New EBG of CSRR with lumped capacitors applied to oscillator harmonics suppression

In this article, a compact electromagnetic band‐gap (EBG) structure is presented to reject harmonics of a crystal oscillator in the power distribution network. Compared to traditional EBG structures of complementary split ring resonator (CSRR), the proposed CSRR adding lumped capacitors (LC‐CSRR) provides a higher rejection‐performance at the series self‐resonant frequency of the lumped capacitors. A four‐layer printed circuit board is designed and fabricated to measure the S‐parameters of the proposed EBG structure, and a harmonics power testing board is presented to measure rejection performance of the proposed EBG structure. The measured results show that the proposed EBG obtains an attenuation of 60 dB over the whole range of global navigation satellite system band. By inserting the proposed EBG structure of LC‐CSRR, we measure that the harmonics powers can be decreased by 28.8 dB between the input and output of the EBG.     

Design of defective electromagnetic band‐gap structures for use in dual‐band patch antennas

Generally, the surface wave of an antenna can be suppressed by integrating the electromagnetic band‐gap (EBG) structures. However, to achieve this effect, the EBG cells must be reasonably designed, otherwise it may lead to performance degradation instead. In this article, a dual‐band pinwheel‐shaped slot EBG structure is proposed. When applied to a patch antenna, defects are introduced into 3 rows of the EBG unit cells. The proposed antenna, incorporating EBGs designed with structural defects, to radiate at 4.9 and 5.4 GHz is simulated and tested. The measured results show that the ?10‐dB bandwidth of the proposed EBG antenna is extended by 41% and 25.4% at low frequency and high frequency, respectively. In addition, the peak gain of the proposed EBG antenna is increased by 2.44 dB at 4.9 GHz and 2.86 dB at 5.4 GHz with >40% efficiency. When compared with the periodic EBG antenna, this antenna is more effective. Thus, these experimental results show that the performance of the EBG antenna can be improved by interrupting the periodicity of the EBGs structures.     

Modeling of electromagnetic band gap structures: A review

This article represents a comprehensive review of the research carried out on analytical and numerical methods modeling of electromagnetic band‐gap (EBG) structures used in around last two decades. Because of the unique characteristics of the surface wave reduction as well as perfect magnetic conductor (PMC) like behavior, the EBG structures have created their separate existence in antenna engineering society. These structures are being widely used in designing of several microwave planar circuits including printed antennas, printed microwave filters, etc. The purpose of this article is to present an inclusive review of analytical methods as well as numerical methods in the context of modeling of EBG‐structures. Such a review process is rarely carried out in the open literature to the best of authors' knowledge. The review exercise might be helpful to the researchers working on modeling of EBG‐structures as well as of EBG‐structured printed antennas, microwave planar filters, etc.     

Design,analysis, and modeling of miniaturized multi‐band patch arrays using mushroom‐type electromagnetic band gap structures

Novel designs of miniaturized multi‐band 1 × 2 patch antenna array with electromagnetic band gap (EBG) for wideband operation are presented in this article. The proposed patch array is composed of three unequal arms fed by CPW‐to‐slotline transitions to widen the impedance bandwidth with multiple resonances. By adding two conventional mushroom‐type EBG (CMT‐EBG) structures on both sides of 100 Ω slotline transitions, the compact wideband patch array (first design) is obtained. This proposed design with CMT‐EBG includes two bands with the measured ranges (S₁₁ ≤ ?10 dB) of 6.65‐6.95 GHz (C‐band) and 8.57‐11.53 GHz (X‐band). Moreover, the proposed 1 × 2 patch array with the 3 × 3 CMT‐EBG array on the one side of the structure (second design) operates at multi‐bands with the measured ?10 dB impedance bandwidths of 5.80‐5.98 GHz, 6.25‐6.47 GHz, and 8.48‐11.52 GHz. The second design compared to the first design introduces a considerable size reduction with more resonance tuning capability. The performance of the proposed designs is analyzed based on the EBG band gap properties near the slotline transitions. These designs with the EBGs indicate prominent features like resonance tuning capability, acceptable miniaturization, and enhanced impedance bandwidth with low‐fabrication cost. In this study, an equivalent circuit model of the proposed first design with EBG is also offered to describe the properties of multi‐band operation.     

Electromagnetic band‐gap structured printed antennas: A feature‐oriented survey

Wireless communication systems are playing an important role in different sectors of human society. Printed antennas are considered as the critical enabling technologies for these systems. The technology related to the design and development of printed antennas have been continuously improved from the structural view of configuration to antenna features improvement. Electromagnetic bandgap (EBG) structures have played a significant role in improving the features of printed antennas. In this paper, authors have restricted a feature–oriented comprehensive survey on EBG‐structured printed antennas. This type of survey is primarily required for the beginner working on EBG structures/EBG‐structured printed antennas. Such a survey process is rarely carried out in the open literature to the best of authors' knowledge. The proposed survey process is confined only to five different feature classifications; bandwidth improvement, gain improvement, dual‐band/multi‐band characteristics, band‐notch characteristics, and compact and low profile, respectively.     

Novel compact planar electromagnetic band‐gap structure using for ultra‐wideband simultaneous switching noise suppression

In this article, by analyzing the equivalent circuit mode for electromagnetic bandgap (EBG), a novel compact planar EBG structure is proposed for overcoming the drawback of narrow bandwidth of conventional EBG structures. The novel design is based on using meander lines to increase the effective inductance of EBG patches. The simulated and measured results demonstrate the simultaneous switching noise (SSN) can be mitigated with an ultra‐wideband from 280 MHz to 20 GHz at the restraining depth of ?40 dB. Compared with the traditional L‐bridge and meander lines EBG structures, this novel structure has the advantages of suppression bandwidth and fabrication cost. Moreover, signal integrity is achieved by the time‐domain simulation. The proposed structure provides a new kind of theoretical designing reference for EBG structure to improve the bandwidth of restraining SSN. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:429–436, 2014.     

Miniaturized rectangular waveguide filters

Two types of miniaturized rectangular waveguide filters are presented. Miniaturization is achieved using the slow‐wave effect of electromagnetic bandgap (EBG) surfaces and the left‐handed properties of split ring resonators (SRRs). The proposed EBG waveguide bandpass filter performs passband in the frequency range, which corresponds to the waveguide with the lower recommended operating band consequently enabling significant miniaturization of the structure. The SRR‐loaded bandstop filter makes use of the effect imposed by left‐handed medium (LHM), which is created by a combination of SRRs and wireline on the dielectric slab. Both filters are designed, simulated, and tested. Experimental results of the SRR‐loaded bandstop filter are presented to demonstrate feasibility of the proposed structures. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

EBG structure with T‐shaped slits for suppression of simultaneous switching noise

In this article, electromagnetic band gap (EBG) structure with T‐shaped slits is proposed for suppressing simultaneous switching noise. T‐shaped slits, bridges, and the solid ground plane are used to constitute the novel L‐EBG structure. Considering a threshold of ?35 dB, the stopband of the proposed EBG structure is about 7.29 GHz which is 1.68 GHz wider than that of a conventional L‐EBG structure. Measurement results confirm the wide bandwidth of the prototype that is predicted in simulations. In addition, the lower and upper cutoff frequencies are estimated by use of lumped‐component circuit models and parallel‐plate waveguide models, respectively. Moreover, the IR‐drop and dc resistance are examined through simulations. Additionally, common signal integrity issues in a power distribution network such as IR‐drop, DC resistance, and eye diagrams are investigated and compared to a conventional L‐EBG structure. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:419–426, 2015.     

EBG design and analysis for wideband isolation improvement between aircraft blade monopoles

A new lightweight multilayer mushroom EBG is proposed to significantly improve the isolation between collocated aircraft L‐band blade monopole antennas. Isolation improvement between two L‐bands (960‐1220 MHz) blade monopoles of nearly 20 dB is obtained with a three‐layer EBG design without requiring any redesigning or tuning of the antennas. Since the proposed EBG structure only contains very thin dielectric sheets and foam substrates it would be a lightweight structure. Moreover, the EBG being a stand‐alone structure from the antenna it can be designed, built, and placed between the antennas as an add‐on device to significantly improve antenna isolation over a relatively wide bandwidth (25%). An experimental EBG structure was built and tested demonstrating wideband isolation improvement performance.     

Study on relationships of electromagnetic band structures and left/right handed structures

Two types of dual periodic circuits are introduced. The distributions of passbands and stopbands are generated from their dispersion relationships. Based on the study, Brillouin diagrams of three representative special cases are drawn; S parameters of these three cases are simulated by Aglient ADS; the S parameters of one of the three cases are verified by an experiment. The phase characteristics are compared with those generated from the dispersion relationship. The theoretical analysis and the experimental verification show that both types of the periodic structures can behave as electromagnetic band gap (EBG) structures, right-handed structures (RHS), and left-handed structures (LHS), when they operate at different frequency ranges. Thus, the possibility of a physical structure showing these three different characteristics at different frequency ranges is proven.     

Study on relationships of electromagnetic band gap structures and left/right handed structures

Two types of dual periodic circuits are introduced. The distributions of passbands and stopbands are generated from their dispersion relationships. Based on the study, Brillouin diagrams of three representative special cases are drawn; S parameters of these three cases are simulated by Aglient ADS; the S parameters of one of the three cases are verified by an experiment. The phase characteristics are compared with those generated from the dispersion relationship. The theoretical analysis and the experimental verification show that both types of the periodic structures can behave as electromagnetic band gap (EBG) structures, right-handed structures (RHS), and left-handed structures (LHS), when they operate at different frequency ranges. Thus, the possibility of a physical structure showing these three different characteristics at different frequency ranges is proven.     

紧凑型电磁带隙结构的设计方法分析

为了在有限空间放置能够起作用的电磁带隙结构数量,必须减小电磁带隙结构的尺寸。针对此问题,总结了电磁带隙结构两种类型的带隙形成的物理机理,根据带隙形成机理给出了设计小型化紧凑电磁带隙结构的思路,并依据此思路设计了一种紧凑型电磁带隙结构。仿真结果表明,新电磁带隙结构在中心频率3.28GHz处得到了900MHz的禁带宽度,相对带宽达到27.4%。     

Analysis for scattering of conductive objects covered with anisotropic magnetized plasma by trapezoidal recursive convolution finite‐difference time‐domain method

The finite‐difference time‐domain method (FDTD) is extended to three‐dimensional (3D) anisotropic magnetized plasma based on the trapezoidal recursive convolution (TRC) technology. The TRC technique requires single convolution integral in the formulation as in the recursive convolution (RC) method, while maintaining the accuracy comparable to the piecewise linear recursive convolution (PLRC) method with two convolution integrals. In this article, the numerical results indicate that the TRC‐FDTD method not only improves accuracy over the RC‐FDTD with the same computational efficiency but also spends less computational time than the PLRC‐FDTD based on the same accuracy. The 3D TRC‐FDTD formula is provided and the bistatic radar scattering sections of conductive targets covered with anisotropic magnetized plasma are calculated. The results show that magnetized plasma cover layer can greatly reduce echo energy of radar targets, and the anisotropic magnetized plasma cover has better absorption effect than nonmagnetized. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Computer simulation of polarization rotation characteristics of graphene

The magnetically biased graphene has the polarization rotation characteristics which is useful to design the polarizer. But this characteristic is difficult to simulate by using the finite‐difference time‐domain (FDTD) method, not only due to the graphene's thin layer which confines the time step size, but also because of graphene's isotropic surface conductivity when it is biased by static magnetic field. To solve this problem, this study presents an anisotropic hybrid implicit‐explicit FDTD method. This method uses auxiliary difference equations to represent graphene's conductivity, and removes the confinement of graphene's thickness on time step size by using hybrid implicit‐explicit technique. So, compared with FDTD method, the presented method can save a large number of computational time, which are validated by numerical examples.     

Multilayer EBG structure for ultra‐wide band SSN mitigation using embedded spiral‐shaped planes

A novel multilayer electromagnetic bandgap (EBG) structure with two spiral‐shaped planes embedded between the power plane and the traditional high‐impedance surface (HIS) is presented. The equivalent capacitance between the power plane and the HIS and the self‐inductance of the patch can be increased significantly, while the self‐inductance of the power plane is decreased. The proposed EBG structure performs excellent ultra‐wide band simultaneous switching noise mitigation and keeps signal integrity in high‐speed digital circuits. The suppression bandgap of the design is from 0.6 to 15 GHz at ?30 dB. Good performance is validated by both simulation and measurement. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Pattern reconfigurable metasurface to improve characteristics of low profile antenna parameters

This article proposes a mushroom‐shaped electromagnetic band gap (EBG) structure for the antenna parameter enhancement of low profile antennas in 5 to 15 GHz regime. Three different type antennas including a dipole antenna, a loop antenna, and a monopole antenna are designed for the corresponding operation band, and a 8 × 8 mushroom type EBG structure is designed to obtain exotic behavior for the enhancement of antenna parameters. Bandwidth, return loss (S₁₁), main lobe gain, directivity, side lobe level, front to back ratio, and angular width of each antenna with EBG structure is examined with details. Besides, the designed EBG structure and antennas are fabricated and experimental results are obtained to support numerical ones. In addition, future study of the proposed EBG structure such as microwave imaging in cavity resonators is specified and discussed.     

Use of partially overlapped suspended substrate striplines for the realization of wideband microwave filters

This article presents realization of low loss, wide stop‐band suspended substrate stripline (SSS) wideband pass filters using interdigital and stepped‐impedance resonators. SSSs have been characterized using the finite‐difference method (FDM). The experimental results of the fabricated filters are compared with the theoretical results. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Modeling and optimization of cylindrical antennas using the mode‐expansion method and genetic algorithms

For monopole antennas with cylindrically symmetric structures, a mode‐expansion method is highly time efficient, which is a realistic approach for integrating function‐optimization tools, such as genetic algorithms (GAs), in order to extract the best bandwidth property. In this article, a mode‐expansion method is used to simulate the impedance characteristics of the cylindrical antennas. As examples, two new types of monopole antennas are presented, one of which possesses a two‐step top‐hat structure while the other has an annulus around the stem. After the modeling scheme is examined for convergence and data validity, the associated optimization problem, with dimensions as decision variables, structural limitations as linear constraints, and desired bandwidth performance as an objective function, is solved using GAs. The effects of the geometric parameters on the impedance characteristics are investigated in order to demonstrate the optimality of the calculated solutions. Two optimized practical antennas are designed based on our numerical studies. One has a broad bandwidth of 3 GHz while the other shows a dual‐band property, which can satisfy the bandwidth requirements for both Bluetooth (2.45‐GHz band) and WLAN (5‐GHz band) systems. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

New multi‐standard dual‐wideband and quad‐wideband asymmetric step impedance resonator filters with wide stop band restriction

New multi‐standard wide band filters with compact sizes are designed for wireless communication devices. The proposed structures realize dual‐wideband and quad‐wideband characteristics by using a new skew‐symmetrical coupled pair of asymmetric stepped impedance resonators, combined with other structures. The first and second dual‐wideband filters realize fractional bandwidths (FBW) of 43.2%/31.9% at the central frequencies (CF) of 1.875/1.63 GHz, and second bandwidths of 580 MHz/1.75 GHz at CF of 5.52/4.46 GHz, respectively. The proposed quad‐band filter realizes its first/second/third/fourth pass bands at CF 2.13/5.25/7.685/9.31 GHz with FBW of 46.0%/11.4%/4.6% and 5.4%, respectively. The wide pass bands are attributed to the mutual coupling of the modified ASIR resonators and their bandwidths are controllable by tuning relative parameters while the wide stop band performance is optimized by the novel interdigital cross coupled line structure and parallel uncoupled microstrip line structure. Moreover, the quad band is generated by introducing the novel defected rectangle structure. These multi‐standard filters are simulated, fabricated and measured, and measured results agree well with both simulated results and theory predictions. The good in‐band and out‐of‐band performances, the miniaturized sizes and simple structures of the proposed filters make them very promising for applications in future multi‐standard wireless communication.