Electromagnetic Bandgap Array Research Articles

An EBG-Based Triple-Band Wearable Antenna for WBAN Applications.

In this article, a triple-band wearable monopole antenna fed by a coplanar waveguide (CPW) with an integrated electromagnetic bandgap (EBG) array is proposed. The monopole antenna consists of an asymmetric inverted U-shaped strip, a horizontal branch, and an L-shaped ground stub, which can generate the 2.45/5.8 GHz wireless local area network (WLAN) band and the 3.5 GHz worldwide interoperability for microwave access (WiMAX) band. To reduce the influence of antenna radiation on the human body, a triple-band 3 × 3 EBG array has been integrated into the back of the monopole antenna. The EBG unit is composed of two rectangular rings and a circular ring, and the operating frequencies correspond to the triple bands of the monopole antenna. In this paper, the impedance and radiation performances of the stand-alone monopole antenna and the integrated antenna are analyzed, and the safety for the human body is evaluated based on specific absorption rate (SAR) values. The proposed triple-band antenna can be used in wearable devices in wireless body area networks (WBANs).

Wearable Antenna Sensor Based on EBG Structure for Cervical Curvature Monitoring

With the popularization of electronic products, more and more people have cervical spine troubles. This paper proposed an antenna sensor for detecting the bending state of the neck in people&#x2019;s daily life. The antenna works in the 2.45 GHz industrial, scientific, and medical (ISM) band. When the cervical spine drives the antenna sensor to bend, the resonance frequency of the antenna sensor shifts. Based on this characteristic, the antenna sensor can monitor the bending angle of the cervical spine wirelessly. Placing a <inline-formula> <tex-math notation="LaTeX">${2}\times {2}$ </tex-math></inline-formula> electromagnetic bandgap (EBG) array between the antenna sensor and the neck reduces the specific absorption rate (SAR) of the human body by about 90&#x0025; and increases the peak gain from 2.46 dBi to 6.75 dBi. Even if the antenna sensor is bent and deformed greatly, the gain of the antenna sensor remains good. The efficiency of the antenna sensor loaded with the EBG array keep at 65&#x0025;, and the sensitivity to the bending angle reaches 7.5 MHz/1&#x00B0;. The measured results of the fabricated antenna sensor are in good agreement with the simulated ones. The experimental results show that the proposed antenna sensor is suitable for cervical curvature monitoring.

Gain Enhancement of Dielectric Resonator Antenna Using Electromagnetic Bandgap Structure

High gain antennas are highly desirable for long-range wireless communication systems. In this paper, a compact, low profile, and high gain dielectric resonator antenna is proposed, fabricated, experimentally tested, and verified. The proposed antenna system has a cylindrical dielectric resonator antenna with a height of 9 mm and a radius of 6.35 mm as a radiating element. The proposed dielectric resonator antenna is sourced with a slot while the slot is excited with a rectangular microstrip transmission line. The microstrip transmission line is designed for a 50 Ω impedance to provide maximum power to the slot. As a result, the proposed antenna operates at 5.15 GHz with a 10-dB absolute bandwidth of 430 MHz (4.98 – 5.41 GHz). It is important to mention that the gain of the dielectric resonator antenna is enhanced by the introduction of an electromagnetic bandgap (EBG) structure. In fact, EBG units are placed below the antenna, which enhances the realized peak gain from 5.32 dBi to 8.36 dBi at 5.15 GHz. More specifically, a gain enhancement of 3.04 dB is observed with the introduction of the EBG array. This antenna has several good features such as high gain, compact size, large bandwidth, and lower losses which make it a suitable choice for long-range wireless communication systems.

SAR reduction and gain enhancement of compact wideband stub loaded monopole antenna backed with electromagnetic band gap array

This article discusses a design of compact wideband stub loaded monopole antenna (CWSLMA) backed with 3 × 3 array of hexagonal shaped electromagnetic band gap (EBG) cell operating at 2.45 GHz with enhanced gain and low specific absorption rate (SAR) for wireless body area network (WBAN) applications. The split ring rectangular shaped radiator is designed with protruding stub to miniaturize the antenna size of monopole antenna (34 × 18 × 1.6 mm3) at resonance frequency 2.45 GHz. The proposed CWSLMA is fabricated on glass epoxy FR4 substrate supported with 3 × 3 array of hexagonal shaped EBG cell over Kapton polyimide flexible substrate. The proposed antenna consists of simulated 10 dB return loss (RL) bandwidth (BW) of 16.7% (2.3–2.72 GHz). The proposed 3 × 3 array of hexagonal shaped EBG cell enhances the realized gain of proposed CWSLMA to 7 dBi by reducing the back-lobe radiation. The EBG array also increased the isolation between fabricated wearable antenna and human body and thus, reduced SAR to 0.44 W/kg (tested over 10 g of human tissues) at frequency 2.45 GHz. The fabricated proposed CWSLMA with EBG achieved a measured 10 dB RL bandwidth of 17.3% (2.27–2.7 GHz) and a measured group delay below than 1 ns in entire operational band with measured gain of 6.8 dBi. The proposed CWSLMA with EBG is designed, fabricated, and tested. The measured results of fabricated antenna prototype are verified and validated with simulated ones.

Wearable antenna pressure sensor with electromagnetic bandgap for elderly fall monitoring

In this paper, a wearable antenna pressure sensor with electromagnetic bandgap (EBG) is proposed, which can be used to monitor the walking and fall states of the elderly. When the elderly walks and falls suddenly, the knee or elbow wearing the antenna sensor will touch the ground and put a lot of pressure on the antenna sensor, resulting in the resonance frequency shifts. The proposed antenna sensor is fabricated on flexible silicone substrate and works in the 2.45 GHz industrial, scientific and medical (ISM) band. A 3 × 3 EBG array is designed to reduce the specific absorption rate (SAR) of the antenna to the human body and increase the forward peak gain of the antenna from 1.63dBi to 4.36dBi. Furthermore, the antenna sensor exhibits high sensitivity of about 11 MHz/N to the pressure. To verify the simulated results, the sensing properties of the wearable antenna sensor were measured. The measured results have been found to be consistent with the simulated ones. Moreover, the bending performance study and SAR analysis reveal that the proposed antenna sensor is a good candidate for wearable devices.

A Novel Waveguide-Below-Cutoff Structure With an Extended Cutoff Frequency

In this letter, a novel waveguide-below-cutoff (WBC) structure with electromagnetic bandgap (EBG) surfaces is proposed to increase the cutoff frequency without sacrificing the waveguide size. To implement the proposed WBC structure, EBG arrays with various via patterns are fabricated and attached to the wide walls inside a normal rectangular waveguide. Transmission loss of the WBC structure is measured in terms of different EBG arrays, and it is confirmed that the cutoff frequency could be extended to higher frequencies accordingly.

Wearable high gain low SAR antenna loaded with backed all‐textile EBG for WBAN applications

A high gain, low specific absorption rate, oval-shaped monopole antenna is presented. It is backed by an all-textile 3 × 3 array of electromagnetic bandgap (EBG) unit cells. The antenna is printed on the thin Rogers ULTRALAM 3850 substrate, while the EBG array is composed of the conductive ShieledIT Super and dielectric substrate felt. The design operates at 2.45 GHz of the Industrial, Scientific, and Medical band. Due to the close distance between the extended grounds of the co-planar waveguide feeding configuration and the oval-shaped monopole antenna, current-coupling was achieved, leading to gain enhancement. However, with body-loading cases, resonance at 2.45 GHz was attained at a separation of 30 mm. By incorporating the EBG array, as an isolator, this issue was resolved. In free space and over a gap of 3 mm from the human body, gain enhancements by 2.68 and 11.54 dB were achieved at 2.45 GHz, respectively. Simulated and measured results are benchmarked. Furthermore, SAR simulation study showed reductions by 99.5%, averaged over 1 and 10 g of tissue.

Multi-Mode High-Gain Antenna Array Loaded With High Impedance Surface

A novel and simple broadband antenna array loaded with high impedance surface is proposed in this letter. The unit cell is composed of a main radiating patch and a pair of EBG arrays placed symmetrically at the two radiating edges of the main radiating patch. The main radiating patch is responsible for the original TM10 mode while the electromagnetic bandgap (EBG) arrays is for another resonant mode characterized as quasi-TM20 mode. Thus, wideband performance is obtained due to the combination of the two generated resonant modes. And on this basis, by adding symmetrical mushroom structures at the other two edges of the main radiating patch, the impedance bandwidth and sidelobe suppression are improved. The current distributions on the all metal patches are almost uniform, therefore high gains can be obtained during the whole operating bandwidth. The antenna array is formed by 4 × 4 unit cells and the prototype is fabricated to validate the design. The measured results show that the impedance bandwidth is broadened from 11.1 to 15.6 GHz with the peak-gain reaching as high as 18.8dBi. Besides, the proposed antenna is easy fabrication with low profile which provides great convenience in the actual beam and point-to-point communication applications.

Compact Monopole Antenna Backed With Fork-Slotted EBG for Wearable Applications

A compact, low-profile ultrawideband directional antenna for a wireless body area network (WBAN) is reported in this letter. The directional antenna is designed using a monopole backed with an electromagnetic bandgap (EBG) structure, which acts as a reflector. The beveled Y-shaped monopole antenna covers the ultrawide bandwidth from 3.1 to 10.6 GHz. The monopole antenna backed with a fork-slotted EBG is designed with a size of 8 × 8 mm2. The 2 × 1 EBG array is printed on the same plane above the partial ground. This integrated structure provides band-stop characteristics from 3.1 to 10.6 GHz with a directional radiation pattern intended for wearable applications. It also acts as a protective shield against the electromagnetic radiation emerging from the monopole antenna toward the body tissue. The proposed directional antenna provides a peak gain of 6.25 dBi with high radiation and total efficiency. The calculated specific absorption rate value is 0.695 W/Kg, which is well below the desired 1.6 W/kg.

An Electromagnetic Bandgap Structure Integrated With RF LNA Using Integrated Fan-Out Wafer-Level Package for Gigahertz Noise Suppression

This paper presents a periodic electromagnetic bandgap (EBG) structure in the integrated fan-out wafer-level package (InFO-WLP) technology for gigahertz-band noise suppression. The proposed EBG structure consists of an $LC$ resonator with two symmetrical spiral inductors in series and a shunt metal–insulator–metal capacitor between power and ground planes. The third-order equivalent model of the EBG structure is also proposed and extracted by field solver ANSYS Q3D to model the performance. In addition, the EBG arrays with different sizes of unit cell and the corresponding stopband bandwidth and isolation were characterized. The measurement results show that the proposed $1 \times 4$ EBG array of 600- $\mu \text{m}$ square unit cell can achieve a 29.5-GHz stopband bandwidth together with an over 30-dB isolation level. Furthermore, by using the InFO-WLP technology, the proposed EBG structure is integrated with an RF low-noise amplifier (LNA) fabricated in a 16-nm FinFET technology as a case study to validate the power noise immunity. The experimental results show that the measured output spectrum of LNA integrated with the proposed EBG structure at the power plane can suppress the noise tone from −37.37 to −68.65 dBm.

Unit-Cell-Based Domain Decomposition Method for Efficient Simulation of a Truncated Electromagnetic Bandgap Structure in High-Speed PCBs

In this paper, we present a unit-cell-based domain decomposition method (UC-DDM) for rapid and accurate simulation of predicting the parallel plate noise (PPN) suppression of a truncated electromagnetic bandgap (EBG) structure in high-speed printed circuit boards (PCBs). The proposed UC-DDM divides the analysis domain of the truncated EBG structure into UCs as sub-domains. Solving a sub-domain is based on a novel UC model, yielding an analytical expression for the impedance parameter (Z-parameter) of the UC. The novel UC model is derived using a spatial decomposition technique, which results in the modal decomposition of quasi-transverse electromagnetic (TEM) and transverse magnetic (TM) modes. In addition, we analytically derive a impedance-parameter recombination method (ZRM) to obtain the analytical solution of a finite EBG array from the sub-domain results. The proposed UC-DDM is verified through comparison with full-wave simulation results for various EBG arrays. Comparison between the UC-DDM and a full-wave simulation of a truncated EBG structure reveals that a substantial improvement in computation time with high accuracy is achieved. It is demonstrated that the simulation time of the proposed method is only 0.1% of that of a full-wave simulation without accuracy degradation.

An On-Chip Electromagnetic Bandgap Structure with ESD Protection for Noise Suppression in 16-nm FinFET CMOS

By using periodical electromagnetic bandgap (EBG) structure, a wideband band-stop filter (BSF) with ESD protection is first realized in 16-nm FinFET CMOS technology for GHz-order noise suppression. The proposed EBG unit cell consists of an on-chip inductor in series with MOS capacitors and gated ESD diodes. The gated ESD diodes are not only used as ESD protection devices, but also co-designed with MOS capacitors and an inductor to form LC resonator for the BSF. The measurement results demonstrate TLP currents of 1.75 A and 1.35 A for the PDS and NDS modes, respectively, corresponding to a HBM ESD level over 2 kV. With the consideration of metal density rule for power/ground mesh, the on-chip EBG array presents a stopband of 15.5 GHz, from 4.5 to 20 GHz, with an isolation level of 30 dB.

EBG 구조를 이용한 메탈 프레임 스마트폰 내의 전자파 간섭 저감

최근 프리미엄급 스마트폰들은 대부분 메탈 프레임을 채용하고 있으며, 이는 중저가 스마트폰으로 확산되고 있는 추세이다. 하지만, 메탈 프레임은 스마트폰 내 디지털 부품에서 발생하는 전자파 노이즈의 좋은 전달 경로가 되어, 스마트폰 상단부 또는 하단부에 위치한 무선 안테나에 전자파 간섭을 일으키는 원인이 될 수 있다. 본 논문에서는 메탈 프레임에 EBG(Electromagnetic Band Gap) 구조를 적용하여 안테나로의 전자파 간섭을 줄일 수 있는 방법을 제안하였다. <TEX>$7{\times}6$</TEX> 배열의 다중 비아(Multi-via) EBG 구조를 갖는 메탈 프레임을 설계하였으며, 이를 적용할 경우, 메탈 프레임을 통한 표면 전자파 노이즈 간섭을 20 dB 정도 저감시킬 수 있음을 시뮬레이션을 통해 확인하였다. Recent premium smartphones commonly employ a metal frame and this trend is currently spreading over mid-range smartphones. However, the metal frame becomes a good coupling path of electromagnetic noises emitted from digital components in smartphones and then increases radio-frequency interference(RFI) to RF antennas located at top and bottom sides of smartphones. This paper proposed a metal frame with EBG(Electromagnetic Band Gap) structure to reduce the noise coupling to antenna by suppressing surface wave on the metal frame. By simulation, it is confirmed that the proposed metal frame with <TEX>$7{\times}6$</TEX> mushroom-type EBG array pattern with multi-via can reduce the noise coupling to RF antenna by about 20 dB.

Multi-stack Technique for a Compact and Wideband EBG Structure in High-Speed Multilayer Printed Circuit Boards

We propose a novel multi-stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high-speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS-EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS-EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port-to-port spacing than the unit-cell length, thus overcoming a limitation of previous EBG structures.

A Low Mutual Coupling Design for Array Microstrip Antennas Integrated with Electromagnetic Band-Gap Structures

Developing and employing methods to reduce the mutual coupling between elements of an antenna array has become a hot topic in the design of antenna arrays. The utilization of electromagnetic band-gap (EBG) structures is an attractive way to reduce surface wave excitation in printed antenna geometries so to mitigate the mutual coupling problem. This paper investigates the performance of a microstrip antenna phased array embedded in an EBG. A novel EBG array configuration is proposed, the band-gap feature of mushroom-like EBG has been studied, its band-gap feature of surface-wave suppression is demonstrated by plotting variations of the transmission coefficient S12 with frequency and dispersion diagram. The antenna design is verified by High Frequency Structural Simulator (HFSS), the simulating results show that the EBG design approach is a good candidate for a reduction in mutual coupling at certain frequencies between radiator elements, which in turn increases antenna directivity.

Mutual coupling reduction in waveguide-slot-array antennas using electromagnetic bandgap (EBG) structures

The application of an electromagnetic bandgap (EBG) structure as a tool for reduction of mutual coupling in planar waveguide-slot-array antennas (WSAA) is investigated for the first time. First, surface-wave suppression was demonstrated by placing an EBG array over the ground plane of a linear 1 × 4 waveguide-slot-array antenna. Two 1 × 4 waveguide-slot-array antennas were then put next to each other, with the EBG array over the conducting plane separating them, and up to 10 dB reduction in mutual coupling was observed. Based on these achievements, a planar 2 × 4 waveguide-slot-array antenna was designed using the EBG array to reduce mutual coupling. The EBG array compensated for the undesired frequency shift due to mutual coupling through surface-wave suppression. In addition, the radiation patterns of the EBG-loaded antenna remained almost the same as for the unloaded antenna, with a 1 dB increase in antenna gain. Finally, EBG-loaded and simple 2 × 4 waveguide-slot-array antennas were fabricated, and simulation results were compared with measurements, with good agreement. As a key feature of this approach, a planar waveguide-slot-array antenna could be constructed by designing a linear antenna and then forming an array from multiples of the antenna, without the need for any new design, by imposing the EBG structure to reduce the mutual coupling between the adjacent waveguides.

Miniaturization and isolation improvement of a multiple‐patch antenna system using electromagnetic bandgap structures

AbstractIn this article, a compact multielement antenna system composing of microstrip patch antennas is designed by using electromagnetic bandgap (EBG) structures. Two distinct EBG structures are designed to achieve the two objectives of miniaturization and suppression of interelement coupling due to surface waves in a multiantenna system. By embedding an EBG array operating in the slow‐wave region, the area of the microstrip patch antenna is reduced by 67.48%. To alleviate the resulting increased back radiation, a second EBG structure is designed to surround the miniaturized patch antenna and close to 8 dB improvement in the front‐to‐back lobe ratio is achieved. As well, the second EBG design is included in a 2 × 2 multiantenna system to suppress interelement coupling. It is found that the coupling is reduced significantly when utilizing the proposed EBG rings. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1609–1612, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27621

Ultra-wideband bandpass filter with a notch band using EBG array etched ground

A novel ultra-wideband (UWB) bandpass filter (BPF) with a notch band is proposed and implemented. The filter is realized by using a high-pass filter (HPF) and an array of multiband electromagnetic bandgap (EBG) cells etched on the ground of a 50-Ω microstrip line. The first and third stopband of the designed EBG array generate sharp falling edges at each side of the passband of the UWB BPF, whereas the second stopband creates a desired notch response. As it is the passband of the designed EBG array at lower frequency, a HPF is involved. The proposed filter was successfully designed, simulated, and fabricated. The measured results show that the proposed BPF has a wide bandwidth from 3.8 to 10.1 GHz with a notch response centered at 5.1 GHz. Both simulated and measured results are described. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1290–1293, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25978

Ultra-Wideband Bandpass Filter with a Notch Band Using EBG Array Etched Ground

A novel ultra-wideband (UWB) bandpass filter (BPF) with a notch band is proposed and implemented. The filter is realized by using a high pass filter (HPF) and an array of multiband electromagnetic bandgap (EBG) cells etched on the ground of a 50 Ω microstrip line. The first and third stopband of the designed EBG array generate the edges at each side of the passband of the UWB BPF, while the second stopband creates a very sharp notch response. Since it is the passband of the designed EBG array at lower frequency, a HPF is involved. To the authors' knowledge, we present for the first time a sharp notch band generated by using an EBG array in UWB BPF. The proposed filter was successfully designed, simulated and fabricated. The measured results show that the proposed BPF has a wide bandwidth from 3.8 GHz to 10.1 GHz with a notch response centered at 5.1 GHz. Both simulated and measured results are described.

Analysis and Design of Waveguide Slot Antenna Array Integrated With Electromagnetic Band-Gap Structures

Utilization of electromagnetic band-gap (EBG) structures becomes more attractive in the electromagnetic and antenna community. This letter investigates the performance of a waveguide slot antenna array integrated with mushroom-like EBG structures. Some novel and efficient EBG array configurations are proposed, and a waveguide broadside resonant slot array of 5 times 5 elements was designed, built and tested. The tradeoffs and design considerations of EBG structures are discussed to obtain optimum performance