Phased Array Antenna Beam Steering and Side Lobe Control
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Solution Overview
Problem
High-gain antennas face challenges in rapid re-aiming, significant side lobe effects, and the inability to simultaneously monitor multiple directions, with existing technologies taking hundreds of milliseconds to seconds to re-aim and experiencing substantial side lobe interference.
Innovation Solution
An array of antenna elements adjustably coupled to a common reference signal, allowing for rapid switching between multiple patterns to minimize side lobes and achieve re-aiming in tens of nanoseconds, enabling quick dithering and simultaneous scanning and tracking with reduced side lobe clutter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a parabolic reflector antenna is used to achieve high gain, then the antenna gain is improved, but the re-aiming time increases to hundreds of milliseconds or longer
Solution Approach 1:
The patent replaces the mechanical re-aiming system of a parabolic reflector antenna with an electronically controlled phased array system. Instead of physically rotating the entire antenna structure using servomotors, the beam direction is changed by electronically adjusting the phase shifters associated with each antenna element. This substitution of mechanical movement with electronic control enables rapid beam steering in tens of nanoseconds while maintaining high gain through constructive interference of signals from multiple elements.
Solution Approach 2:
The patent divides the antenna system into multiple discrete antenna elements, each equipped with its own phase shifter. This segmentation allows independent control of each element's signal phase and amplitude, enabling electronic beam steering without moving the entire antenna structure. The segmented approach transforms a single mechanical re-aiming problem into multiple independent electronic control channels.
2Loss of time
If a phased-array antenna is used to enable fast re-aiming, then the re-aiming time is reduced to tens of nanoseconds, but the device complexity increases due to hundreds or thousands of phase shifters
Solution Approach 1:
The patent merges the functions of multiple phase shifters and signal paths into a unified phased array control system. By coordinating the phase and amplitude adjustments across all antenna elements through a centralized control mechanism, the system achieves fast beam steering without requiring each element to have fully independent complex control circuitry. This merging reduces overall system complexity while maintaining the fast re-aiming capability.
Solution Approach 2:
The patent designs the phased array system with multi-functional capability, where the same array of antenna elements and phase shifters can perform multiple functions including fast beam steering, side lobe suppression, and simultaneous monitoring of multiple directions. This universality reduces the need for separate specialized systems for each function, thereby reducing overall device complexity.
3Measurement precision
If a single-beam high-gain antenna is used to focus energy in one direction, then the antenna gain is improved, but the ability to monitor multiple directions simultaneously is lost
Solution Approach 1:
The patent implements dynamic beam steering capability through electronic control of phase shifters, allowing the antenna beam to be rapidly redirected between multiple directions without physical movement. This dynamic control enables the system to maintain high gain in the current direction while quickly switching to monitor other directions, providing both focused energy transmission and multi-directional monitoring capability through time-multiplexed beam steering.
Solution Approach 2:
The patent employs periodic scanning of multiple directions by rapidly switching the beam direction between different angular positions in a systematic sequence. This periodic action allows the antenna to monitor multiple directions by sequentially focusing the beam on each direction, maintaining high gain during each focus while achieving comprehensive multi-directional coverage through the repeating scan pattern.
4Speed
If a phased-array antenna is used to enable fast beam switching, then the re-aiming speed is improved, but side lobe interference increases
Solution Approach 1:
The patent adjusts the phase and amplitude parameters of signals fed to individual antenna elements to optimize the radiation pattern. By carefully controlling these parameters, the system achieves fast beam switching while suppressing side lobes through constructive interference in the main beam direction and destructive interference in side lobe directions. This parameter optimization resolves the contradiction between fast switching and side lobe suppression.
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 high-gain antenna re-aiming in tens of nanoseconds, significantly reducing side lobe interference and allowing for efficient interleaved scanning and scrutiny, enhancing data collection bandwidth and precision in radar applications.
Implementation Method 1
Each phase shifter propagates the signal to its respective antenna element after applying its commanded phase shift to the signal. By design, the energy radiated by each antenna element adds in free space to yield a focused beam in a particular direction.
Data Source
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Figure 4
AI summary
An embodiment of an antenna comprises an array of antenna elements arranged in groups of antenna elements adjustably coupled to respective reference waves. A multiplicity of patterns of antenna coupling settings are defined, each of which gives rise to a main lobe which points the antenna in a particular direction, each pattern also giving rise to respective side lobes. First and second such patterns may point the antenna in the same direction but with non-identical side lobes. In this way the clutter level from the side lobes relative to the main lobe is much smaller than would be the case if one of the patterns were employed both for transmitting and receiving. Alternatively, the first and second patterns may be used in quick succession both for transmitting, or used in quick succession both for receiving. The antenna may also switch rapidly between patterns where the main lobe points in a different direction in each pattern, allowing dithering of the beam or rapid switching between scanning and tracking.