Phased Array Antenna Analog Beamforming Nulling

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Solution Overview

Problem

Digital beamformers in phased array antennas have a limited dynamic range, making them vulnerable to high power interfering signals, which can saturate the system and render it inoperative, and existing solutions to increase dynamic range are costly or reduce scanning capability.

Innovation Solution

Incorporating an analogue beamforming layer before the digital signal processor to create regions of near zero directivity or nulls in the direction of interfering signals, thereby reducing exposure to these signals without reducing the number of digital beamforming control points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If digital beamforming is used to generate multiple spot beams, then a large number of narrow spot beams can be achieved, but the system becomes vulnerable to high power interfering signals due to limited dynamic range

Engineering Contradiction:

Improvenumber of spot beamsVSAvoidvulnerability to interfering signals

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The antenna elements are divided into multiple subarrays, with each subarray processed by a separate beamforming channel. This segmentation allows independent control of null formation in each subarray, enabling the system to handle multiple interfering signals from different directions while maintaining multiple spot beams for communication

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different beamforming weights to different subarrays based on the spatial distribution of interfering signals. Each subarray is optimized to create nulls in specific directions where interference is present, while maintaining beamforming capability in other directions for communication signals

Inventive Principle:

Principle #3Local quality

2Reliability

If the dynamic range of digital beamformers is increased to handle high power interfering signals, then system reliability improves, but the cost increases significantly

Engineering Contradiction:

Improveresistance to interfering signalsVSAvoidcost of digital beamformer

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary processing of interfering signals in the analog domain before digital conversion. By forming nulls in the analog beamforming stage, high power interfering signals are attenuated before reaching the digital beamformer, preventing saturation and allowing the use of lower dynamic range digital processors

Inventive Principle:

Principle #10Preliminary action

3Reliability

If analog beamforming is used to create nulls for interfering signals, then exposure to interfering signals is reduced, but the number of beamforming control points decreases

Engineering Contradiction:

Improveprotection from interfering signalsVSAvoidscanning capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The antenna array is divided into multiple subarrays, each with its own beamforming control points. This segmentation allows the system to form nulls using only a subset of control points in each subarray, while other control points remain available for scanning and beam steering operations, maintaining full adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extends the beamforming control from a single planar array to a three-dimensional configuration with multiple subarrays at different positions and orientations. This adds spatial dimensionality to the control points, allowing null formation in specific directions without limiting the scanning capability in other directions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 analogue beamforming layer effectively blocks interfering signals from reaching the digital beamformers, preventing system malfunction while maintaining full flexibility and scanning capability, ensuring reliable operation even under high interference conditions.

Implementation Method 1

beamforming the signals received or transmitted by the antenna

Methodology Applied

Scientific EffectBeamforming:

Implementation Method 2

create regions of near zero directivity or nulls in the direction of interfering signals

Methodology Applied

Scientific EffectNull formation:

Data Source

PatentEP2586097B1An antenna

Publication Date: 2017.10.25 ASTRIUM LTD

AI summary

A phased array antenna for providing a radiation pattern comprising at least one communication beam, the antenna comprising a plurality of antenna elements, each antenna element having an antenna element signal having a phase relationship and an amplitude relationship to the other element signals; a digital signal processing arrangement providing a digital beamforming network; and an analogue beamforming network arranged to reduce exposure of the digital signal processing arrangement to an interfering signal, the analogue beamforming network being configured to apply analogue beamforming weights selected to generate a null in the radiation pattern in a direction corresponding to the interfering signal to signals received from said antenna elements and the digital beamforming network being configured to apply digital beamforming weights for each of said at least one communication beams to signals received from said analogue beamforming network such that the composite radiation pattern of the antenna provides said at least one communication beams. The elements may be partitioned into subarrays, the analogue beamforming network applying beamforming weights to each antenna element within a subarray and the digital beamforming network applying beamforming weights to each subarray.