Antenna Device Reducing Sidelobe Levels via Time-Integrated Signal Processing
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Solution Overview
Problem
Conventional antenna devices face increased hardware costs due to complex power supply circuits and the need for multiple expensive variable attenuators to accurately control sidelobe levels for both sum and difference patterns, which complicates the formation of desired radiation patterns without escalating hardware costs.
Innovation Solution
An antenna device with a configuration that includes sub-array antennas, phase shifters, electric power combining units, and a signal combining unit, where the excitation phases are changed to generate composite signals for sum and difference patterns, and the radiation patterns are formed by time-integrating phase-shifted signals, allowing for reduced sidelobe levels without increasing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If variable attenuators are used to control amplitude of element antennas for sidelobe reduction, then sidelobe levels are reduced, but hardware cost increases
Solution Approach 1:
The patent replaces the mechanical/electrical system of variable attenuators with a signal processing approach. Instead of using physical attenuators to control amplitude, the system uses digital signal processing to generate excitation signals with different amplitude distributions. This substitution eliminates the need for expensive variable attenuators while achieving the same amplitude control function through software-based signal generation.
Solution Approach 2:
The patent changes the parameter of amplitude distribution from a fixed hardware-controlled parameter to a time-variable software-controlled parameter. By generating excitation signals with different amplitude characteristics through signal processing, the system dynamically adjusts the amplitude distribution parameter without requiring physical hardware changes. This allows the system to achieve optimal amplitude distribution for different patterns without the cost of variable attenuators.
2Object-generated harmful factors
If power supply circuit is divided into two portions for central and perimeter elements with two monopulse comparators, then sidelobes of both sum and difference patterns are reduced, but hardware cost and complexity increase
Solution Approach 1:
The patent applies universality by making a single monopulse comparator perform multiple functions through time-division operation. The same comparator is used to process both sum pattern signals and difference pattern signals by switching between different excitation modes. This eliminates the need for separate comparators for sum and difference patterns, reducing hardware complexity while maintaining the ability to achieve low sidelobes for both patterns through sequential processing.
Solution Approach 2:
The patent merges the separate power supply circuits and comparators into a unified system. Instead of having independent power supply circuits for central and perimeter elements with separate comparators, the system uses a single power supply and a single comparator that processes both sum and difference pattern signals through time-division multiplexing. This consolidation reduces hardware complexity while achieving the same sidelobe reduction performance through coordinated signal processing.
Data Source
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AI summary
Disclosed is an antenna device in which an excitation phase changing unit (4) for changing the excitation phases of element antennas (2-1n) to (2-8n) by controlling phase shifters (3-1n) to (3-8n) dependently on preset phase values is disposed, and every time the excitation phases are changed by the excitation phase changing unit (4), a radiation pattern forming unit (12) shifts the phases of a sum signal and a difference signal, and forms a monopulse sum pattern by time-integrating the sum signal after phase shift and also forms a monopulse difference pattern by time-integrating the difference signal after phase shift.