Toroidal Compact Antenna Test Range Quiet Zone
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Solution Overview
Problem
Current antenna test range technologies face challenges in generating uniform plane waves with minimal reflections, refractions, and diffractions, leading to increased quadratic phase error and reduced power density at the receiving antenna due to the need for large distances and complex edge treatments, which complicates the measurement of antenna and radar target power patterns.
Innovation Solution
A toroidal reflector is used as the main reflector in a compact antenna test range, eliminating edge discontinuities and allowing for the generation of multiple directional plane waves, simplifying the positioner complexity for two and three-dimensional power pattern measurements, and enabling a larger quiet zone with reduced ripple field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance R between transmitter/receiver and AUT is increased to reduce quadratic phase error, then the phase error is reduced, but the receiving power at the receiver decreases due to 1/R2 power density relationship
Solution Approach 1:
The patent employs a spherical main reflector instead of a planar one. The spherical geometry enables the reflected waves to converge and form a plane wave front in the far field region, achieving the required phase uniformity without requiring extremely large distances. The curvature of the spherical reflector compensates for the spherical wave front from the feed antenna, transforming it into a plane wave front in the quiet zone.
2Object-generated harmful factors
If a traditional reflector design is used, then edge diffraction occurs requiring complex edge treatments, but the toroidal reflector eliminates edge discontinuities
Solution Approach 1:
The toroidal reflector uses a curved toroidal surface geometry that naturally eliminates sharp edges and discontinuities. The continuous curved surface ensures smooth wave propagation without edge diffraction effects, removing the need for complex edge treatments while maintaining or improving the quality of the plane wave generation in the quiet zone.
3Adaptability or versatility
If multiple directional plane waves are generated for comprehensive measurement, then measurement coverage is improved, but the positioner complexity increases
Solution Approach 1:
The toroidal reflector system divides the measurement space by generating multiple directional plane waves from different orientations. Each plane wave provides measurement coverage for specific angular ranges, and by combining multiple such waves, comprehensive three-dimensional measurement coverage is achieved. This segmentation approach allows complete measurement capability while keeping the positioner relatively simple compared to systems requiring complex multi-axis mechanisms.
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 toroidal reflector design simplifies the generation of uniform plane waves, reduces edge diffraction, and enhances the quiet zone size, improving the accuracy and efficiency of antenna and radar target power pattern measurements while maintaining a simpler positioner configuration.
Implementation Method 1
The spherical wave which radiated by the feed antenna is reflected by sub-reflector. The reflected spherical wave incidents at the toroidal main reflector. The wave reflected by the toroidal main reflector is a plane wave
Data Source
AI summary
This invention describes the technology of toroidal CATR (compact antenna test range) for generating multiple directional plane waves propagate toward the center axis of QZ (quiet zone). The toroidal CATR consists of torus as main reflector, sub-reflectors, and the corresponding feed antennas of sub-reflectors. This invention is to provide multiple directional plane waves propagating toward the center axis of torus which is also the center axis of QZ. The performances of QZ in this invention are with larger size of QZ and better electrical performance inside QZ. Due to the capability of multiple directional plane waves propagating toward the center axis of QZ, the complexity of positioner (turntable) for AUT (antenna under test) or radar target RCS (radar cross section) in three dimensional power pattern measurement will be simplified.