Millimeter Wave Illumination System With Rotating Baffle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Millimeter and sub-millimeter wave imaging systems face challenges in indoor environments due to similar temperature elements causing insufficient contrast, and the speckle effect from narrow bandwidth illuminators leading to uneven illumination and spatial variations in output power.
Innovation Solution
A system that generates multiple radiation field states within a predetermined time interval by altering the electromagnetic field pattern before radiation exits, using a baffle with transmissive exit apertures and a reflective surface, or by employing multiple incoherent sources or phase shifting, to reduce spatial variations in output power and achieve more even illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a narrow bandwidth illuminator is used, then the speckle effect is reduced, but spatial variations in output power increase causing uneven illumination
Solution Approach 1:
The patent employs a rotating baffle with multiple apertures that dynamically changes the radiation field state over time. This dynamic element introduces temporal variation to average out spatial power fluctuations, transforming a static uneven illumination problem into a dynamically balanced system that delivers uniform time-averaged illumination.
Solution Approach 2:
The system changes the radiation field state parameter by rotating the baffle to different angular positions, thereby altering which apertures are active and how radiation paths are configured. This parameter change over time allows the system to average multiple radiation patterns, reducing spatial variations in output power.
2Reliability
If multiple radiation field states are generated rapidly, then spatial variations are reduced, but device complexity increases
Solution Approach 1:
The baffle is segmented into multiple discrete apertures arranged in concentric circles, allowing the system to generate multiple radiation field states through simple rotation. Each aperture configuration creates a distinct radiation pattern, and the segmentation enables easy generation of diverse field states without complex mechanical adjustments.
Solution Approach 2:
The baffle rotates periodically to cycle through different aperture configurations, generating multiple radiation field states in a repeating sequence. This periodic action ensures that over one full rotation cycle, the system averages multiple radiation patterns, reducing spatial variations while maintaining a simple, predictable mechanical structure.
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 generation of multiple radiation field states results in reduced spatial variations in output power, providing a more consistent and even illumination, which improves image quality by averaging the radiation patterns over the integration time of the imager, thereby reducing the speckle effect and enhancing contrast.
Implementation Method 1
a surface reflective at millimeter or sub-millimeter wavelengths for inducing a plurality of radiation paths between the source and the baffle
Data Source
AI summary
An improved millimeter wave illumination system includes at least one primary source of millimeter wave radiation, a reflecting surface and a baffle comprising a plurality of exit apertures arranged such that at least some of the radiation from the source is reflected from the reflective surface before proceeding to the baffle, characterized in that means are incorporated for generating a plurality of radiation field states within a pre-determined time interval. The baffle, source and reflector are preferably packaged into a container with the exit apertures providing an illumination output. The generation of the plurality of radiation field states provides an illumination at the illuminator output that is less spatially variable when integrated over the pre-determined time interval. Embodiments of the invention show means for generating the plurality of radiation field states including relative movement of the reflective surface, variable positioning of the source with respect to the reflective surface, and including multiple sources within a single system.