Loop Antenna Resonant Frequency Control via Coaxial Cable Segmentation
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Solution Overview
Problem
Existing loop antennas face challenges in controlling resonant frequency without changing the overall length of the antenna element, limiting their ability to operate efficiently across multiple frequency bands while maintaining a small size and high antenna efficiency.
Innovation Solution
Incorporating a coaxial cable at a predetermined section of the antenna element, allowing for the generation of multiple resonant frequencies by opening or shorting the coaxial cable's end, which enables control of resonant frequency without altering the antenna element's length, combined with a power feeding mechanism to supply power to connected antenna elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the antenna is reduced to fit within mobile devices, then the antenna can be internally installed, but the bandwidth is limited and it is difficult to maintain good antenna efficiency
Solution Approach 1:
The antenna element is divided into multiple sections with different electrical lengths. By selectively connecting or disconnecting these sections through switching elements, the antenna can operate at multiple resonant frequencies corresponding to different service bands, thereby achieving wide bandwidth coverage while maintaining a compact overall size.
Solution Approach 2:
The antenna incorporates switching elements that dynamically reconfigure the electrical length of the antenna element. By changing the connection state of the switching elements, the resonant frequency can be adjusted to match different service bands, enabling the antenna to adapt to various frequency requirements without changing its physical size.
2Measurement precision
If the resonant frequency is controlled by changing the length of the antenna element, then the resonant frequency can be adjusted, but the overall length of the antenna element must be changed
Solution Approach 1:
The antenna element is segmented into multiple sections with different electrical lengths. By selectively activating or deactivating specific sections through switching elements, the effective electrical length can be adjusted to control the resonant frequency, without changing the overall physical length of the antenna element.
Solution Approach 2:
Different sections of the antenna element have different electrical lengths and impedance characteristics. By locally controlling the connection state of these sections, the resonant frequency can be precisely adjusted while maintaining a fixed overall antenna length, allowing frequency control without dimensional changes.
3Volume of moving object
If a disk shaped top is installed or the antenna element is twisted to reduce size, then the size can be reduced, but it is difficult to maintain high antenna efficiency
Solution Approach 1:
The antenna uses switching elements to dynamically reconfigure the electrical length and current distribution along the antenna element. This dynamic control allows the antenna to maintain high current at the feed point and optimize radiation efficiency across different frequency bands, even when the physical size is reduced.
Solution Approach 2:
The antenna changes the electrical parameters (length, impedance) of different sections by controlling the switching elements. This allows the antenna to maintain optimal electrical characteristics for high efficiency radiation while keeping the physical dimensions small through proper parameter optimization.
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 allows for a small loop antenna to generate multiple resonant frequencies, achieving high antenna efficiency and ultra-wide bandwidth characteristics, facilitating its installation within mobile devices without compromising size or efficiency.
Implementation Method 1
capable of controlling a resonant frequency without changing an overall length of an antenna element
Data Source
AI summary
Provided is a loop antenna. The loop antenna includes a first antenna element embodied as a coaxial cable, a second antenna element embodied as a line and connected to one end of the first antenna element in series, a third antenna eLement embodied as a line, having one end connected to a ground plane and the other end connected to the other end of the first antenna element in series, and a power feeding cable for supplying power to the second antenna element.