Mobile Retrodirective Antenna Array Phase Conjugation
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Solution Overview
Problem
Conventional retrodirective antenna arrays require a wired phase distribution network, restricting the mobility and deployment of elements, and are costly due to the need for high RF power to overcome 1/R^2 losses for moderate-to-high RF power density illumination of targets.
Innovation Solution
An active retrodirective antenna array with moving elements that dynamically measure distance to a target, calculate and phase-conjugate RF signals based on this distance and signal frequency, allowing coherent transmission of RF energy to enhance power density without the need for a wired phase reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wired phase distribution network is used to maintain phase coherence, then signal phase consistency is improved, but element mobility and deployment flexibility are restricted
Solution Approach 1:
The patent extracts the phase reference function from the wired network and implements it locally at each element through autonomous distance measurement to the target. Each element independently measures its distance to the target and calculates the required phase shift, eliminating the need for centralized phase distribution through cables.
Solution Approach 2:
Each array element performs self-phase-correction by autonomously measuring its distance to the target and calculating the appropriate phase shift. This self-service mechanism replaces the wired phase distribution network, enabling mobile deployment while maintaining phase coherence across all elements.
2Illumination intensity
If high RF power is used to overcome 1/R^2 losses for moderate-to-high RF power density illumination, then power density on target is improved, but system cost and power requirements increase
Solution Approach 1:
The patent employs feedback through distance measurement to the target, using this information to dynamically adjust the phase of each element's transmitted signal. This feedback mechanism enables coherent signal combining at the target, increasing power density without proportionally increasing individual element power requirements.
Solution Approach 2:
The patent merges the signals from multiple array elements through phase conjugation, causing them to constructively interfere at the target location. This combining effect concentrates the transmitted energy, achieving high power density on target while reducing the power burden on individual elements and the overall system.
3Area of stationary object
If array elements are fixedly dispersed over a wide area, then coverage area is improved, but rapid deployment and reconfiguration capability are reduced
Solution Approach 1:
The patent transitions from fixed to mobile array elements that can dynamically reposition themselves. Each element independently measures its distance to the target and adjusts its phase accordingly, enabling rapid deployment and reconfiguration while maintaining functional performance across wide areas.
Solution Approach 2:
The patent changes the operational parameters of each element based on its dynamic position relative to the target. By continuously measuring distance and adjusting phase shifts, the system adapts to different geometries and configurations, enabling both wide coverage and rapid redeployment without physical reconfiguration of the array 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
Enables lower-cost, rapidly deployable, and mobile RF energy illumination with enhanced power density on targets, as elements can be smaller, cheaper, and easily redeployed, while maintaining coherent signal addition at the target.
Implementation Method 1
calculating a phase utilizing the measured distance to the area of the target and a frequency of the extracted RF pilot signal, by each element; phase conjugating the RF pilot signal based on the calculated phase, by each element
Implementation Method 2
The phase conjugated RF signals transmitted by the plurality of moving elements adds coherently at the area of virtual beacon illumination on the target to enhance power density on the target
Data Source
AI summary
Method and system for directing RF energy from an active retrodirective antenna array including moving elements onto a target includes: receiving a beacon from the target by each element, the scattered beacon including an RF pilot signal imposed thereon, extracting the RF pilot signal from the received scattered optical beacon, dynamically measuring a distance to an area of optical beacon illumination on the target, calculating a phase utilizing the measured distance to the area of the target and a frequency of the extracted RF pilot signal, phase conjugating the RF pilot signal based on the calculated phase, and transmitting the phase conjugated RF signal towards the target; by each element, where the phase conjugated RF signal transmitted by each element add coherently at the area of optical beacon illumination on the target to enhance power density on the target.