Compact-Range Antenna Measurement Using Articulated Robot
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Solution Overview
Problem
Existing antenna radiation measurement methods require large spaces and high costs due to the need for long distances to achieve far-field conditions, especially in millimeter-wave frequency bands, and suffer from instability and measurement errors caused by vibrations during rotation.
Innovation Solution
A movable compact-range antenna measurement system using an articulated robot with a specific geometric surface, such as a dish-shaped reflection surface, lens, or matrix, that allows for short-distance measurements while maintaining accuracy, enabling the antenna to remain stationary and perform multi-angle scans without the need for extensive site setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If far-field measurement distance is increased to meet R=2D2/λ condition, then measurement accuracy is improved, but measurement space and cost are significantly increased
Solution Approach 1:
The patent introduces a geometric surface (such as a parabolic reflector or lens) as an intermediary between the probe and the antenna under test. This geometric surface transforms the spherical wave from the probe into a plane wave, enabling far-field measurement conditions to be achieved at a much shorter distance. The geometric surface acts as a mediator that creates the equivalent of a far-field environment in a compact space.
Solution Approach 2:
The patent changes the measurement distance parameter from the traditional far-field distance (R=2D2/λ) to a compact range distance by using the geometric surface to transform the wave propagation characteristics. This parameter change allows measurements to be performed at distances much shorter than the conventional far-field requirement while maintaining measurement accuracy.
2Adaptability or versatility
If AUT is placed on a rotating base to sweep radiation directions, then multi-angle measurement capability is improved, but positioning stability deteriorates due to vibration
Solution Approach 1:
Instead of rotating the antenna under test (AUT) on a rotating base, the patent inverts the approach by keeping the AUT stationary and rotating the probe assembly. The geometric surface is mounted on the movable end of the articulated robot, allowing the probe to sweep through different angles while the AUT remains fixed. This inversion eliminates the vibration and positioning instability associated with rotating the AUT.
Solution Approach 2:
The patent replaces the traditional mechanical rotating base system with an articulated robot system that uses controlled movement of the probe assembly. The articulated robot provides precise positioning and movement control without the mechanical vibrations inherent in traditional rotating bases, substituting a more advanced mechanical system for the problematic one.
3Adaptability or versatility
If probe feeding mechanism is used to excite AUT, then measurement flexibility is improved, but system reliability deteriorates due to probe breakage from vibration
Solution Approach 1:
The patent inverts the traditional feeding arrangement by placing the geometric surface (such as a parabolic reflector) on the movable end of the articulated robot rather than moving the probe itself. This inversion protects the probe from vibration and mechanical stress while maintaining the ability to sweep through different measurement angles, thereby improving reliability without sacrificing flexibility.
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 reduces measurement costs, enhances stability, and allows for accurate multi-angle data collection in a single site, suitable for millimeter-wave frequency bands, without the need for multiple measurement sites or large spaces.
Implementation Method 1
the specific geometric surface is a dish-shaped reflection surface for reflecting the signal from the feed antenna as the incident signal
Implementation Method 2
the specific geometric surface is a lens element for focusing the signal from the feed antenna as the incident signal
Implementation Method 3
the specific geometric surface is a reflection matrix with M×N reflection units for reflecting the signal from the feed antenna as the incident signal
Implementation Method 4
the specific geometric surface is a transmission matrix with M×N transmission units for focusing the signal from the feed antenna as the incident signal
Data Source
AI summary
An antenna measurement system is configured to measure a radiation field pattern of an AUT fixed on a reference surface. The antenna measurement system includes an articulated robot, a measurement component, and a processor. The articulated robot is seated on a periphery of the reference surface, with a movable end capable of scanning a short-distance area defined by the reference surface. The measurement component is arranged on the movable end of the articulated robot, and a front surface of the measurement component is a specific geometric surface, which is used to face the antenna for radiation measurement. The processor is coupled to the movable end to control the movable end to drive the measurement component to move relative to the antenna along a predefined scanning path, and keep the specific geometric surface facing the antenna during the movement along the scanning path.