Composite Antenna Layout to Prevent Opposed Current Loss
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Solution Overview
Problem
Existing vehicle-mounted film-type composite antennas suffer from deteriorated radiation efficiency due to oppositely-directed currents, particularly when antenna elements and terminals are densely arranged, which affects their performance and power supply.
Innovation Solution
A composite antenna device comprising a dipole antenna element with a ground loop element and a circularly polarized antenna element, where the second hot terminal is sandwiched between the first and ground terminals, and a ground loop element surrounds the circularly polarized antenna elements, preventing oppositely-directed currents and facilitating power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If antenna elements and connection terminals are densely arranged to reduce mounting area, then the mounting area is reduced, but oppositely-directed currents occur between hot terminal and ground terminal causing deterioration in radiation efficiency
Solution Approach 1:
A ground loop element is introduced as an intermediary component between the hot terminal and ground terminal. This ground loop element provides an alternative current path that prevents oppositely-directed currents from occurring directly between the hot and ground terminals, thereby maintaining radiation efficiency while allowing dense arrangement of antenna elements within the constrained mounting area.
Solution Approach 2:
The antenna system is segmented into multiple functional elements including dipole antenna elements, circularly polarized antenna elements, and ground loop elements. Each element is independently configured to perform specific functions, allowing the overall system to achieve both compact size and optimal current distribution patterns that prevent energy loss.
2Area of stationary object
If a loop element is deformed into a convex shape to reduce mounting area, then the mounting area is reduced, but oppositely-directed currents occur between portions facing each other causing deterioration in radiation efficiency
Solution Approach 1:
The ground loop element serves as a mediator that intercepts and redirects currents before they can form oppositely-directed patterns between convex portions of the loop. By providing this intermediate current path, the system maintains both the compact convex geometry and acceptable radiation efficiency.
3Adaptability or versatility
If multiple antenna elements are arranged densely to support more frequency bands, then frequency band coverage is improved, but oppositely-directed currents occur causing deterioration in radiation efficiency
Solution Approach 1:
The ground loop element performs multiple functions simultaneously: it serves as a current path for the dipole antenna elements, provides grounding for the circularly polarized antenna elements, and prevents oppositely-directed currents across the entire multi-frequency system. This universal component enables dense arrangement of multiple frequency-supporting elements without energy loss.
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 prevents deterioration in radiation efficiency, enhances antenna characteristics, and facilitates power supply, allowing for miniaturization and cost reduction while supporting multiple frequency bands.
Implementation Method 1
a ground loop element that extends from the ground terminal, passes between the first hot terminal and the second hot terminal, then extends so as to surround the second hot terminal, the third element, and the fourth element, and returns back to the ground terminal
Implementation Method 2
The dipole antenna element may have a parasitic element disposed so as to be capacitively coupled to vicinities of leading ends of the first element and the second element
Data Source
AI summary
A composite antenna includes a dipole antenna element and a circularly polarized antenna element. The dipole antenna element includes a first hot terminal, a ground terminal, a first element extending from the first hot terminal, and a second element extending from the ground terminal. The circularly polarized antenna element includes a second hot terminal disposed on a line connecting the first hot terminal and the ground terminal so as to be sandwiched therebetween, a third element extending from the second hot terminal, and a fourth element extending from the ground terminal perpendicularly with respect to the third element.