Antenna Feed Line Layout for Stable 76-81 GHz Radiation Patterns
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Solution Overview
Problem
Existing antenna devices struggle to maintain low loss and high radiation efficiency while achieving consistent radiation patterns over a wide bandwidth, particularly in frequency bands ranging from 76 GHz to 81 GHz, which is crucial for detecting objects over medium to long distances in vehicles.
Innovation Solution
The antenna device incorporates a feed line with varying widths and a configuration of antenna elements connected at predetermined intervals, featuring alternating connection portions and intermediate portions with narrower widths to reduce destructive interference, ensuring consistent radiation patterns across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional feed line with uniform width is used, then the structure is simple and easy to manufacture, but the radiation pattern becomes inconsistent and gain variations increase over wide bandwidth
Solution Approach 1:
The feed line is designed with varying widths where different sections have different dimensions. Specifically, the feed line includes a first section with width W1, a second section with width W2, and a third section with width W3, where W1 > W2 and W3 > W2. This local variation in geometric properties optimizes the impedance matching and current distribution at different locations, resulting in consistent radiation patterns and reduced gain variations across the 76-81 GHz bandwidth.
2Area of stationary object
If antenna elements are spaced closely to reduce device size, then the device complexity is reduced, but destructive interference increases and radiation efficiency decreases
Solution Approach 1:
A ground structure is introduced as an intermediary element between the antenna elements. The ground structure includes a first ground element and a second ground element positioned between the first and second antenna elements, respectively. This intermediary ground structure acts as a shield to reduce mutual coupling and destructive interference between closely spaced antenna elements, thereby maintaining high radiation efficiency while enabling compact device size.
3Power
If the feed line width is increased to improve power transmission, then the power transmission capability is enhanced, but the frequency-dependent gain variations increase
Solution Approach 1:
The feed line geometry parameters are optimized by varying the width across different sections. The feed line transitions from a wider first section (W1) to a narrower second section (W2), and then to a wider third section (W3), creating an impedance transformation profile that compensates for frequency-dependent effects. This parameter optimization ensures consistent gain across the 76-81 GHz frequency band while maintaining effective power transmission to the antenna elements.
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 results in an antenna device that maintains consistent radiation patterns and reduces frequency-dependent gain variations, enhancing detection capabilities over a wide bandwidth.
Implementation Method 1
a feed line extending in a first direction on one surface of a substrate, a first antenna element connected to the feed line in a second direction, substantially perpendicular to the first direction... configured to transmit the RF signal of a predetermined frequency band through the first antenna element and the second antenna element by feeding power to one end of the feed line
Implementation Method 2
an antenna device operating in a frequency band ranging from approximately 76 GHz to 81 GHz may be mounted on a vehicle to detect objects over medium to long distances from the vehicle
Data Source
AI summary
An antenna device includes a feed line extending in a first direction on one surface of a substrate, a first antenna element connected to the feed line in a second direction, substantially perpendicular to the first direction, a second antenna element connected to the feed line, spaced apart from the first antenna element at a predetermined interval, and extending in a third direction opposite to the second direction, and a communication circuit for transmitting a radio-frequency (RF) signal of a predetermined frequency band through the first and second antenna elements by feeding power to one end of the feed line. The feed line may include first and second connection portions connected to the first and second antenna elements, respectively, and a first intermediate portion between the first and second connection portions. The first intermediate portion may have a width smaller than that of the first or second connection portion.