In this thesis, a PSO optimization algorithm is applied using a developed technique to synthesize the radiation patterns required for high-resolution land imaging SAR and satellite communications using planar rectangular or concentric circular arrays. The goal of the PSO algorithm is to get the excitation coefficients of the array elements, which are, then, Microstrip patch antennas with linear or circular polarization are proposed to construct the synthesized-beam arrays required for the considered application.

A wide band rectangular patch antenna with U-slot is proposed for planar arrays with linear polarization. A square patch antenna with four truncated corners and four axial slots is designed for planar rectangular and circular arrays. Finally, a square patch antenna with two L-shaped slots inserted at diagonally opposite corners is designed for planar concentric circular arrays. Turnstile arrays of either dipole elements or U-slotted microstrip patch antennas excited with circulating phase shift are proposed to construct planar arrays with circular polarization for land-imaging SAR systems and satellite communications.

Synthetic Aperture Radar (SAR) is used for remote sensing to create two-dimensional images of land covers on the earth’s surface. Such a land-imaging system has a great importance in many civilian and military applications. The SAR uses the radar antenna to scan a ground area to provide microwave images with fine spatial resolution. The SAR is typically mounted on an aircraft or spacecraft, and usually has a form of side-looking radar. It uses the Doppler and time delay information of the ground reflected wave to generate a two-dimensional image with the desired azimuth resolution (direction of motion) and range resolution (normal to the direction of motion), respectively.

The SAR operation requires a physical antenna of radiation pattern with foot print of high aspect ratio and a mechanism capable of achieving beam steering and beam shaping. The SAR antenna array should be rigid, planar, deployable, and as lightweight as possible. A side-looking SAR system requires an antenna with a flat-topped beam pattern in the plane of the azimuth direction and a cosecant-squared beam shape in the plane of the range direction. For satellite communications with the ground stations, an isoflux beam is required for uniform coverage and continuity during the communication session.

Extrait

Inhaltsverzeichnis (Table of Contents)

Chapter 1 :Introduction

1.1. An Overview
1.2 Organization of the Thesis

Chapter 2: Antenna Arrays for Land-Imaging SAR Systems Application Requirements and Methods of Beam Shaping

2.1 Introduction
2.2 Electromagnetic Wave Polarization

2.2.1 Elliptically Polarized Fields

2.2.1.1 Polarization Ellipse

2.2.2 Linearly Polarized Fields
2.2.3 Vertical and Horizontal Polarizations for Polarimetric SAR Systems
2.2.4 Circularly Polarized Fields

2.2.4.1 Simple Method to Produce Circular Polarization

2.3 Atmospheric Propagation Impairments of Land-Imaging SAR

2.3.1 Effect of the Ionosphere
2.3.2 Effect of the Troposphere

2.4 Operation of the Side-Looking SAR System

2.4.1. Range Resolution in Case of Uncompressed Pulse
2.4.2. Azimuth Resolution
2.4.3 Simplified Calculation Of The Pulse Reptition Interval
2.4.4. Pulse Compression using Linear Frequency Modulation (LFM)

2.5. Requirements of Polarimetric SAR Antenna Arrays

2.5.1. Operational Frequency Bands for Commercial Land-Imaging SAR Systems
2.5.2 Requirements of Antenna Arrays for Land Imaging
2.5.3 Requirements of Antenna Arrays for Image Download to Ground Stations

2.6. Antenna Arrays for Commercial Space-Borne Land-Imaging SAR Systems

2.6.1 Antenna Array of the Spaceborne ‘RADARSAT-2’ SAR System
2.6.2 Antenna Array of the Spaceborne ‘SEOSAR/PAZ’ SAR System
2.6.3. Circularly Polarized PolSAR Antenna Arrays Proposed for Land Imaging
2.6.4. Antenna Arrays for PolSAR Image Data Download to Ground Stations

2.7 Beam Shapes for Spaceborne SAR and Satellite communications

2.7.1 Beam Shape for Isoflux Radiation from LEO Satellites
2.7.2 Cosecant-Squared Beam
2.7.3 Flat-Topped Beam

2.8 Optimization Techniques for Antenna Array Pattern Synthesis

2.8.1 PSO for Antenna Array Pattern Synthesis

2.8.1.1 Iterative Algorithm for the PSO

Chapter 3: Microstrip Patch Antennas for SAR Arrays and Satellite Communications

3.1. Introduction
3.2 Design of Rectangular Microstrip Patch Antenna

3.2.1 Linearly Polarized Microstrip Patch Antenna
3.2.2 Circularly Polarized Microstrip Patch Antenna

3.3 Wide Band U-Slotted Rectangular Patch Antenna for Linear Polarization

3.3.1 U-Slotted Patch Antenna Fed by Straight Probe
3.3.2 U-Slotted Patch Antenna fed by an L-shaped Probe

3.4 Truncated-Corner Microstrip Square Patch Antenna for Circular Polarization

3.4.1 Mechanism of Producing Circular Polarization for truncated corner
3.4.2 Controlling the sense of polarization

3.5 Corner-Slotted Microstrip Square Patch Antenna for Circular Polarization

3.5.1 The Mechanism of Producing Circular Polarization for the corner slotted

3.6 Compact Dual Band Dual Polarized Square Microstrip Antenna
3.7 Mutual Coupling between Microstrip Patch Antennas

3.7.1 Mutual Coupling between U-Slotted Patch Antennas
3.7.2 Mutual Coupling between Truncated-Corner Patch Antennas

3.8 Results and Discussions

3.8.1 U-Slotted Patch Antenna over Foam Substrate

3.8.1.1 U-Slotted patch antenna over foam substrate fed by a straight probe
3.8.1.2 U-Slotted patch antenna over foam substrate fed by the L-shaped probe

3.8.2 U-Slotted patch Antenna over FR4 Substrate
3.8.3 Truncated-Corners Microstrip Patch Antenna

3.8.3.1 Current distribution on the surface of a microstrip patch
3.8.3.2 Frequency band of the truncated-corners patch antenna
3.8.3.3 Experimental assessment of the truncated-corners patch antenna
3.8.3.4 Radiation patterns of the circularly polarized fields for the truncated-corners patch

3.8.4 Corner-Slotted Microstrip Patch Antenna

3.8.4.1 Frequency band of operation of the corner-slotted patch antenna
3.8.4.2 Radiation patterns of the circularly polarized fields for the corner-slotted patch antenna
3.8.4.3 Dimensional parametric studies for the corner-slotted antenna

3.8.5 Compact Dual Band Dual Polarized Square Microstrip Antenna

3.8.5.1 Frequency band of operation of the corner-slotted dual band dual polarized patch antenna
3.8.5.2 Radiation patterns of the dual polarized fields for the dual-fed corner-slotted patch antenna
3.8.5.3 Dimensional Parametric study for the dual-polarized patch antenna

3.8.6 Mutual Coupling between Microstrip Patch Antennas

3.8.6.1 Mutual coupling between adjacent U-slotted patch antennas
3.8.6.2 Investigation of adjacent Circularly Polarized Truncated-Corners Patch Antennas

Chapter 4: Shaped Beam Linear Arrays for High Resolution SAR and Satellite Communications

4.1. Introduction
4.2 Radiation Pattern of the Linear Array
4.3 PSO Algorithm for Beam Shaping using Linear Arrays of Point Sources
4.4 Numerical Results and Discussions

4.4.1 Application of PSO to Synthesize Beams for SAR and Satellite Communications

4.4.1.1 Flat-topped Beam Synthesized by Linear Arrays of Point Sources
4.4.1.2 Isoflux Beam Synthesized by Linear Arrays of Point Sources
4.4.1.3 Cosecant-Squared Beam Synthesized by Linear Arrays of Point Sources
4.4.1.4 Summary of the excitation coefficients distributed over the linear array elements to produce flat-topped, isoflux and cosecant-squared beams

4.4.2 Effect of the Linear Array Dimensions and Optimization Parameters on the Accuracy of the Synthesized Beam

4.4.2.1 Effect of the Inter-Element Separation
4.4.2.2 Effect of the Number of Elements
4.4.2.3 Effect of the Weighting Coefficients of the Cost Function

4.4.4 Beam Shaping using Linear Arrays of U-Slotted Microstrip Patches

4.4.4.1 Isoflux beam for uniform coverage by GEO satellite using a linear array of U-slotted patches on foam substrate
4.4.4.2 Isoflux beam for uniform coverage by LEO satellite using a linear array of U-slotted patches on foam substrate
4.4.4.3 Linear Arrays of U-Slotted Patches for Flat-Topped Beam
4.4.4.4 Linear Arrays of U-Slotted Patches for Cosecant-Squared Beam

4.4.5 Beam Shaping Using Linear Arrays of Circularly Polarized Patch Antennas

4.4.5.1 Cosecant-squared shaped beam
4.4.5.2 Flat-top shaped radiation pattern

Chapter 5: Shaped Beam Planar Arrays for High Resolution Land-Imaging SAR Systems

5.1 Introduction
5.2 Application of the PSO Algorithm to Planar Arrays
5.3 Results and Discussions

5.3.1 Three-Dimensional Beam Synthesis using Planar Arrays for side-looking SAR systems
5.3.2 Planar Arrays of Linearly Polarized Patch Antennas for Side-Looking SAR System
5.3.3 Planar Arrays of Circularly Polarized Patch Antennas for Side-Looking SAR System
5.3.4 Planar Arrays of Dual-polarized Patch Antennas for Side-Looking SAR System

Chapter 6

6.1. Introduction
6.2 Turnstile Antennas for Circular Polarization

6.2.1 Four-Dipole Turnstile Antenna in Free Space
6.2.2 Four-Dipole Turnstile Antenna above Ground Plane
6.2.3 Four patch Turnstile Antenna for Circular Polarization

6.3 Linear Arrays of Overlapped Turnstiles for Shaped Beam with Circular Polarization

6.3.1 The Linear Array of Two Overlapped Four-Dipole Turnstiles in Free Space
6.3.2 Linear Array of Four-Dipole Turnstiles in Free Space
6.3.3 Linear Arrays of Four-Dipole Turnstiles above Conducting Plate
6.3.4 Two Overlapped Turnstiles of Four U-slot patches
6.3.5 Linear Arrays of Overlapped Turnstiles of U-slotted patches

6.4 Planar Arrays of Turnstile Subarrays for Shaped Beam with Circular Polarization
6.5 Results and Discussions

6.5.1 Four-Dipole Turnstile Antenna
6.5.2 Effect of The Turnstile Array Radius on the Radiation Characteristics
6.5.3 Four-Dipole Turnstile above a Conducting Plate
6.5.4 Turnstile of Four U-slotted Patch Antennas
6.5.5 Two-Element Array of overlapped Four Dipole Turnstiles
6.5.6 Two-Element Array of Overlapped Turnstiles of Four U-slotted patches
6.5.7 Linear Array of Overlapped Four Dipole Turnstiles
6.5.8 Linear Array of Four-Dipole Turnstile Subarrays above a Conducting Reflector
6.5.9 Linear Arrays of overlapped Turnstiles of U-slotted patches

6.6 Planar Array of overlapped Turnstiles of Four Dipoles for Circular Polarization

6.6.1 Isoflux Shaped Beam
6.6.2 Cosecant Squared/Flat-topped Beam for Side looking SAR

6.7 Planar Arrays of overlapped Turnstiles of U-slotted Patches for Shaped Beam with Circular Polarization

Chapter 7: Shaped Beam Antenna Arrays with Circular Polarization for Land-Imaging SAR

7.1. Introduction
7.2 Circular Arrays of Printed Antennas
7.3 Radiation Pattern of Concentric Circular Arrays

7.3.1 Radiation Pattern of A Circular Array
7.3.2 Radiation Pattern of Multiple Concentric Circular Arrays
7.3.3 Concentric Circular Arrays for Circularly Symmetric Radiation Pattern

7.4 Application of PSO for Shaping the Beam of Circular Arrays

7.4.1 Application of the PSO to A Circular Array
7.4.2 Application of the PSO to Multiple Concentric Circular Arrays

7.5 Results and Discussions

7.5.1 Circular Array of Truncated-Corner Microstrip Patches for Directive Beam with Circular Polarization

7.5.1.1 Circular Arrays of Truncated–Corner Patch Antenna Elements for High Gain and Circular Polarization
7.5.1.2 Beamforming using A Circular Array

7.5.2 Concentric Circular Arrays for Flat-Topped Beam with Circular Polarization

7.5.2.1 Flat-Topped Beam by Concentric Circular Arrays of Isotropic Point Sources
7.5.2.2 Concentric Circular Arrays of Truncated-Corners Microstrip Patches for Flat-Topped Beam with Circular Polarization

7.6.3 Concentric Circular Arrays for Isoflux Beam with Circular Polarization

7.6.3.1 Isoflux Beam Synthesized by Concentric Circular Arrays of Point Source Elements
7.6.3.2 Concentric Circular Arrays of Corner-Slotted Microstrip Patches for Isoflux Beam with Circular Polarization

Chapter 8:Conclusions and Suggestions for Future Work

8.1 Conclusions
8.2 Future Work

Fin de l'extrait de 270 pages - haut de page

Résumé des informations

Titre: Wide Band Antenna Array for Synthetic Aperture Radar Applications
Auteur: Dr May Abo Elhassan (Auteur)
Année de publication: 2020
Pages: 270
N° de catalogue: V1245808
ISBN (PDF): 9783346675286
ISBN (Livre): 9783346675293
Langue: anglais
mots-clé: wide band antenna array synthetic aperture radar applications
Sécurité des produits: GRIN Publishing GmbH

Citation du texte: Dr May Abo Elhassan (Auteur), 2020, Wide Band Antenna Array for Synthetic Aperture Radar Applications, Munich, GRIN Verlag, https://www.grin.com/document/1245808

Wide Band Antenna Array for Synthetic Aperture Radar Applications

Extrait

Inhaltsverzeichnis (Table of Contents)

Résumé des informations