Helix Antenna Impedance Transformer With Adjustable Coupling Gap
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Solution Overview
Problem
Conventional helical antennas face impedance mismatch issues between their impedance (120-150 Ohms) and the typical 50 Ohm impedance of RF transmission lines, leading to decibel loss, and existing solutions like modifying the conductive helical tubing or adding a matching circuit board increase complexity and cost.
Innovation Solution
An impedance transformer is integrated with the ground plane structure, featuring protruding conductive structures that adjust their position relative to the helical antenna to match impedance by maintaining a constant gap, allowing impedance transformation without altering the helical antenna or adding circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional helical antenna structures are used, then the antenna can operate in axial mode with directive beam, but impedance mismatch occurs between the antenna (120-150 Ohms) and transmission line (50 Ohms) causing decibel loss
Solution Approach 1:
An impedance transformer comprising multiple conductive structures is introduced as an intermediary element between the helical antenna and the ground plane. These conductive structures protrude toward the helical antenna at adjusted distances, creating capacitive coupling that transforms the antenna impedance to match the 50 Ohm transmission line impedance, thereby eliminating impedance mismatch and reducing decibel loss without modifying the helical antenna itself
2Reliability
If the helical antenna is modified to solve impedance mismatch, then impedance matching may be improved, but the complexity and cost of the antenna structure increases
Solution Approach 1:
The impedance transformation function is segmented from the helical antenna structure and implemented through separate conductive structures on the ground plane. This segmentation allows the helical antenna to maintain its original simple design while the impedance matching function is performed by the additional conductive elements, thus improving impedance matching without increasing the complexity of the antenna itself
Solution Approach 2:
The conductive structures serve as an intermediary impedance transformation layer between the helical antenna and the transmission line. By positioning these structures at specific distances from the helical antenna, impedance matching is achieved through capacitive coupling without requiring any modification to the helical antenna structure, thereby maintaining structural simplicity
3Loss of energy
If a matching circuit board is added to achieve impedance matching, then decibel loss is reduced, but the device complexity and cost increase
Solution Approach 1:
The impedance matching function is extracted from the traditional matching circuit board approach and implemented directly through conductive structures integrated with the ground plane. This extraction eliminates the need for separate matching circuit boards and complex electronic components, reducing device complexity and cost while still achieving the desired impedance transformation and minimizing decibel loss
Solution Approach 2:
The electrical impedance matching function is achieved through geometric configuration of conductive structures rather than through electronic circuitry. By adjusting the physical dimensions and positions of the conductive structures, impedance transformation is accomplished mechanically/geometrically, replacing the need for complex matching circuit boards and electronic components
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 solution effectively matches the helical antenna impedance to the transmission line impedance, reducing decibel loss and maintaining performance across frequency changes, thus enhancing communication efficiency.
Implementation Method 1
The impedance transformer comprises a plurality of conductive structures i) spaced apart from each other, and ii) protruding out and away from the ground plane structure in a direction towards a helical antenna of the antenna element; adjusting a size of a gap provided between the at least one conductive structure of the impedance transformer and the helical antenna until an impedance of the helical antenna matches an impedance of a transmission line
Data Source
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AI summary
Systems and methods for improving operations of an antenna element. The methods comprise: coupling an impedance transformer to a ground plane structure of the antenna element (wherein the impedance transformer comprises at least one conductive structure protruding out and away from the ground plane structure in a direction towards a helical structure of the antenna element); adjusting a size of a gap provided between the at least one conductive structure of the impedance transformer and the helical structure until an impedance of the helical antenna matches an impedance of a transmission line at one or more frequencies; and securing the impedance transformer to the ground plane structure so that the size of the gap is maintained while the antenna element is being used to facilitate communications.