Antenna Sidelobe Reduction via Phase Weighting

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Solution Overview

Problem

Conventional radar and communication systems reduce sidelobe interference by amplitude attenuation, which generates heat and reduces efficiency, necessitating improved methods to minimize sidelobe interference.

Innovation Solution

The method involves determining phase weights for antenna elements such that each pair of adjacent elements provides a desired amplitude weight, with phase weight differentials calculated using arccos(2*WA−1), allowing for phase control to achieve the desired amplitude weighting without heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If amplitude attenuation is used to reduce sidelobes, then sidelobe interference is reduced, but heat is generated and system efficiency decreases

Engineering Contradiction:

Improvesidelobe interferenceVSAvoidsystem efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent changes the control parameter from amplitude to phase. Instead of varying the amplitude of signals fed to antenna elements (which causes heat loss), the patent varies only the phase of signals while maintaining constant amplitude. This parameter change achieves sidelobe reduction without the energy loss associated with amplitude attenuation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/electrical amplitude attenuation mechanism with a phase shifting mechanism. Phase shifters are used to control the phase of signals fed to each antenna element, substituting the conventional amplitude control method with a phase-based approach that avoids heat generation while achieving the same sidelobe suppression effect.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If amplitude attenuation is applied to antenna elements, then sidelobe power is minimized, but heat generation increases

Engineering Contradiction:

Improvesidelobe radiationVSAvoidheat generation

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If phase weights are applied to antenna elements, then sidelobe interference is reduced without heat generation, but system complexity increases

Engineering Contradiction:

Improvesidelobe interferenceVSAvoidphase control system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent makes the phase shifters, which are commonly used in phased array systems for beam steering, serve a dual function: both beam steering and sidelobe reduction. By applying appropriate phase weights, the same hardware infrastructure achieves multiple objectives, reducing the need for additional specialized components and mitigating the increase in system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8988279B2Antenna sidelobe reduction using phase only control

Publication Date: 2015.03.24 RAYTHEON CO

AI summary

A method for reducing sidelobe interference in a radar or communication system. The method includes selecting a desired amplitude weight (WD) to be applied to radar or communication antenna elements and determining phase weights for the radar or communication system elements such that each pair of adjacent, phase weighted elements provides the desired amplitude weight when summed.