Antenna Tilt Drive Using Shape Memory Alloy
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Solution Overview
Problem
Existing antenna systems with remote electrical tilt drives are complex, large, and heavy due to the use of DC motors and gearboxes, leading to increased wind loads, weight, and costs, while also generating passive intermodulation and having limited lifetime in harsh outdoor environments.
Innovation Solution
A remote electrical tilt drive using a shape memory alloy arrangement that moves the phase shifter linkage without the need for motors or gearboxes, allowing for a slim and reliable configuration, with energy applied through electrical current or heat, and optionally using a counter motion member and locking device for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC motors and gear boxes are used in the remote electrical tilt drive, then the antenna can achieve phase shifting through mechanical movement, but the structure becomes complex and the size increases
Solution Approach 1:
The patent replaces the traditional mechanical system (DC motors and gear boxes) with an electrical system. The remote electrical tilt drive uses an electrically controllable phase shifter that directly adjusts the phase of signals without requiring mechanical movement of the antenna. This substitution eliminates motors, gear boxes, and mechanical linkages, thereby resolving the contradiction between achieving phase shifting capability and maintaining structural simplicity.
2Reliability
If DC motors and gear boxes are used in the remote electrical tilt drive, then the antenna can achieve phase shifting through mechanical movement, but the weight increases
Solution Approach 1:
The patent replaces the heavy mechanical components (DC motors and gear boxes) with a lightweight electrical phase shifting system. The electrically controllable phase shifter uses electronic circuits to adjust signal phase without requiring physical movement, thereby significantly reducing the weight of the antenna while maintaining the phase shifting capability.
3Reliability
If DC motors and gear boxes are used in the remote electrical tilt drive, then the antenna can achieve phase shifting through mechanical movement, but the wind load increases
Solution Approach 1:
The patent eliminates the mechanical movement components (motors, gear boxes, and movable linkages) that increase the physical profile and surface area of the antenna. By using an electrical phase shifting system, the antenna maintains a streamlined structure with reduced surface area, thereby minimizing wind load while preserving the phase shifting capability through electronic control.
4Reliability
If DC motors are used inside the antenna housing, then the antenna can achieve mechanical tilting, but passive intermodulation is generated requiring sophisticated shielding
Solution Approach 1:
The patent replaces the mechanical tilting system with an electrical phase shifting system. Instead of using DC motors that generate passive intermodulation and require sophisticated shielding, the invention uses electronic phase shifters that control the phase of signals electrically. This substitution eliminates the harmful electromagnetic interference from motors while achieving the same functional goal of beam tilting through phase adjustment.
5Ease of operation
If DC motors and electronics are used in harsh outdoor environments, then the antenna can achieve remote control, but the lifetime is limited
Solution Approach 1:
The patent replaces the mechanical system with DC motors and gear boxes with an electrical phase shifting system. The electrically controllable phase shifter has no moving parts, eliminating mechanical wear and tear that limits the lifetime of motors in harsh outdoor environments. This substitution maintains remote control capability while significantly extending the operational lifetime by eliminating components susceptible to mechanical degradation.
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 simplifies the antenna structure, reduces weight and wind loads, enhances reliability, and extends the lifetime of the antenna by eliminating the need for motors and complex electronics, while maintaining precise control over signal phase shifting.
Implementation Method 1
a shape memory alloy arrangement configured to move the movable phase shifter linkage (e.g. of a phase shifter of the antenna) in a predetermined direction upon energy being supplied to the shape memory alloy arrangement
Implementation Method 2
The applying of energy to the shape memory alloy arrangement can for example be performed by supplying an electrical current to the shape memory alloy arrangement
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
An antenna (1) including a remote electrical tilt drive (2) for driving a movable phase shifter linkage (4) is provided. The remote electrical tilt drive (2) comprises a shape memory alloy arrangement (5) attached to a non-moving part (6) of the antenna (1) and to the movable phase shifter linkage (4), wherein the shape memory alloy arrangement (5) is configured to move the movable phase shifter linkage (4) in a predetermined direction upon an electrical current being supplied to the shape memory alloy arrangement, and a counter motion member (7) attached to the non-moving part (6) of the antenna (1) and to the movable phase shifter linkage (4) and configured to move the movable phase shifter linkage (4) in a direction opposite to the predetermined direction.