Airborne Radar Waveguide Power Distribution for 360-Degree Coverage

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Solution Overview

Problem

Current airborne radar systems face limitations in providing full 360° coverage without additional antennas, are costly, heavy, and complex in design and manufacturing, especially when trying to achieve forward and rearward looking capabilities without compromising on weight, drag, and performance.

Innovation Solution

The antenna system incorporates a dorsal unit with polarized waveguides mounted on top, bottom, or inside, distributing microwave power to both side-looking and height-direction antenna elements, allowing for azimuthal and elevation scans without additional nose or tail antennas, using existing T/R-units for phase control, which simplifies design and manufacturing while maintaining lightweight and low-cost requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional antennas are placed in the front and rear of the dorsal unit for forward and rearward looking, then full 360° coverage is achieved, but weight and system complexity increase

Engineering Contradiction:
Improvecoverage angleVSAvoidantenna weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The existing T/R-units and waveguide system are made multi-functional by configuring them to serve both the original side-looking antenna elements and the new forward/rearward looking antenna elements. The same microwave power distribution system feeds all antenna elements, eliminating the need for separate radar systems and reducing overall weight.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the forward and rearward looking antenna functions with the existing side-looking dorsal unit by using a common microwave power distribution system and T/R-units. This consolidation eliminates duplicate components and reduces total system weight while achieving full 360° coverage.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If separate radar systems are used for forward and rearward looking antennas, then full coverage is achieved, but system cost increases

Engineering Contradiction:
Improvecoverage angleVSAvoidsystem cost
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single radar system with universal T/R-units is designed to control all antenna elements (side-looking and forward/rearward looking) through a common microwave power distribution system, eliminating the need for multiple separate radar systems and reducing overall system cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If forward and rearward looking antennas are connected to a common radar with long high-power RF feeds, then full coverage is achieved, but weight increases due to heavy RF feeds

Engineering Contradiction:
Improvecoverage angleVSAvoidRF feed weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The invention replaces heavy mechanical RF feed systems with lightweight waveguide structures that integrate directly into the dorsal unit. The waveguides provide a compact, low-weight pathway for microwave power distribution to all antenna elements, eliminating the need for long high-power RF cables.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If endfire array with monopoles is used on the dorsal unit, then forward and rearward looking is achieved, but manufacturing complexity and electromagnetic design complexity increase

Engineering Contradiction:
Improvelooking directionVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The antenna system is segmented into modular components: the existing dorsal unit with side-looking elements, and additional forward/rearward looking antenna elements. Each segment uses standard waveguide and T/R-unit components that can be manufactured and assembled independently, reducing overall manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

5Adaptability or versatility

If endfire array with monopoles is used, then forward and rearward looking is achieved, but an undesirable upwards lobe tilt occurs

Engineering Contradiction:
Improvelooking directionVSAvoidlobe tilt control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention controls the electromagnetic parameters (phase and amplitude) of the microwave signals fed to each antenna element through the T/R-units to achieve the desired radiation pattern. By adjusting these parameters, the system achieves forward and rearward looking capability without the undesirable upward lobe tilt that occurs with endfire arrays.

Inventive Principle:
Principle #35Parameter changes

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

This configuration enables efficient 360° coverage with reduced weight and drag, improved performance, and controllable lobe widths, eliminating the need for intricate scan control and costly additional antennas, while maintaining aerodynamic efficiency and simplicity in integration.

Implementation Method 1

The power distribution system comprises an assembly of waveguides (6) coupled to a number of antenna devices (18). The antenna devices (18) comprise a number of second antenna elements (7) being fed by the power generator (5) via the power distribution system (3).

Methodology Applied
Scientific EffectWaveguide: Waveguide

Implementation Method 2

The antenna devices (18) are connected to the waveguides (6) so that the microwave power supplied by the first T/R-units (4) can be distributed in such a way that an azimuthal scan can be performed by the radar system in the forward and/or in the rearward sectors.

Methodology Applied
Scientific EffectPhase control: Phase Modulation

Implementation Method 3

The antenna system (1) comprises a dorsal unit (8) extending in a longitudinal direction, a lateral direction and a height direction. The dorsal unit (8) comprises two opposing long sides (9) extending in a height direction (Z) and a longitudinal direction (X).

Methodology Applied
Scientific EffectRadar: Radar

Data Source

PatentEP2122759B1Microwave power distribution system for an airborne radar system
Publication Date: 2019.02.20 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2122759B1 patent drawingFigure 1
  • EP2122759B1 patent drawingFigure 2
  • EP2122759B1 patent drawingFigure 3

AI summary

The invention relates to an antenna system (1) for an airborne radar system. The antenna system (1) comprises a number of first antenna elements (2) and a microwave power distribution system (3) comprising a number of first T/R-units (4) being coupled to the first antenna elements (2) for distribution of microwave power to the first antenna elements (2). The invention is characterized in that the microwave power distribution system (3) comprises an assembly of waveguides (6; 6a; 6b) coupled to a number of second antenna elements (7) directed at an angle essentially perpendicular to the number of first antenna elements (2), wherein the first T/R-units (4) are coupled to the waveguides (6; 6a) for distribution of microwave energy to the second antenna elements (7).