Capacitively Coupled Patch Antenna for GNSS
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Solution Overview
Problem
Existing patch antennas are inadequate for receiving multiple constellation GNSS signals due to their limited bandwidth and inability to reject cross-polarized signals effectively, which results in reduced positioning accuracy and increased noise interference.
Innovation Solution
A patch antenna configuration with capacitively coupled feed pins that provide electrical isolation and a controlled impedance, allowing for the combination of signals in phase quadrature to achieve a circularly polarized response without the need for large combining networks, enabling improved rejection of cross-polarized signals and enhanced multi-constellation reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional directly-connected feed pins are used, then the antenna structure is simple, but the bandwidth is limited and cross-polarized signal rejection is poor
Solution Approach 1:
The patent introduces an intermediary capacitive coupling structure between the feed pin and the resonant patch. The feed pin does not directly contact the patch but couples through a capacitor formed by the proximity of the feed pin to the patch edge. This intermediary coupling mechanism enables broader bandwidth operation and improved cross-polarization rejection while maintaining structural simplicity.
2Ease of operation
If dual feed pins with direct connection are used, then circular polarization can be achieved, but the combining network becomes large and complex
Solution Approach 1:
The patent merges the feed pin function with the capacitive coupling function. The two feed pins are capacitively coupled to orthogonal edges of the resonant patch, and the capacitive coupling structures themselves provide the signal combining function. This integration eliminates the need for separate large combining networks while achieving circular polarization capability.
3Reliability
If feed pins are physically connected to the resonant plate, then electrical connection is simple, but electrical isolation and controlled impedance are difficult to achieve
Solution Approach 1:
The patent uses capacitive coupling as an intermediary mechanism between the feed pin and the resonant patch. The feed pin is positioned near the patch edge but does not physically contact it, creating a capacitor. This provides natural electrical isolation while maintaining controlled impedance through the capacitive reactance, which can be tuned by adjusting the feed pin position and geometry.
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 capacitively coupled patch antenna design enhances signal rejection and noise matching, improving positioning accuracy and reducing interference, making it suitable for multiple constellation GNSS signals while minimizing additional component costs and complexity.
Implementation Method 1
The feed pins are capacitively coupled to the resonant metal plate to provide an electronic connection between other circuitry and the patch antenna
Data Source
AI summary
Systems and methods relating to patch antennas. A patch antenna has a substrate, a resonant metal plate at one side of the substrate, and a ground plane at the other opposite side of the substrate. Two feed pins are used to couple the antenna to other circuitry. The feed pins pass through the substrate and holes in at the ground plane. The feed pins are physically disconnected from both the resonant metal plate and the ground plane. The feed pins are capacitively coupled to the resonant metal plate to provide an electronic connection between other circuitry and the patch antenna.