**Meet the editor**

Dr. Kishk is a Professor at Concordia University, Canada and Canada Research Chair in Advanced Antenna Systems. He is an Editor of Antennas & Propagation Magazine. His research interest in the areas of electromagnetics, dielectric resonator antennas, printed antennas, RFID antennas for readers and tags, Multi-function antennas, microwave circuits, EBG, artificial magnetic

conductors, soft/hard surfaces, phased array antennas, and computer aided design for antennas. He has published over 230-refereed Journal articles and 380 conference papers. He is a coauthor of four books and several book chapters and editor of one book. He offered several short courses in international conferences. He is a recipient of several awards. Two papers received outstanding paper awards from the Applied Computational Electromagnetic Society Journal. In addition, he received the 2004 Microwave Theory and Techniques Society Microwave Prize. Kishk is a Fellow of IEEE, Fellow of Electromagnetic Academy, and Fellow of Applied Computational Electromagnetic Society.

Contents

**Preface VII**

**Section 1 Design Techniques 1**

**Their Arrays 3**

**Patch Antenna 33**

Ouarda Barkat

**Section 2 Multiband Planar Antennas 73**

**Applications 75**

**Array Design 99**

**Section 3 UWB Printed Antennas 123**

Shun-Shi Zhong and Zhu Sun

Chapter 6 **UWB Antennas for Wireless Applications 125** Osama Haraz and Abdel-Razik Sebak

Marek Bugaj and Marian Wnuk

Chapter 1 **Design Techniques for Conformal Microstrip Antennas and**

Chapter 2 **Bandwidth Optimization of Aperture-Coupled Stacked**

Chapter 3 **Full-Wave Spectral Analysis of Resonant Characteristics and**

Chapter 5 **Shared-Aperture Multi-Band Dual-Polarized SAR Microstrip**

**Annular Ring Microstrip Antennas 57**

Chapter 4 **Compact Planar Multiband Antennas for Mobile**

Daniel B. Ferreira, Cristiano B. de Paula and Daniel C. Nascimento

**Radiation Patterns of High Tc Superconducting Circular and**

Ahmad Rashidy Razali, Amin M Abbosh and Marco A Antoniades

### Contents




**X** Contents



Preface

reached beyond what were thought impossible.

strip antenna design advancements.

The Topic of microstrip antennas is an old subject that started over 40 years ago. Microstrip antennas are low profile and easily fabricated. This subject has passed through several stages that make it survive tell now and still in continues progress. The main stage is the development of low loss low cost dielectric materials that make it possible to design an effi‐ cient low profile microstrip patches. The stage of developing analysis methods and models that helped in the design of radiating patches with simple shapes such as the transmission line model and cavity model. These simple models have also been modified to reach to more realistic designs that produce results close to the measured results for thin dielectric sub‐ strates. With the strive and advancements of computer capabilities in terms of memory and speed, numerical techniques suitable for the multilayer structure allowed for more accurate of more complicated microstrip antennas based on full wave analysis. Numerical techniques released the designer from using simple patch shapes. As the numerical techniques became more and more affordable and sophisticated many of the constraints related to the substrate thickness are removed to allow for thick and multilayers to increase the bandwidth as well as using different excitation mechanisms. With the advancement in the three dimensional analysis of finite structures a new horizon has opened to help the designer in reaching more and more realistic designs that are exact modeling of the real antennas with details that might even been not related to the electromagnetic effects. These techniques did not stop to the point of only designing the antenna that operates in free space, but extended to include the interaction effects with the surrounding medium such as the human body for wireless applications. The advancements of the computational techniques and the computational fa‐ cilities helped the designer to think out of the box and reach to designs that have actually

Microstrip advancements have strived when they were required to meet new specifications for new applications with new challenges. Microstrip antennas have become increasingly useful in telecommunications, automotive, aerospace, and biomedical applications. Advan‐ ces in this technology were originally driven by the defense sector but have now been ex‐ panded to many commercial applications. Global positioning satellites and wide area communication networks are just a few of the technologies that have benefitted from micro‐

The book discusses basic and advanced concepts of microstrip antennas, including design procedure and recent applications. Book topics include discussion of arrays, spectral domain, high Tc superconducting microstrip antennas, optimization, multiband, dual and circular po‐ larization, microstrip to waveguide transitions, and improving bandwidth and resonance fre‐ quency. Antenna synthesis, materials, microstrip circuits, spectral domain, waveform evaluation, aperture coupled antenna geometry and miniaturization are further book topics.


### Preface

Chapter 7 **Printed Wide Slot Ultra-Wideband Antenna 153** Rezaul Azim and Mohammad Tariqul Islam

Chapter 8 **Recent Trends in Printed Ultra-Wideband (UWB)**

**Diversity Applications 203**

**Microstrip Antenna 229**

**Section 5 Recent Advanced Applications 247**

Chapter 10 **Axial Ratio Bandwidth of a Circularly Polarized**

Chapter 11 **Planar Microstrip-To-Waveguide Transition in Millimeter-Wave Band 249**

Li Sun, Gang Ou, Yilong Lu and Shusen Tan

Chapter 12 **Drooped Microstrip Antennas for GPS Marine and Aerospace**

Chapter 14 **Reconfigurable Microstrip Antennas for Cognitive Radio 337**

Chapter 15 **Design, Fabrication, and Testing of Flexible Antennas 363**

Ken G. Clark, Hussain M. Al-Rizzo, James M. Tranquilla, Haider

Mohammed Al-Husseini, Karim Y. Kabalan, Ali El-Hajj and Christos

Haider R. Khaleel, Hussain M. Al-Rizzo and Ayman I. Abbosh

Mohammad Tariqul Islam and Rezaul Azim

Chapter 9 **Dual Port Ultra Wideband Antennas for Cognitive Radio and**

Gijo Augustin , Bybi P. Chacko and Tayeb A. Denidni

**Antennas 173**

**VI** Contents

**Section 4 Circular Polarization 227**

Kazuyuki Seo

**Navigation 279**

Albert Sabban

G. Christodoulou

Khaleel and Ayman Abbosh

Chapter 13 **Wearable Antennas for Medical Applications 305**

The Topic of microstrip antennas is an old subject that started over 40 years ago. Microstrip antennas are low profile and easily fabricated. This subject has passed through several stages that make it survive tell now and still in continues progress. The main stage is the development of low loss low cost dielectric materials that make it possible to design an effi‐ cient low profile microstrip patches. The stage of developing analysis methods and models that helped in the design of radiating patches with simple shapes such as the transmission line model and cavity model. These simple models have also been modified to reach to more realistic designs that produce results close to the measured results for thin dielectric sub‐ strates. With the strive and advancements of computer capabilities in terms of memory and speed, numerical techniques suitable for the multilayer structure allowed for more accurate of more complicated microstrip antennas based on full wave analysis. Numerical techniques released the designer from using simple patch shapes. As the numerical techniques became more and more affordable and sophisticated many of the constraints related to the substrate thickness are removed to allow for thick and multilayers to increase the bandwidth as well as using different excitation mechanisms. With the advancement in the three dimensional analysis of finite structures a new horizon has opened to help the designer in reaching more and more realistic designs that are exact modeling of the real antennas with details that might even been not related to the electromagnetic effects. These techniques did not stop to the point of only designing the antenna that operates in free space, but extended to include the interaction effects with the surrounding medium such as the human body for wireless applications. The advancements of the computational techniques and the computational fa‐ cilities helped the designer to think out of the box and reach to designs that have actually reached beyond what were thought impossible.

Microstrip advancements have strived when they were required to meet new specifications for new applications with new challenges. Microstrip antennas have become increasingly useful in telecommunications, automotive, aerospace, and biomedical applications. Advan‐ ces in this technology were originally driven by the defense sector but have now been ex‐ panded to many commercial applications. Global positioning satellites and wide area communication networks are just a few of the technologies that have benefitted from micro‐ strip antenna design advancements.

The book discusses basic and advanced concepts of microstrip antennas, including design procedure and recent applications. Book topics include discussion of arrays, spectral domain, high Tc superconducting microstrip antennas, optimization, multiband, dual and circular po‐ larization, microstrip to waveguide transitions, and improving bandwidth and resonance fre‐ quency. Antenna synthesis, materials, microstrip circuits, spectral domain, waveform evaluation, aperture coupled antenna geometry and miniaturization are further book topics.

Planar UWB antennas are widely covered and new dual polarized UWB antennas are newly introduced. Design of UWB antennas with single or multi notch bands are also considered. Recent applications such as, cognitive radio, reconfigurable antennas, wearable antennas, and flexible antennas are presented. The book audience will be comprised of electrical and com‐ puter engineers and other scientists well versed in microstrip antenna technology.

At the same time, we will provide some quantitative guidelines for designing those types of UWB antennas. A novel method for the design of a UWB planar antenna with band-notch characteristics is presented. Parasitic elements in the form of printed strips are placed in the radiating aperture of the planar antenna at the top and bottom layer to suppress the radia‐ tion at certain frequencies within the UWB band. The parasitic elements have dimensions,

Preface IX

In Chapter 7, a compact tapered shape wide slot antenna is designed UWB application. The antenna consists of wide slot of tapered shape and microstrip line-fed rectangular tuning stub. The measured results show that the antenna achieves good impedance matching, con‐ stant gain, and stable radiation patterns over an operating. The stable Omni-directional radi‐ ation pattern and flat group delay makes the proposed antenna suitable for being used in

In chapter 8, rectangular planar antenna is initially chosen as conventional structure due to its low profile and ease of fabrication. A technique, reducing the size of the ground plane and cutting of different slots is applied to reduce the ground plane dependency. It also show that shortening of current path by removal of the upper portion of the ground plane and insertion of the slots contributes to the wider bandwidth at the low frequency end. Studies indicate that the rectangular antenna with modified sawtooth shape ground plane is capable of supporting closely spaced multiple resonant modes and overlapping of these resonances leads to the UWB characteristic. It is observed that the cutting triangular shape slots on the ground plane help to increase the bandwidth. Moreover, it exhibits stable radiation patterns

In chapter 9, a compact uniplanar dual polarized UWB antenna with notch functionality is developed for diversity applications. The antenna features a 2:1 VSWR band from 2.8-11 GHz while showing the rejection performance in the frequency band 4.99-6.25 GHz along with a reasonable isolation better than 15dB. The measured radiation pattern and the envel‐ op correlation coefficient indicate that the antenna provides good polarization diversity per‐ formance. Time domain analysis of the antenna shows faithful reproduction of the

Chapter 10 introduces the basic methods, which can form the circular polarization (CP) for a microstrip antenna, including the single-feed and the multiple-feed. When using multiplefeed for one patch, sequential rotation technology further improved the CP bandwidth. The theoretical computation of the axial ratio bandwidth of a multiple-feed microstrip antenna is provided. The more feeds, the better the axial ratio bandwidth. The detail analysis of axial ratio bandwidth including the effect of the amplitudes with some difference and the phase excitation of the feed point has an offset according to the designed central frequency in man‐

Chapter 11 presents the design of a microstrip transition to a rectangular waveguide. The shape of the microstrip patch element of the transition, which contributes coupling to the microstrip line is focused as an important structure. By modification of the shape of the patch element, current on the patch element is controlled and various new functions of the transitions are investigated and proposed. Four novel microstrip-to-waveguide transitions are demonstrated; broadband microstrip-to-waveguide transition using waveguide with large broad-wall, narrow-wall-connected microstrip-to-waveguide transition, transition from waveguide to two microstrip lines with slot radiators and microstrip-to-waveguide

with satisfactory gain, radiation efficiency and good time domain behavior.

which are chosen according to a certain formula.

transmitted pulse even with a notch band.

ufacture are described.

UWB applications.

Chapter 1 presents new design techniques for conformal microstrip antennas and their ar‐ rays that can affect significant reductions in design time and improvements in design accu‐ racy. The proposed algorithm for designing conformal microstrip antennas employs an adaptive transmission line model for probe positioning through circuital simulation, whose parameters are derived from the output data determined after the radiator analysis in a fullwave electromagnetic simulator. Its advantages are pointed out through the design of probe-fed cylindrical, spherical and conical microstrip antennas with quasi-rectangular patches. A procedure for synthesizing the radiation pattern of conformal microstrip anten‐ nas based on the iterative solution of linearly constrained least squares problems and takes into account the radiation pattern of each array element is addressed. To complete the arrays design, an active feed network, suitable for tracking systems and composed of phase shifters and variable gain amplifiers, is presented. A computationally-efficient CAD, which incorpo‐ rates the design technique for conformal microstrip arrays, is also described.

Chapter 2 presents techniques to increase the bandwidth of multilayer planar antennas fed by slots. This configuration has many advantages, including wide bandwidth, reduction in spurious feed network radiation, and a symmetric radiation pattern with low cross-polariza‐ tion. The antenna configuration with a resonant aperture yields wide bandwidth by proper optimization of the coupling between the patch and the resonant slot. The basic characteris‐ tics and the effects of various parameters on the overall antenna performance are discussed.

Chapter 3 studies of the high Tc superconducting microstrip antennas. Various patch config‐ urations implemented on different types of substrates are tested and investigated. The com‐ plex resonant frequency problem of structure is formulated in terms of an integral equation. The effect of a superconductor microstrip patch, the surface complex impedance is consid‐ ered. The superconductor patch thickness and the temperature have significant effect on the resonant frequency of the antenna.

Chapter 4 presents designs of compact planar multiband antennas for mobile and portable wireless devices. Miniaturization techniques such as meandering, bending, folding and wrapping are used, while multiband operation is generated from ground plane modifica‐ tions using fixed slots, reconfigurable slots, and a ground strip. All the designs utilize their ground planes to achieve multiband operation. All the presented design models lead to promising configurations for application in wireless services.

Chapter 5 introduces the design of a shared-aperture multi-band dual-polarized (MBDP) microstrip array for SAR applications. It operates at X-, S- and L- bands with a frequency ratio of 8:2.8:1. This shared-aperture L/S/X MBDP array composes of L/S and L/X dual-band dual-polarized (DBDP) shared-aperture sub-arrays and an L-band dual-polarized (DP) subarray. The radiation patterns at each band show cross-polarization level lower than -30dB within the main lobe region and the scanning view.

Chapter 6 presents different UWB planar monopole antennas to illustrate different features in their operations and seeking for the best candidate for UWB communication applications.

At the same time, we will provide some quantitative guidelines for designing those types of UWB antennas. A novel method for the design of a UWB planar antenna with band-notch characteristics is presented. Parasitic elements in the form of printed strips are placed in the radiating aperture of the planar antenna at the top and bottom layer to suppress the radia‐ tion at certain frequencies within the UWB band. The parasitic elements have dimensions, which are chosen according to a certain formula.

Planar UWB antennas are widely covered and new dual polarized UWB antennas are newly introduced. Design of UWB antennas with single or multi notch bands are also considered. Recent applications such as, cognitive radio, reconfigurable antennas, wearable antennas, and flexible antennas are presented. The book audience will be comprised of electrical and com‐

Chapter 1 presents new design techniques for conformal microstrip antennas and their ar‐ rays that can affect significant reductions in design time and improvements in design accu‐ racy. The proposed algorithm for designing conformal microstrip antennas employs an adaptive transmission line model for probe positioning through circuital simulation, whose parameters are derived from the output data determined after the radiator analysis in a fullwave electromagnetic simulator. Its advantages are pointed out through the design of probe-fed cylindrical, spherical and conical microstrip antennas with quasi-rectangular patches. A procedure for synthesizing the radiation pattern of conformal microstrip anten‐ nas based on the iterative solution of linearly constrained least squares problems and takes into account the radiation pattern of each array element is addressed. To complete the arrays design, an active feed network, suitable for tracking systems and composed of phase shifters and variable gain amplifiers, is presented. A computationally-efficient CAD, which incorpo‐

Chapter 2 presents techniques to increase the bandwidth of multilayer planar antennas fed by slots. This configuration has many advantages, including wide bandwidth, reduction in spurious feed network radiation, and a symmetric radiation pattern with low cross-polariza‐ tion. The antenna configuration with a resonant aperture yields wide bandwidth by proper optimization of the coupling between the patch and the resonant slot. The basic characteris‐ tics and the effects of various parameters on the overall antenna performance are discussed. Chapter 3 studies of the high Tc superconducting microstrip antennas. Various patch config‐ urations implemented on different types of substrates are tested and investigated. The com‐ plex resonant frequency problem of structure is formulated in terms of an integral equation. The effect of a superconductor microstrip patch, the surface complex impedance is consid‐ ered. The superconductor patch thickness and the temperature have significant effect on the

Chapter 4 presents designs of compact planar multiband antennas for mobile and portable wireless devices. Miniaturization techniques such as meandering, bending, folding and wrapping are used, while multiband operation is generated from ground plane modifica‐ tions using fixed slots, reconfigurable slots, and a ground strip. All the designs utilize their ground planes to achieve multiband operation. All the presented design models lead to

Chapter 5 introduces the design of a shared-aperture multi-band dual-polarized (MBDP) microstrip array for SAR applications. It operates at X-, S- and L- bands with a frequency ratio of 8:2.8:1. This shared-aperture L/S/X MBDP array composes of L/S and L/X dual-band dual-polarized (DBDP) shared-aperture sub-arrays and an L-band dual-polarized (DP) subarray. The radiation patterns at each band show cross-polarization level lower than -30dB

Chapter 6 presents different UWB planar monopole antennas to illustrate different features in their operations and seeking for the best candidate for UWB communication applications.

puter engineers and other scientists well versed in microstrip antenna technology.

rates the design technique for conformal microstrip arrays, is also described.

resonant frequency of the antenna.

VIII Preface

promising configurations for application in wireless services.

within the main lobe region and the scanning view.

In Chapter 7, a compact tapered shape wide slot antenna is designed UWB application. The antenna consists of wide slot of tapered shape and microstrip line-fed rectangular tuning stub. The measured results show that the antenna achieves good impedance matching, con‐ stant gain, and stable radiation patterns over an operating. The stable Omni-directional radi‐ ation pattern and flat group delay makes the proposed antenna suitable for being used in UWB applications.

In chapter 8, rectangular planar antenna is initially chosen as conventional structure due to its low profile and ease of fabrication. A technique, reducing the size of the ground plane and cutting of different slots is applied to reduce the ground plane dependency. It also show that shortening of current path by removal of the upper portion of the ground plane and insertion of the slots contributes to the wider bandwidth at the low frequency end. Studies indicate that the rectangular antenna with modified sawtooth shape ground plane is capable of supporting closely spaced multiple resonant modes and overlapping of these resonances leads to the UWB characteristic. It is observed that the cutting triangular shape slots on the ground plane help to increase the bandwidth. Moreover, it exhibits stable radiation patterns with satisfactory gain, radiation efficiency and good time domain behavior.

In chapter 9, a compact uniplanar dual polarized UWB antenna with notch functionality is developed for diversity applications. The antenna features a 2:1 VSWR band from 2.8-11 GHz while showing the rejection performance in the frequency band 4.99-6.25 GHz along with a reasonable isolation better than 15dB. The measured radiation pattern and the envel‐ op correlation coefficient indicate that the antenna provides good polarization diversity per‐ formance. Time domain analysis of the antenna shows faithful reproduction of the transmitted pulse even with a notch band.

Chapter 10 introduces the basic methods, which can form the circular polarization (CP) for a microstrip antenna, including the single-feed and the multiple-feed. When using multiplefeed for one patch, sequential rotation technology further improved the CP bandwidth. The theoretical computation of the axial ratio bandwidth of a multiple-feed microstrip antenna is provided. The more feeds, the better the axial ratio bandwidth. The detail analysis of axial ratio bandwidth including the effect of the amplitudes with some difference and the phase excitation of the feed point has an offset according to the designed central frequency in man‐ ufacture are described.

Chapter 11 presents the design of a microstrip transition to a rectangular waveguide. The shape of the microstrip patch element of the transition, which contributes coupling to the microstrip line is focused as an important structure. By modification of the shape of the patch element, current on the patch element is controlled and various new functions of the transitions are investigated and proposed. Four novel microstrip-to-waveguide transitions are demonstrated; broadband microstrip-to-waveguide transition using waveguide with large broad-wall, narrow-wall-connected microstrip-to-waveguide transition, transition from waveguide to two microstrip lines with slot radiators and microstrip-to-waveguide transition using no via holes. These transitions are designed and fabricated around 77 GHz and 79 GHz band.

In Chapter 12, design considerations, parametric analysis, and extensive performance charac‐ terizations are presented for microstrip antenna elements conformably mounted on truncated pyramidal ground planes. The drooped microstrip antennas are examined to explore the fea‐ sibility of controlling their radiation patterns for Global Positioning System (GPS) applica‐ tions involving a platform subjected to pitch and roll. Pattern shaping is achieved by varying the angle and position of the bend, length of the ground plane beyond the bend, as well as the thickness and permittivity of the substrate. A variety of downward and upward drooped geo‐ metries are assessed, based on their impact on gain at boresight, near horizon gain reduction, phase center stability, half power beamwidth, and polarization purity. It is demonstrated that stable phase response over the entire upper hemisphere, half-power beamwidths is better than the equivalent flat patch, and a wide range of radiation pattern shapes can be realized to suit applications involving GPS marine and aerospace navigation systems.

Chapter 13 presents several designs of wearable linearly and dually polarized antennas. The antenna may be used in Medicare RF systems. The antennas reflection coefficients for differ‐ ent belt thickness, shirt thickness and air spacing between the antennas and human body are presented. If the air spacing between the new dually polarized antenna and the human body is increased the antenna resonant frequency is shifted. Therefore, varactors are employed to tune the antennas resonant frequency.

Chapter 14 discusses the design of antennas for Cognitive Radio (CR) applications. UWB antennas are required for sensing in overlay CR, and for communicating in underlay CR. Modified UWB antennas with reconfigurable band notches allow to employ UWB technolo‐ gy in overlay CR and to achieve high-data-rate and long distances communications. Overlay CR requires reconfigurable wideband/narrowband antennas, to perform the two tasks of sensing a wide band and communicating over a narrow white space. UWB antennas with reconfigurable band rejections, and single-port/dual-port wide-narrowband and tunable an‐ tennas suitable for these approaches are reported.

In chapter 15, the design, fabrication process and methods, flexibility tests, and measure‐ ment of flexible antennas are discussed in details. To show the process by example, a print‐ ed monopole antenna designed at 2.45GHz, Industrial Scientific Medical (ISM) band, which has the merits of light weight, ultra-low profile, wide bandwidth, mechanical robustness, compactness, and high efficiency, is presented. The antenna is tested against bending effect to characterize. A comparison with different types of flexible antennas is reported in terms of size, robustness and electromagnetic performance is provided.

> **Ahmed Kishk** University of Mississippi, USA

**Section 1**

**Design Techniques**

**Section 1**

**Design Techniques**

transition using no via holes. These transitions are designed and fabricated around 77 GHz

In Chapter 12, design considerations, parametric analysis, and extensive performance charac‐ terizations are presented for microstrip antenna elements conformably mounted on truncated pyramidal ground planes. The drooped microstrip antennas are examined to explore the fea‐ sibility of controlling their radiation patterns for Global Positioning System (GPS) applica‐ tions involving a platform subjected to pitch and roll. Pattern shaping is achieved by varying the angle and position of the bend, length of the ground plane beyond the bend, as well as the thickness and permittivity of the substrate. A variety of downward and upward drooped geo‐ metries are assessed, based on their impact on gain at boresight, near horizon gain reduction, phase center stability, half power beamwidth, and polarization purity. It is demonstrated that stable phase response over the entire upper hemisphere, half-power beamwidths is better than the equivalent flat patch, and a wide range of radiation pattern shapes can be realized to

Chapter 13 presents several designs of wearable linearly and dually polarized antennas. The antenna may be used in Medicare RF systems. The antennas reflection coefficients for differ‐ ent belt thickness, shirt thickness and air spacing between the antennas and human body are presented. If the air spacing between the new dually polarized antenna and the human body is increased the antenna resonant frequency is shifted. Therefore, varactors are employed to

Chapter 14 discusses the design of antennas for Cognitive Radio (CR) applications. UWB antennas are required for sensing in overlay CR, and for communicating in underlay CR. Modified UWB antennas with reconfigurable band notches allow to employ UWB technolo‐ gy in overlay CR and to achieve high-data-rate and long distances communications. Overlay CR requires reconfigurable wideband/narrowband antennas, to perform the two tasks of sensing a wide band and communicating over a narrow white space. UWB antennas with reconfigurable band rejections, and single-port/dual-port wide-narrowband and tunable an‐

In chapter 15, the design, fabrication process and methods, flexibility tests, and measure‐ ment of flexible antennas are discussed in details. To show the process by example, a print‐ ed monopole antenna designed at 2.45GHz, Industrial Scientific Medical (ISM) band, which has the merits of light weight, ultra-low profile, wide bandwidth, mechanical robustness, compactness, and high efficiency, is presented. The antenna is tested against bending effect to characterize. A comparison with different types of flexible antennas is reported in terms

**Ahmed Kishk**

University of Mississippi, USA

suit applications involving GPS marine and aerospace navigation systems.

and 79 GHz band.

X Preface

tune the antennas resonant frequency.

tennas suitable for these approaches are reported.

of size, robustness and electromagnetic performance is provided.

**Chapter 1**

**Design Techniques for**

Daniel C. Nascimento

http://dx.doi.org/10.5772/53019

**1. Introduction**

Daniel B. Ferreira, Cristiano B. de Paula and

Additional information is available at the end of the chapter

things, significant reductions in design time.

**Conformal Microstrip Antennas and Their Arrays**

Owing to their electrical and mechanical attractive characteristics, conformal microstrip an‐ tennas and their arrays are suitable for installation in a wide variety of structures such as aircrafts, missiles, satellites, ships, vehicles, base stations, etc. Specifically, these radiators can become integrated with the structures where they are mounted on and, consequently, do not cause extra drag and are less visible to the human eye; moreover they are lowweight, easy to fabricate and can be integrated with microwave and millimetre-wave cir‐ cuits [1,2]. Nonetheless, there are few algorithms available in the literature to assist their design. The purpose of this chapter is to present accurate design techniques for conformal microstrip antennas and arrays composed of these radiators that can bring, among other

The development of efficient design techniques for conformal microstrip radiators, assist‐ ed by state-of-the-art computational electromagnetic tools, is desirable in order to estab‐ lish clear procedures that bring about reductions in computational time, along with high accuracy results. Nowadays, the commercial availability of high performance three-dimen‐ sional electromagnetic tools allows computer-aided analysis and optimization that replace the design process based on iterative experimental modification of the initial prototype. Software such as CST®, which uses the Finite Integration Technique (FIT), and HFSS®, based on the Finite Element Method (FEM), are two examples of analysis tools available in the market [3]. But, since they are only capable of performing the analysis of the struc‐ tures, the synthesis of an antenna needs to be guided by an algorithm whereby iterative

> © 2013 Ferreira et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 Ferreira et al.; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
