Advancess in Patch Antenena design Using EBG Structures

Abstract

High-performance applications in wireless communication systems require an advanced form of electromagnetic materials. The development of “metamaterials” with unique features has recently gained great attention from the researchers [1]. Metamaterials are used in many fields such as optics, nanoscience, material science, CONTENTS 11.1 Introduction ................................................................................................ 363 11.2 EBG Structures and Their Properties .........................................................364 11.3 EBG Structures in Patch Antenna Design ..................................................365 11.3.1 Bandwidth Improvement in Patch Antennas Using EBG Structures ...................................................................366 11.3.2 Gain Improvement Using EBG Structures ....................................368 11.3.3 Mutual Coupling Reduction Using EBG Structures ..................... 371 11.3.4 Band-Notch Operation in Patch Antennas Using EBG Structures .............................................................................. 376 11.3.6 A Low-Profile MPA Using EBG Structures .................................. 382 11.4 Real-Life Applications of EBG Patch Antennas ........................................ 391 11.4.1 High-Precision GPS....................................................................... 391 11.4.2 Wearable Electronics ..................................................................... 391 11.4.3 Radio Frequency Identification (RFID) Systems ..........................392 11.4.4 Radar Systems ............................................................................... 393 11.5 Conclusion ..................................................................................................394 References ..............................................................................................................394 11.3.5 Dual-Band and Multi-Band Characteristics Using EBG Structures ................................................................... 378 364 Printed Antennas and antenna engineering. These materials have special characteristics that do not exist in naturally occurring materials. Hence, designing metamaterials with unique char acteristics and using them in several antenna applications is an interesting concept for researchers. The concept of photonic crystals was introduced by Yablonovitch in solid-state physics [2]. The photonic crystals with a forbidden band gap are used in optics and solid-state physics. Therefore, the term photonic band gap (PBG) of the optics is used as electromagnetic band gap in the microwave domain. EBG struc tures are classified as a special type of metamaterial and can be defined as periodic or non-periodic structures that prevent or help the transmission of electromagnetic waves in a specific band of frequency [3,4]. EBG structures have many names in the literature, including left-handed materials, soft and hard surfaces, double-negative materials, negative refractive index materials, high-impedance surfaces (HIS), mag netomaterials, and artificial magnetic conductors (AMC) [5]. They are categorized into three groups: (i) three-dimensional volumetric structures, for example woodpile structure, (ii) two-dimensional planar structures, for example mushroom-like EBG structure, and (iii) one-dimensional transmission lines, such as holes in the ground plane. The EBG unit cell has a single band gap; however, a periodic arrangement of EBG structures can have multiple band gaps. In addition to the band gap feature, EBG structures also have some other important characteristics such as AMC and HIS [6]. For example, for both TE and TM polarizations, the two-dimensional EBG structures show a high-impedance surface. And when a wave strikes the EBG sur face, 0° reflection phase is obtained and the EBG surface behaves as an AMC. These special features of EBG structures lead to a broad range of applications in microwave and antenna engineering.