Mushroom-type Electromagnetic Bandgap Structure Research Articles

A 77 GHz Transmit Array for In-Package Automotive Radar Applications

A packaged transmit array (TA) antenna is designed for automotive radar applications operating at 77 GHz. The compact dimensions of the proposed configuration make it compatible with standard quad flat no-lead package (QFN) technology. The TA placed inside the package cover is used to focus the field radiated by a feed placed in the same package. The unit cell of the array is composed of two pairs of stacked patches separated by a central ground plane. A planar patch antenna surrounded by a mushroom-type EBG (Electromagnetic Band Gap) structure is used as the primary feed. An analytical approach is employed to evaluate the primary parameters of the suggested TA, including its directivity, gain and spillover efficiency. The final design has been refined using comprehensive full-wave simulations. The simulated gain is 14.2 dBi at 77 GHz, with a half-power beamwidth of 22°. This proposed setup is a strong contender for highly integrated mid-gain applications in the automotive sector.

UWB dual-notched planar antenna by utilizing compact open meander slitted EBG structure

In this paper, an ultra-wideband (UWB) dual-notch planar antenna is presented. The antenna, in its structure, utilizes a compact electromagnetic bandgap (EBG) structure with new open meander slits to notch two frequency bands at around 3.5 and 5.5 GHz. The main idea is to place the new slitted mushroom-type EBG structure at the vicinity of the feedline to achieve filtering ability for the antenna. The presented EBG structure has many benefits, like notched bands with sharp roll off, independent control over the notched bands, little effects on antenna performance, easy switching configuration and reduction of the required number of EBG cells. The fabricated antenna shows −10 dB bandwidth of 2.63 up to 13 GHz with dual-notched in the frequency bands of 3.11–4.01 GHz and 5.15–5.98 GHz. Simulation and experimental results exhibit a close agreement with each other. The proposed UWB antenna with a flat transfer function and a constant group delay at the notched bands is a suitable choice for compact UWB communication systems.

A planar CPW fed UWB antenna with dual rectangular notch band characteristics incorporating U‐slot, SRRs , and EBGs

In this article, a planar ultra-wideband (UWB) antenna with dual rectangular notchband characteristics (ie, 5.94-7.50 GHz and 8.02-10.46 GHz) is presented. The two-notch bands are chosen based on various wireless applications operating in C-band and X-band. The size of the antenna is very compact (25 × 25 × 1.6 mm3) and is designed on a low-cost FR4 substrate. Co-planar waveguide (CPW) feed and beveling techniques are utilized for achieving the UWB operation. In order to yield the first rectangular notch, a U-slot and a pair of split-ring resonators are embedded into the radiating patch and the backside of the design, respectively. The coupling between these two structures is adjusted so as to achieve a rectangular band-notch operation. The second rectangular notch has been achieved by introducing the two mushroom type electromagnetic band-gap structures on the opposite side of the CPW feed. The parametric analysis for controlling band notches, time-domain analysis, and filter synthesis is also presented. Finally, simulated as well as measured results of S11, gain, radiation pattern, group delay, and total efficiency are demonstrated to show the suitability of this design for UWB systems.

On the Increment of the Bandwidth of Mushroom-Type EBG Structures With Glide Symmetry

Mushroom-type electromagnetic bandgap (EBG) structures are known to operate as high-impedance surfaces at low-frequency bands. They are broadly used in the microwave regime. However, one of the main drawbacks of mushroom-type EBG structures is their narrow bandwidth. In this article, we propose a mushroom-type EBG structure with glide-symmetric edge vias to increase the operational bandwidth. This bandwidth increment is explained by the physical insight provided by an equivalent circuit model of the structure as well as the description of the field behavior. Simulation and measurement results show an improvement of approximately 67% over the case without glide symmetry in the structure. We conclude that applying glide symmetry to the mushroom-type EBG structures can improve their bandwidth without adding additional manufacturing costs.

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.

2-D Equivalent Source Method for a Finite Periodically Loaded Multiconductor Transmission Line Analysis With an Application to EBG Power Distribution Networks

A novel theoretical model based on an equivalent source method and a modal superposition technique is proposed to derive a dyadic Green's function for two-dimensional (2-D) finite periodically loaded multiconductor transmission lines (MTLs) to efficiently analyze electromagnetic band gap (EBG) structures embedded in power distribution networks (PDNs) for noise suppression. Many of such structures can be easily modeled using an MTL model with periodically loaded series and shunt components. By treating each periodic load as an equivalent local current source at the center of each unit cell, based on equivalent source theory, a finite uniform 2-D MTL excited by a group of equally spaced equivalent current sources is obtained. The amplitude of these local exciting sources may be analytically evaluated for the modes in the structure. Upon identifying these local equivalent current sources, a simple analytical expression for the 2-D dyadic Green's function is derived based on the modal superposition technique. For validation, a mushroom-type EBG structure embedded in a typical PDN is examined using the proposed approach and comparison with full-wave simulations and measurements are presented.

Optimization of Electromangnetic Band Gap Structure for Mutual Coupling Reduction in Antenna Arrays-A Comparative Study

In this paper, two new three layer (stacked) Electromagnetic Band Gap structures are proposed, named as Stacked Electromagnetic Band Gap (SEBG) and Progressive Stack Electromagnetic Band Gap (PSEBG) structures. Its electromagnetic (EM) properties are determined by using Finite element method (FEM) based simulator and obtained results are compared with classical mushroom type electromagnetic band gap (MEBG) structure. Both SEBG and PSEBG structures proposed in this paper consists of two layers above the conducting ground plane; a lower layer, contains array of small MEBGs with square patches and an upper layer contains square planar MEBG structure. Vertical conducting stubs passing through substrate shorting all square patches in both the layers with conducting ground. Three EBG structures are exhibiting the property of forbidden band gap (FBG), where surface wave propagation is restricted. The FBG property helps in minimization of mutual coupling between array antennas when electromagnetic band gap structures are incorporated between array elements. In this paper, the level of coefficient of mutual coupling between array antenna in the presence of SEBG and PSEBG are investigated, obtained results are compared with classical MEBG results. The co-efficient of mutual coupling is reduced up to 12dB in the presence of proposed models.

A Miniaturized Electromagnetic Bandgap Structure Using an Inductance-Enhanced Patch for Suppression of Parallel Plate Modes in Packages and PCBs

In the packages and printed circuit boards (PCBs) of high-speed and mixed-signal electronics, parallel plate waveguides (PPWs) are frequently used as the power/ground plane pair, resulting in a significant problem of electrical switching noise such as simultaneous switching noise and ground bounce noise. This noise inevitably deteriorates system performance. In this paper, we propose an electromagnetic bandgap (EBG) structure using an inductance-enhanced patch (IEP) to suppress PPW modes in high-speed and compact packages and PCBs. The noise suppression characteristics of the proposed IEP-EBG structure were thoroughly analyzed using a dispersion diagram based on a full-wave simulation as well as an equivalent circuit model of a unit cell structure with a Floquet boundary condition. The proposed IEP-EBG structure has the advantages of substantial reductions in the low cut-off frequency of the first stopband as well as unit cell size when compared to a conventional mushroom-type EBG structure without the inductance-enhanced technique. The suppression of the PPW modes of the proposed IEP-EBG structure was verified using measurements of scattering parameters. In the measurements, the low and high cut-off frequencies of the first stopband of the IEP-EBG structure were found to be 1.55 GHz and 2.48 GHz, respectively, while those of the conventional mushroom type EBG structure were 3.52 GHz and 5.3 GHz. For the low cut-off frequency, a 56% reduction was achieved, resulting in substantial miniaturization suitable for compact packages and PCBs.

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.

A Comparison of Three Uniquely Different State of the Art and Two Classical Multiobjective Optimization Algorithms as Applied to Electromagnetics

This paper compares three modern and two classical multiobjective optimizers (MOOs) as applied to real-world problems in electromagnetics. The behavior of sophisticated optimizers on simple test functions has been studied exhaustively. In contrast, the algorithms here are tested on practical applications, where the function evaluations are computationally expensive, making the convergence rate a crucial factor. The examples considered include the optimization of a narrowband slot antenna, a mushroom-type electromagnetic bandgap structure, and an ultrawideband Vivaldi antenna. Another popular topic in the literature is in comparing classical MOOs on electromagnetics problems. The modern optimizers chosen in this paper are state of the art and each has a distinct design philosophy. This paper introduces two unique MOOs to the electromagnetics community: BORG, an auto-adaptive genetic algorithm and the Multi-Objective Covariance Matrix Adaptation Evolutionary Strategy (MO-CMA-ES), an extension of the popular single-objective CMA-ES. These algorithms are compared to the Multi-objective Evolutionary Algorithm based on Decomposition (MOEA/D), a Chebysheff scalarization algorithm, and two classical MOOs. This paper will study the behavior of these algorithms on problems in electromagnetics with a limited number of function evaluations using five distinct metrics and will provide useful guidelines and recommended optimizer settings.

DESIGN AND ANALYSIS OF META-MATERIAL BASED WLAN ANTENNA

In this paper, a 2.42 GHz micro-strip patch antenna is designed and analyzed using a conventional and a metamaterial (artificial) based Electromagnetic Bandgap (EBG) ground planes. The directivity, return loss and VSWR of the conventional 2.42 GHz patch antenna were found to be 5.23dB, -13.2dB, and 1.5 respectively. The proposed antenna then being mounted on a Mushroom-type EBG structures (artificial ground plane) produced better far-field performance as compared to conventional counterpart i.e. the return loss, directivity and VSWR were improved by 80.3%, 58.5% and 24.6%. The WLAN antenna was designed and tested on a miniaturized slotted EBG structure. The slotted EBG was 11.4 % compact as compared to the mushroom structure. The directivity, return loss and VSWR of the antenna using the slotted EBG are improved by be 51%, 31.8%, 15.4% respectively as compared to the patch conventional WLAN patch antenna. The antenna can be used for WLAN applications.

A Compact EBG Structure With Wideband Power/Ground Noise Suppression Using Meander-Perforated Plane

In this letter, we propose a miniaturized and wideband electromagnetic bandgap (EBG) structure with a meander-perforated plane (MPP) for power/ground noise suppression in multilayer printed circuit boards. The proposed MPP enhances the characteristic impedance of the EBG unit cell and improves the slow-wave effect, thus achieving the significant size reduction and the stopband enhancement. To explain the prominent results, a dispersion analysis for the proposed MPP-EBG structure is developed. Compared to a mushroom-type EBG structure, it is experimentally demonstrated that the MPP-EBG structure presents a 57% reduction in the start frequency of the bandgap, which leads to a 74% reduction in a unit cell size. In addition, the MPP-EBG structure considerably improves the noise suppression bandwidth (−40 dB) from 0.8 to 4.9 GHz compared to the mushroom-type EBG structure.

The Synthesis of Wide- and Multi-Bandgap Electromagnetic Surfaces With Finite Size and Nonuniform Capacitive Loading

A method is presented that allows for the efficient design of capacitively loaded finite-size electromagnetic bandgap (EBG) structures, which can target a wide range of design objectives. The design flexibility is achieved by adding arbitrary nonuniform capacitive loading to an underlying periodic EBG structure. This system can be interpreted as having an effective aperiodic structure, which allows more design flexibility in terms of bandgap engineering. To choose the proper capacitances, a powerful global optimization technique known as the covariance matrix adaptation evolutionary strategy is employed that is aided by a fast port-reduction strategy. This approach avoids the need to carry out multiple computationally expensive full-wave simulations during the course of the optimization process by requiring only a single full-wave simulation be performed prior to initiating the optimization. To demonstrate the utility of this method, the capacitive loading of a mushroom-type EBG structure in a parallel-plate waveguide is optimized to reduce transmission from 2.4 to 7 GHz. This design was fabricated and the measured response was found to be in good agreement with the simulations. Using the same initial full-wave simulation, another structure was designed to improve isolation at the 2.4-, 3.6-, and 5-GHz WLAN bands to below -22 dB. An additional set of structures are also designed using capacitively loaded mushroom-type EBG surfaces without placing them inside of a parallel-plate waveguide.

Fractal monopole antenna with electromagnetic bandgap structure for UWB applications

This article presents the design and performance measures of a fractal monopole antenna with band rejection characteristics for ultrawide band applications. Fractal concept is incorporated to miniaturize the antenna dimension and to enhance its radiation and broadband properties. Mushroom type electromagnetic bandgap structures are introduced near the micristrip feed line to reject the WLAN frequency band. The proposed antenna operates in the frequency range 3.2–12.4 GHz with average gain of 5 dB and maximum efficiency of 97.6%. The rejection band ranges from 5.09 to 5.97 GHz. Consistent radiation characteristics exist within the operating band. The performance of the proposed antenna is confirmed by simulation and experimental results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1872–1874, 2014

A Compact and Wideband Electromagnetic Bandgap Structure Using a Defected Ground Structure for Power/Ground Noise Suppression in Multilayer Packages and PCBs

In this paper, we propose a compact and wideband electromagnetic bandgap (EBG) structure using a defected ground structure (DGS) to significantly enhance the wideband suppression of power/ground noise coupling in multilayer packages and printed circuit boards. The proposed EBG structure is implemented simply by adding a rectangular-shaped DGS which is etched periodically onto the ground plane without changing any other geometrical parameter from a mushroom-type EBG structure. The DGS effects on the f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</sub> are thoroughly analyzed using the dispersion characteristics. We experimentally verified that the proposed EBG structure achieved the wideband power/ground noise suppression (below -40 dB) between 2.5 and 16.2 GHz. In addition, we demonstrated the considerable reduction in f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> from 3.4 to 2.5 GHz and a significant increase in f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</sub> from 9.1 to 16.2 GHz when compared with the mushroom-type EBG structure.

The forbidden bandgap characteristic of EBG structures

AbstractThe bandgap characteristics of several electromagnetic bandgap (EBG) structures are compared, and parametric studies of a wideband uniplanar compact photonic bandgap (UC‐PBG) structure are carried out. It has been presented that the bandgap bandwidth of the mushroom type EBG structure increases when a lower dielectric constant substrate is used or when a larger substrate thickness is used. However, for the UC‐PBG structures, which do not have shorting vias, the bandgap characteristic does not follow the trend as it is in the EBG structure with shorting via. Moreover, it is demonstrated that the bandgap frequency varies with the dielectric constant of the substrate, but the bandgap bandwidth does not have particular trend with the dielectric constant of the substrate. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2965–2967, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23804

Radiation Characteristics of a Microstrip Patch Over an Electromagnetic Bandgap Surface

Radiation characteristics of a microstrip patch over an electromagnetic bandgap (EBG) substrate are investigated in this paper. This paper focuses on a mushroom-type EBG structure, although the design is applicable to various EBG profiles. The patch antenna is modeled as a half-wavelength resonator of an EBG-loaded microstrip transmission line. Through a full-wave eigenmode analysis of a microstrip line on an EBG structure, it is found that the resonant patch will not see a high-impedance surface (HIS), but rather it is coupled to the EBG structure as an open cavity resonator. Due to strong near-field coupling, the propagation characteristics including the bandgap zones are very different with or without the patch cover. The use of an EBG structure as a bulk material for antennas is seen inappropriate. The EBG surface is found to have the effect of reducing the patch resonant length and bandwidth. A prototype of a microstrip line proximity fed to a patch antenna is fabricated and tested to verify the analysis.