Adjustable Antenna Element With Retractable Conductive Member
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Solution Overview
Problem
Existing radio antenna systems require long physical lengths for lower frequencies, leading to mechanical challenges and performance degradation when using loading coils to shorten elements.
Innovation Solution
An adjustable antenna element with a hollow support arm and length-adjustable conductive member, using a stepper motor to precisely control the length, allowing for reduced overall length and improved mechanical stability, and employing a 180° radial curve to maintain performance across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the frequency of operation is lowered, then the antenna can cover a wider frequency range, but the physical length of the antenna element must increase
Solution Approach 1:
The patent employs adjustable-length antenna elements that can dynamically change their physical length to resonate at different frequencies. The elements are constructed with telescoping or extendable mechanisms allowing the antenna to adapt its length for optimal performance across multiple frequency bands including 40-meter and 80-meter bands, resolving the contradiction between wide frequency coverage and manageable physical length.
Solution Approach 2:
The antenna system divides the element into multiple adjustable segments that can be extended or retracted independently. This segmentation allows the antenna to achieve the necessary resonant lengths for lower frequencies when needed, while maintaining a compact form when operating at higher frequencies, thus addressing both the frequency coverage requirement and the physical length constraint.
2Length of moving object
If loading coils are used to shorten the physical length of antenna elements, then the antenna length is reduced, but the performance of the antenna degrades
Solution Approach 1:
Instead of using static loading coils that degrade performance, the patent implements dynamically adjustable element lengths through telescoping construction. This allows the antenna to achieve proper resonant length for each frequency band without requiring loading coils, thereby maintaining optimal radiation efficiency and performance across all operating frequencies while keeping the physical length manageable.
3Adaptability or versatility
If the element length is increased for lower frequency operation, then the antenna can resonate at lower frequencies, but mechanical stress and wind survivability become more challenging
Solution Approach 1:
The patent employs adjustable-length elements that can be retracted to shorter configurations when not needed for low-frequency operation. This dynamic capability allows the antenna to achieve the necessary resonant length for 40-meter and 80-meter bands only when required, while maintaining a compact, mechanically robust form factor that exhibits superior wind survivability and reduced mechanical stress during normal operation and severe weather conditions.
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 allows for reduced antenna length, improved mechanical stability, and enhanced performance with lower impedance, achieving excellent frequency coverage and gain while maintaining a low voltage-standing-wave-ratio (VSWR).
Implementation Method 1
the conductive member is adjusted by employing two spools located inside the housing unit in which the conductive member is wound. During use, the conductive member is selectively wound and unwound from a spool so that the conductive member moves inside the support arm
Implementation Method 2
At least one motor is provided inside the housing unit that rotates the spool to precisely control the length of the conductive member inside the support arm
Implementation Method 3
as the frequency of operation of the antenna becomes lower, the physical length of the antenna element must increase to allow it to resonate at the selected frequency
Data Source
AI summary
An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. Each conductive member is stored on a spool that is selectively rotated to extend the conductive member into the support arm. The support arms are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency. The antenna can be optimally tuned at a specific frequency for maximum gain, maximum front-to-back ratio, as a bi-directional antenna, and to provide a desired feed point impedance. An electronic control system allows the length of the conductive members to be manually or automatically adjusted to a desired frequency.