Antenna Measurement System Using Symmetric Probe Array
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Solution Overview
Problem
Existing antenna measurement systems face challenges in accurately measuring phase differences of electromagnetic waves from active antennas with integrated RF circuits, particularly due to asymmetric phase directivity and production errors, which affect far-field directivity calculations, especially at high angles and with narrow frequency bands.
Innovation Solution
An antenna measurement system employing multiple probe antennas arranged symmetrically in a measurement plane, with a probe scanning mechanism to measure phase differences between adjacent positions, using standard square waveguide tubes for wideband sensitivity and accuracy, and calculating phase differences to average out asymmetric effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single probe antenna is used for near field measurement, then the measurement setup is simple, but the measurement precision of phase difference is degraded due to asymmetric phase directivity and production errors
Solution Approach 1:
The single probe antenna is segmented into multiple probe antennas (first, second, and third probe antennas) arranged in specific geometric patterns. This segmentation allows the system to measure phase differences from multiple directions and positions, enabling calculation of accurate far-field directivity patterns while compensating for asymmetric phase directivity and production errors through geometric diversity.
Solution Approach 2:
The patent deliberately employs asymmetric arrangements of probe antennas relative to the antenna under test, with specific distance relationships (e.g., the second and third probe antennas positioned at different distances from the first probe antenna). This controlled asymmetry, when combined with appropriate signal processing, allows the system to measure and compensate for asymmetric phase directivity effects, ultimately improving measurement precision.
2Productivity
If probe antennas are placed close together to reduce measurement time, then productivity increases, but measurement precision decreases due to mutual interference between probe antennas
Solution Approach 1:
The patent optimizes the spacing parameters between probe antennas based on the wavelength of the electromagnetic waves being measured. By establishing specific distance relationships (e.g., distances of 0.5λ or 0.75λ between adjacent probe antennas), the system achieves an optimal balance where probe antennas are close enough to reduce measurement time but far enough to minimize mutual interference, thereby maintaining measurement precision while improving productivity.
3Ease of manufacture
If standard square waveguide tubes are used for probe antennas, then manufacturing precision and ease of manufacture improve, but measurement precision may be affected by frequency band limitations
Solution Approach 1:
The patent employs standard square waveguide tubes as probe antennas, which are universal components available in standard frequency bands. By using these standardized components with known and predictable electromagnetic characteristics, the system achieves ease of manufacture and consistent performance. The geometric arrangement and signal processing methods compensate for any frequency band limitations, ensuring measurement precision across the operating range.
4Measurement precision
If multiple probe antennas are used to improve measurement precision, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple probe antennas into a unified measurement system where the first, second, and third probe antennas work together to measure phase differences. By combining their signals through appropriate processing (e.g., calculating phase differences between adjacent probe antennas and using these to determine far-field directivity), the system achieves high measurement precision while managing device complexity through integrated signal processing.
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 approach enables high-accuracy phase and amplitude measurements of radio signals from antennas with integrated RF circuits, reducing measurement time and improving sensitivity, while allowing for accurate far-field directivity calculations and phase distribution analysis.
Implementation Method 1
a plurality of probe antennas 12 that receive radio signals at a plurality of measurement positions set in a predetermined measurement plane of a near field region of an antenna 100 to be measured
Data Source
AI summary
A distance between a center of a first probe antenna and a center of a second probe antenna in a measurement plane is longer than a distance between the center of the first probe antenna and a center of a third probe antenna in the measurement plane by a distance between two measurement positions adjacent to each other in a horizontal direction. A distance between a center of a fourth probe antenna and a center of a fifth probe antenna in the measurement plane is longer than a distance between the center of the fourth probe antenna and a center of a sixth probe antenna in the measurement plane by a distance between two measurement positions adjacent to each other in a vertical direction.