Optical Interposer for Array Antennas Signal Loss
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Solution Overview
Problem
Conventional corporate distribution structures for phased array antenna systems suffer from signal degradation due to ohmic, dielectric, and radiative losses, especially at higher frequencies, and require co-location with RF digital/analog components, posing challenges in form factor and signal integrity.
Innovation Solution
An optical interposer with a photonic substrate that uses optical waveguides and opto-electronic conversion devices to distribute and process RF signals, minimizing electrical signal propagation and enabling efficient optical communication between an optical signal source and antenna elements, thereby reducing signal degradation and mechanical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a corporate distribution structure is used to interface between signal source and antenna elements, then signal distribution is facilitated, but signal degradation occurs due to ohmic, dielectric, and radiative losses
Solution Approach 1:
The patent replaces the electrical corporate distribution structure with an optical distribution network. Optical fibers substitute for electrical transmission lines, and optical components (couplers, switches, modulators) replace electrical signal distribution components. This substitution eliminates ohmic losses in metal conductors and dielectric losses in PCB substrates, directly resolving the signal degradation problem while maintaining signal distribution functionality.
2Device complexity
If RF digital/analog components are co-located with antenna elements, then form factor is reduced, but signal integrity deteriorates due to increased losses
Solution Approach 1:
The patent introduces an optical intermediary layer between the central control system and antenna elements. Optical fibers serve as intermediaries to transmit control signals and power to RF components located near antenna elements, while optical return paths carry received signal information back to central processing. This intermediary optical infrastructure enables component co-location for compact form factor while maintaining signal integrity by isolating RF components from lossy electrical interconnects.
3Power
If the number of antenna elements is increased to mitigate propagation loss, then antenna gain increases, but signal degradation in the distribution network worsens
Solution Approach 1:
The patent replaces the electrical distribution network with an optical one to support scaled antenna arrays. Optical fibers and couplers enable low-loss distribution to a large number of antenna elements, allowing the array size to be increased for higher gain without being constrained by electrical loss mechanisms. The optical infrastructure scales efficiently with array size, resolving the contradiction between array scaling for gain and distribution network losses.
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 optical interposer significantly reduces signal loss and mechanical complexity by using optical communication, allowing for a more integrated and robust antenna system with reduced electrical transmission lengths and supporting wideband operation without the need for one fiber per antenna element.
Implementation Method 1
optical interface which is configured to facilitate an optical communication link with a remote optical signal source
Implementation Method 2
element-level optical waveguides...configured to optically couple the ELOC signals to a plurality of conversion locations
Implementation Method 3
Each photodetector is configured to convert one of the ELOC signals to an element-level modulated radio frequency (ELMRF) signal. This is accomplished by extracting from the ELOC the RF signal which was modulated on the optical carrier.
Data Source
AI summary
Feeding a plurality of antenna elements of an array antenna, involves receiving at a photonic substrate at least one transmit modulated optical carrier (TMOC) signal. The TMOC signal is communicated to an array level photonic integrated circuit (ALPIC) disposed on the photonic substrate where one or more optical processing operations are performed involving the TMOC signal to obtain a plurality of element-level optical carrier (ELOC) signals. These ELOC signals are communicated from the ALPIC to a plurality of conversion locations distributed on the photonic substrate. Photodetectors respectively provided at the conversion locations convert each of the ELOC signals to an element-level modulated radio frequency (ELMRF) signal. The ELMRF signal are coupled from each photodetector respectively to one of the plurality of antenna elements.