Patch Antenna Ground Layer Shaping for Under-Radar Detection

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Solution Overview

Problem

Conventional patch antenna arrays used in high-frequency radars have limited or no ability to detect objects or presence under the radar due to their high gain, which results in a weak or no signal in the end-fire direction, limiting their detection capabilities.

Innovation Solution

A patch antenna design with a modified ground layer that generates a radiation pattern with a sub-beam directed parallel to the antenna aperture, allowing for energy transmission or reception under the antenna, achieved by configuring the ground layer to be shorter than the dielectric substrate and introducing distortion through cut-outs or shape modifications near the bottom edge, enabling detection of objects or presence under the radar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional patch antenna arrays are used with high antenna gain, then long radar range is achieved, but detection capability under the radar is limited or lost

Engineering Contradiction:
Improveantenna gainVSAvoiddetection capability under radar
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The ground layer is designed with non-uniform characteristics - specifically with cutouts or gaps at specific locations - to create localized radiation patterns that differ from the uniform high-gain pattern. This allows different regions of the antenna to serve different functions: maintaining high gain in the boresight direction while creating end-fire beams for under-radar detection

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The ground layer is segmented by introducing cutouts or gaps, dividing it into multiple sections. This segmentation disrupts the uniform current distribution and creates multiple radiation paths, enabling the antenna to generate both the main boresight beam and additional end-fire beams for under-radar detection

Inventive Principle:
Principle #1Segmentation

2Power

If high antenna gain is used, then long radar range is achieved, but signal strength under the antenna becomes weak or non-existent

Engineering Contradiction:
Improveantenna gainVSAvoidradiated energy distribution
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The ground layer incorporates localized modifications (cutouts, gaps, or shape changes) at specific positions to alter the current distribution and radiation pattern in targeted directions. These local changes enable energy to be directed both forward (boresight) and downward (end-fire) without requiring a complete redesign of the entire antenna structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The dimensions, shape, or configuration of the ground layer are modified to change the radiation characteristics. By adjusting parameters such as ground layer length, width, cutout size, or gap position, the antenna can control the distribution of radiated energy to achieve both high gain and under-radar detection capability

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

The modified radiation pattern extends the field of view and provides radiation power in the end-fire direction without compromising the boresight radiation and range, effectively enhancing the radar's ability to detect presence under the sensor.

Implementation Method 1

a radiating microstrip patch element with ground layer wherein the ground layer is configured such that a radiation pattern of the patch antenna comprises a beam perpendicular to an antenna aperture, and a sub-beam parallel to the antenna aperture

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

The ground layer may comprise one or more cut-outs near a bottom edge of the ground layer, the one or more cut-outs may be configured to generate distortion in the radiation pattern

Methodology Applied
Scientific EffectElectromagnetic wave distortion: Diffraction

Data Source

PatentEP4329094A1Modified radar antenna array
Publication Date: 2024.02.28 CARRIER CORP
  • EP4329094A1 patent drawingFigure 1A~1B
  • EP4329094A1 patent drawingFigure 1C~1D
  • EP4329094A1 patent drawingFigure 2A~2C

AI summary

A patch antenna (100) comprises a radiating microstrip patch element (120); and a ground layer (140) electromagnetically connected to the patch element (120), wherein the ground layer (140) is configured such that a radiation pattern of the patch antenna (100) comprises a beam perpendicular to the antenna aperture, and a sub-beam parallel to the antenna aperture.