Antenna Device With Segmented Stub For Bandwidth
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Solution Overview
Problem
Conventional patch antennas face challenges in widening bandwidth and improving gain without increasing the overall thickness, which restricts the interval between the antenna surface and ground surface, making it difficult to enhance frequency bandwidth and antenna performance.
Innovation Solution
The antenna device features a three-layer structure with a stub composed of transmission lines of different widths, located between the antenna surface and ground surface, allowing for impedance matching and power feeding, thereby increasing the interval and reducing the Q value, thus widening the bandwidth and improving gain without increasing the device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interval between the antenna surface and ground surface is increased to widen bandwidth and improve gain, then the antenna performance is improved, but the overall thickness of the antenna device increases
Solution Approach 1:
The stub is divided into multiple transmission line segments with different line widths (first, second, and third transmission lines with progressively narrower widths). This segmentation allows each segment to contribute differently to the impedance matching, enabling bandwidth widening and gain improvement without requiring increased overall thickness.
Solution Approach 2:
Different portions of the stub have different line widths tailored to specific functions: wider lines for impedance transformation and narrower lines for resonance control. This local differentiation of properties enables the stub to achieve multiple functions (bandwidth widening and gain improvement) within a compact thickness.
2Reliability
If a conventional stub structure is used for impedance matching, then the antenna can be fed, but the bandwidth is limited and gain is reduced
Solution Approach 1:
The stub is segmented into multiple transmission line sections with different characteristic impedances (different line widths). This segmentation creates a stepped impedance transformer that widens the bandwidth by providing gradual impedance transition, while the series connection maintains relatively simple overall structure.
Solution Approach 2:
The line width parameter is changed across different segments of the stub to create different characteristic impedances. This parameter variation enables the stub to provide both impedance matching and bandwidth widening functions, improving antenna performance without excessive structural complexity.
Data Source
AI summary
The antenna device includes an antenna surface having an antenna conductor, a ground surface facing the antenna surface and having a ground conductor, and a stub including a plurality of transmission lines coupled in series, the plurality of transmission lines having different line widths. The stub is located between the antenna surface and the ground surface. The antenna conductor electrically conducted to the stub via a feeding point coupled to a transmission line on one end side, of the plurality of transmission lines.