Single-Ridge Waveguide Slot Antenna for Circular Polarization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing slot waveguide antennas face challenges in achieving dual polarization and wide bandwidth with low insertion losses and compact design, particularly in applications requiring beam steering and efficient circular polarization control.

Innovation Solution

A single-ridge waveguide antenna with specifically arranged and shaped slots, allowing for phase matching and efficient circular polarization, reduces insertion losses and grating lobes, enabling dual polarization and a large working bandwidth through a compact structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional parabolic antennas are used, then high gain and directional radiation are achieved, but volume and weight increase significantly

Engineering Contradiction:
Improveantenna volumeVSAvoidradiation gain
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The antenna is segmented into multiple radiating slots arranged in a planar array configuration, allowing the radiation function to be distributed across multiple elements rather than concentrated in a single large parabolic structure. This segmentation enables achieving directional radiation through constructive interference of waves from multiple slots while maintaining a compact planar form factor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a three-dimensional parabolic reflector structure to a two-dimensional planar slot array. By arranging multiple slots in a planar configuration with specific spacing and feeding phases, the antenna achieves beam steering and directional radiation capabilities traditionally associated with large 3D structures, but with dramatically reduced volume and weight.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If planar slot arrays are used for beam steering, then radiation direction can be modified, but the supply network becomes complex and expensive

Engineering Contradiction:
Improvebeam steering capabilityVSAvoidsupply network complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The waveguide structure serves multiple functions simultaneously: it acts as the feeding network for all slots, provides the structural support for the planar array, and enables beam steering through its inherent phase progression characteristics. This multi-functionality eliminates the need for separate complex feeding networks with individual phase shifters and amplitude controllers for each slot.

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

Solution Approach 2:

The waveguide-fed slot array structure is self-configuring for beam steering. By properly positioning the slots along the waveguide and utilizing the natural phase progression of the waveguide mode, the system achieves beam steering capability without requiring external control mechanisms or complex electronic phase shifters at each slot location.

Inventive Principle:
Principle #25Self-service

3Reliability

If slots are arranged to achieve circular polarization, then polarization control is improved, but insertion losses increase

Engineering Contradiction:
Improvepolarization controlVSAvoidinsertion loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention introduces a single ridge in the waveguide that creates local asymmetry in the electromagnetic field distribution. This localized structural modification causes the dominant TE10 mode to degenerate into two orthogonal modes with a 90-degree phase difference, naturally producing circular polarization without requiring complex slot arrangements or additional polarizing elements that would increase losses.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By modifying the waveguide geometry parameter (adding a single ridge), the invention changes the electromagnetic mode characteristics from linear polarization to circular polarization. This parameter change in the waveguide structure inherently provides the phase quadrature needed for circular polarization while maintaining efficient power transmission and low insertion losses.

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If compact planar structures are used, then volume is reduced, but bandwidth is limited

Engineering Contradiction:
Improveantenna volumeVSAvoidoperating bandwidth
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The invention utilizes the frequency-dependent characteristics of the waveguide mode and the interference pattern from the planar slot array to achieve wide bandwidth. The phase progression and beam steering capability are maintained across a wide frequency range by exploiting the dynamic response of the waveguide structure, allowing the compact planar design to support wide operating bandwidth without requiring active tuning mechanisms.

Inventive Principle:
Principle #15Dynamics

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 achieves efficient circular polarization with low insertion losses and grating lobe resistance, allowing for a wide bandwidth and reduced beam tilting, effectively addressing the limitations of prior antennas in dual polarization and beam steering.

Implementation Method 1

A slot antenna according to claim 1 and, respectively, a method for operating an antenna, according to claim 15

Methodology Applied
Scientific EffectWaveguide: Waveguide

Implementation Method 2

with at least one slot constructed in a broadwall of the waveguide for emitting an electromagnetic wave

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

the slot is surrounded on the exterior side of the waveguide by an arrangement for rotating the polarization direction of the electromagnetic wave emitted by the slot itself

Methodology Applied
Scientific EffectPolarization rotation: Polarisation

Data Source

PatentEP2245704B1Slot antenna and method for operating the same
Publication Date: 2015.02.18 SELEX ES
  • EP2245704B1 patent drawingFigure 1~2
  • EP2245704B1 patent drawingFigure 3
  • EP2245704B1 patent drawingFigure 4

AI summary

A slot antenna having a single -ridge waveguide (13) with a top broadwall (12) and a plurality of radiant elements (5). The radiant elements are formed on the top broadwall (12) and are configured to radiate and receive circularly- polarized waves. Each radiant element (5) is formed by two slots (11) which are arranged at 90 to each other, are non-overlapping, extend on opposite sides with respect of the broadwall axis A and are spaced apart from each other by a mutual distance in the range of lambdag/4±20%, wherein lambdag is a nominal guide wavelength.