Omnidirectional Sensor with Dielectric Mirrors for RF and Optical Signals
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Solution Overview
Problem
Current sensing systems face challenges in integrating radio frequency (RF) and optical/infrared (O/IR) signals due to material limitations, which affect signal propagation and reliability, especially in high clutter environments and stealth target detection, where RF systems are unreliable and O/IR provides better angular resolution but is less effective in certain environmental conditions.
Innovation Solution
A multi-modal omnidirectional sensor system using a reflective focusing aperture with tapered square prismatic cells and non-metallic dielectric mirrors that are reflective to optical signals while being transparent to RF signals, allowing simultaneous and undistorted reception of both signal types across various wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal or magnetic material based antennas are used to concentrate RF electromagnetic energy, then RF signal reception is improved, but optical/IR signal transmission is attenuated or obscured
Solution Approach 1:
The aperture is divided into multiple discrete antenna elements arranged in a grid pattern, with each element having specific dimensions and spacing. This segmentation allows RF signals to be received by individual elements while the overall structure remains transparent to optical/IR wavelengths, resolving the contradiction between RF reception and optical transmission.
Solution Approach 2:
Different regions of the aperture have different properties: the antenna elements themselves are optimized for RF reception with appropriate impedance and geometry, while the spaces between elements and the overall aperture structure are designed to be transparent to optical/IR signals. This local differentiation allows each region to perform its specific function without interfering with the other modality.
2Reliability
If optical/IR concentrators made from bulk dielectric materials are used, then optical/IR energy concentration is improved, but RF wave propagation is affected and properties change with wavelength variations
Solution Approach 1:
Instead of using bulk dielectric materials that affect RF propagation, the system segments the aperture into discrete antenna elements with spacing optimized for RF wavelengths. This segmentation eliminates the wavelength-dependent propagation issues associated with bulk dielectrics while maintaining optical/IR transparency through the inter-element spaces.
Solution Approach 2:
The antenna elements act as intermediaries that selectively interact with RF signals while being transparent to optical/IR signals. The elements are designed with dimensions and spacing that create a transmission window for optical wavelengths while providing effective RF signal reception and concentration through coherent integration.
3Measurement precision
If optical components are rotated toward the direction of interest using gimbal, then angular resolution is improved, but RF propagation patterns become more complicated
Solution Approach 1:
The aperture structure serves multiple functions simultaneously: it provides angular resolution through the spatial distribution and phase control of antenna elements without requiring mechanical rotation. The same structure that receives RF signals also maintains a consistent transmission pattern for optical/IR signals, eliminating the need for gimbals and complex mechanical positioning.
Solution Approach 2:
The mechanical gimbal system is replaced with an electronic beam-forming approach using phased array techniques. By controlling the phase and amplitude of signals from individual antenna elements, the system achieves angular resolution and directional sensitivity without any moving parts, maintaining simple and consistent propagation patterns for both RF and optical signals.
4Reliability
If discrete, spatially separated sensors for RF and O/IR are used, then modality-specific detection is improved, but information exchange complexity and data processing complexity increase substantially
Solution Approach 1:
The RF antenna elements and optical/IR detector array are merged into a single collocated sensor platform with co-aligned apertures and shared structural support. This integration eliminates the need for complex spatial registration and alignment between separate sensors, while the unified data processing architecture fuses RF and optical data streams at the source, reducing overall system complexity.
Solution Approach 2:
The integrated sensor platform performs multiple detection functions simultaneously using the same physical aperture and structural framework. The system processes both RF and optical/IR signals through a unified data processing architecture that leverages the complementary information from both modalities without requiring separate information exchange channels or complex coordination between discrete sensors.
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 solution enables efficient and reliable detection and identification of targets with improved angular resolution and reduced weight, power consumption, and vulnerability to countermeasures, by using a reflective focusing system that maintains signal quality across different spectral bands without chromatic aberrations.
Implementation Method 1
non-metallic dielectric mirrors that are reflective to optical signals
Implementation Method 2
non-metallic dielectric mirrors that are reflective to optical signals while being transparent to RF signals
Implementation Method 3
reflective focusing aperture with tapered square prismatic cells
Data Source
AI summary
A multi-modal omnidirectional sensor includes an ovaloid aperture having a plurality of tapered square prismatic cells formed from a plurality of partition walls. A focal ovaloid is concentric with the ovaloid aperture, and the focal ovaloid has an outer surface dimension that coincides with a focal distance of the ovaloid aperture. A multi-mode sensor array is disposed on the focal ovaloid, and is configured to receive an optical signal and a radio frequency (RF) signal. One of the plurality of partition walls comprises a non-metalic dielectric mirror. One of the plurality of partition walls is configured to be reflective to a band of desired wavelengths of the optical signal while being transparent to the RF signal.