return loss lower than -10 dB) by optimizing key parameters including the radial distance of the feed conductor, the lead angle, and the circular opening dimensions. These parameter adjustments enable the device to maintain good impedance matching and wide bandwidth performance while remaining manufacturable using standard PCB and antenna fabrication techniques.
Solution Approach 2:
The patent transitions from a rectangular radiator to a circular opening structure, applying curvature principles that improve current distribution and reduce edge effects. This circular geometry, combined with the asymmetric feed conductor placement, creates more uniform current flow patterns that enhance bandwidth and transmission performance while maintaining ease of manufacture through standard circular drilling and plating processes.
3Device complexity
If a rectangular radiator with fixed lead angle is used, then the device structure is simple, but the device cannot transmit wireless signals having various resonance directions
Solution Approach 1:
The asymmetric feed conductor configuration within the circular opening creates circularly polarized radiation patterns that are insensitive to the orientation of receiving antennas. This asymmetric design enables the device to transmit wireless signals with various resonance directions effectively, resolving the contradiction between simple structure and enhanced signal transmission capability for multiple directions.
Solution Approach 2:
The circular opening structure with asymmetric feed conductor provides universal transmission capability for wireless signals with various resonance directions. The design functions effectively for both circularly polarized and linearly polarized signals, making the device multi-functional and adaptable to different signal types and transmission scenarios while maintaining a relatively simple overall 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
The solution provides an axial ratio bandwidth of about 15% and a transmission band of 9-11 GHz with return loss lower than -10 dB, enabling the transmission of wireless signals with various resonance directions and expanding the bandwidth significantly.
Implementation Method 1
a length of the radial distance varies with an angle between the radial line and the base line... forming a special resonance area for signal transmission
Data Source
AI summary
A coupling device for transmitting a wireless signal is provided. The coupling device includes a substrate, a ground layer and a feed conductor. The substrate includes a first surface and a second surface opposite to the first surface. The ground layer is disposed on the second surface having a circular opening, and the circular opening has an opening edge and an opening center. The feed conductor extends on the first surface, including a conductive portion and a feed portion connected thereto. The feed portion corresponds to the circular opening, wherein the opening center is on a base line, a radial line is formed between the opening center and the opening edge, a radial distance is formed on the radial line between the opening edge and the feed portion, and a length of the radial distance varies with an angle between the radial line and the base line.