Dish Antenna Array Calibration Over Fiber for End-to-End Phase Alignment
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Solution Overview
Problem
Conventional methods for synchronizing large arrays of dish antennas over long distances, such as 1 km, fail to account for complete end-to-end optical and RF pathways, leading to inadequate phase alignment due to high cable loss and signal degradation.
Innovation Solution
Utilizing linear RF over fiber components with remote boundary condition (RBC) short open load (SOL) RF calibration to distribute common clock and RF test signals over a single mode fiber, enabling phase alignment and compensation for phase changes in the entire RF-to-optical-to-RF path at each dish antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional coaxial cable distribution methods are used for phase alignment, then the system is simple to implement, but cable loss increases significantly over long distances exceeding 1 km
Solution Approach 1:
The patent replaces the mechanical/electrical coaxial cable distribution system with an optical fiber distribution system. RF signals are converted to optical signals for transmission over SMF, eliminating the high cable loss associated with coaxial cables over long distances. The optical domain substitution allows signal distribution over 1+ km without significant loss.
Solution Approach 2:
The patent introduces optical fiber as an intermediary medium between the data center and remote dish antennas. Instead of directly transmitting RF signals through lossy coaxial cables, the system uses optical fiber as a mediator to carry the signals over long distances with minimal loss, then converts back to RF at the destination.
2Stability of the object's composition
If analog feedback method is used to correct phase changes in fiber, then single mode fiber stability is improved, but the complete end-to-end optical and RF pathways are not addressed
Solution Approach 1:
The patent implements a feedback mechanism where the system measures the actual phase of RF signals after they have traversed the complete end-to-end pathway (RF-to-optical-to-RF). The measured phase information is used to generate correction factors that compensate for phase changes accumulated throughout the entire signal path, not just in the fiber portion.
Solution Approach 2:
The patent divides the calibration process into segmented measurements. Instead of treating the entire end-to-end path as a single measurement, the system performs separate measurements of different segments (forward path, reverse path) and combines them to achieve complete pathway compensation. This allows precise correction of phase errors in each segment.
3Measurement precision
If remote boundary condition SOL RF calibration is performed at each dish antenna, then phase alignment accuracy is improved, but measurement equipment and RF sources are required at each location
Solution Approach 1:
The patent makes the data center measurement equipment multi-functional by enabling it to perform calibration functions for multiple remote dish antennas through the optical fiber network. Instead of requiring dedicated calibration equipment at each dish location, the universal measurement system at the data center can calibrate any number of remote antennas by transmitting calibration signals through the fiber network and receiving responses back.
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
Provides accurate phase alignment and compensation for dish antenna arrays distributed over long distances, maintaining alignment despite temperature, time, and physical movement, with a low-complexity and cost-effective solution.
Implementation Method 1
linear RF over fiber components located at a data center and each dish antenna provides a bidirectional path connection via one SMF
Implementation Method 2
linear electrical/optical and optical/electrical components
Data Source
AI summary
Described herein is an apparatus and a method for an antenna array calibration device and method. The device comprises a radio frequency/optical (RF/optical) data center having at least one optical input/output; N single mode fibers (SMF) each having a proximal end connected to the at least one optical input/output of the RF/optical data center and a distal end, where N is a positive integer; N optical/RF dish calibrators each having an optical input/output connected to the distal end of the at least one SMF input/output; N coaxial transmission lines each having a proximal end connected to one of the RF input/output of the N optical/RF dish calibrators and a distal end; and N dish antennas each connected to the distal end of one of the N coaxial transmission lines.