Compact Electromagnetic Bandgap Structure Research Articles

Curvature-Adaptive Compact Triple-Band Metamaterial Uniplanar Compact Electromagnetic Bandgap-Based Printed Antenna for Wearable Wireless and Medical Body Area Network Applications

A novel, compact, monopole apple-shaped, triple-band metamaterial-printed wearable antenna backed by a uniplanar compact electromagnetic bandgap (UC-EBG) structure is introduced in this paper for wearable wireless and medical body area network (WBAN/MBAN) applications. A tri-band UC-EBG structure has been utilized as a ground plane to minimize the impact of antenna radiation on the human body and improve antenna performance for the proposed wearable antenna. Metamaterial triangular complementary split ring resonators (TCSRRs) are incorporated into the antenna and UC-EBG structure, resulting in a compact UC-EBG-backed antenna with an overall size of 39 × 39 × 2.84 mm3 (0.41 λg × 0.41 λg × 0.029 λg). The printed textile antenna operates at 2.45 GHz for the wireless local area network (WLAN), 3.5 GHz for 5G new radio (NR), and 5.8 GHz for the industrial, scientific, and medical (ISM) bands with improved gain and high-efficiency values. Furthermore, the performance of the antenna is analyzed on the human body, where three models of curved body parts are considered: a child’s arm (worst case) with a 40 mm radius, an adult’s arm with a 60 mm radius, and an adult’s leg with a 70 mm radius. The results demonstrate that the proposed antenna is an attractive candidate for wearable healthcare and fitness monitoring devices and other WBAN/MBAN applications due to its compact size, high performance, and low SAR values.

ENHANCING WEARABLE AND MEDICAL CONNECTIVITY: A NOVEL PRINTED TRIPLE-BAND METAMATERIAL ANTENNA FOR WBAN/MBAN APPLICATIONS

This paper presents a novel, compact, monopole apple-shaped, and triple-band metamaterial printed antenna for wireless body area network (WBAN) and medical body area network (MBAN) applications. The antenna is backed by a tri-band uniplanar compact electromagnetic bandgap (UC-EBG) structure that acts as a ground plane and incorporates metamaterial triangular complementary splitring resonators (TCSRRs). The proposed printed textile antenna operates at 2.45 GHz for wireless local area network (WLAN), 3.5 GHz for 5G new radio (NR), and 5.8 GHz for industrial, scientific, and medical bands. Implementing the UC-EBG structure resulted in a 99% decrease in the specific absorption rate (SAR) values over 1 g and 10 g of tissues and achieved gains of 5.45, 6.09, and 7.63 dBi at 2.45, 3.5, and 5.8 GHz, respectively. Due to its high performance, low SAR values, and compact size of 39 × 39 × 2.84 mm<sup>3</sup> (0.41 λ<sub>g</sub> × 0.41 λ<sub>g</sub> × 0.029 λ<sub>g</sub> ), the proposed antenna is an attractive candidate for wearable healthcare, fitness monitoring devices, and other WBAN/MBAN applications.

Wideband and High-Gain Wearable Antenna Array with Specific Absorption Rate Suppression

In this paper, a wideband and high-gain antenna array with specific absorption rate suppression is presented. By adopting the wideband monopole antenna array and the uniplanar compact electromagnetic band gap (UC-EBG) structure, the proposed wearable antenna array can realize a high gain of 11.8–13.6 dBi within the operating band of 4.5–6.5 GHz. The sidelobe level of the proposed wearable antenna array is less than −12 dB, and the cross polarization in the main radiation direction is less than −35 dB. Benefiting from the UC-EBG design, the specific absorption rate is suppressed effectively, guaranteeing the safety of the proposed antenna array to the human body. The proposed antenna array is processed and tested, and the measurement results show good agreement with the simulation results.

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.

Miniaturized four-port UWB MIMO antennas with triple-band rejection using single EBG structures

AbstractThis research paper introduces a ultra-wideband (UWB) multiple input multiple output (MIMO)/diversity antenna with three rejected bands using one compact electromagnetic band gap (EBG) structure. The suggested EBG structure rejects three bands at WiMAX, WLAN, and the X-band within the passband of the UWB antenna. To achieve compactness in the conventional EBG structure, two via and square slots are introduced. This structure contributes to better impedance matching by using tapered feedline and slots in the radiating patch. To improve the isolation among all four compact UWB monopoles, decoupling strips are extended from the ground plane. Furthermore, the |S21| is below 17 dB in between the antenna elements and the envelope correlation coefficient is below 0.5, which are tolerable values within the UWB range. Furthermore, different MIMO/diversity characteristics are also discussed. An FR-4 substrate with dimensions of 38 × 45 × 1.6 mm3 is used for the fabrication of the suggested structure.

Compact stack EBG structure for enhanced isolation between stack patch antenna array elements for MIMO application

AbstractIn this research article, a compact wideband stack patch antenna array integrated with compact stack electromagnetic band gap (EBG) structure for multiple input multiple output (MIMO) application is proposed. The wide resonance bandwidth is achieved at 2.45 GHz band by stack arrangement of compact meander line slot driven and parasitic patch elements. The isolation bandwidth is matched with resonance bandwidth with the design of a compact stack L slot EBG structure. The polarization diversity and three-layer EBG structure ensure an enhancement in isolation level. To validate the performance of the proposed stack antenna array, a prototype was fabricated and tested for different MIMO parameters. The measured result confirms the effectiveness of the proposed antenna array in a diverse MIMO environment.

Design of compact triple band-notched UWB MIMO antenna with TVC-EBG structure

In this editorial, a compact two element Ultra Wide Band Multiple Input Multiple Output (UWB MIMO) antenna with triple-band notch characteristics is presented. A single Two Via Compact Electromagnetic Band Gap (TVC-EBG) structure is used to achieve triple-band notches at WiMAX, WLAN, and X Band. An inverse L-shaped stub is inserted in the ground plane of the antenna to diminish mutual coupling amid antenna elements. Isolation and Envelope Correlation Coefficient (ECC) is less than −15 dB and 0.015, respectively. The diversity properties like Total Active Reflection Coefficient (TARC), Diversity Gain (DG) are less than −10 dB and greater than 9.95 dB respectively. The proposed antenna is designed using a low-cost FR4 substrate with overall dimensions of 21 × 36 × 1.6 mm3.

Design of Reconfigurable Antenna Using MSF-EBG Structure to Improve Performance Parameters

A wide band gap slot fractal uniplanar compact electromagnetic band gap (UC-EBG) structure is designed based on the third iteration of Moore space filling geometry (MSF-UC-EBG). By changing the dimensions of the EBG structure, different band gap characteristics can be obtained. This structure (named as FR4_EBG) is simulated using Computer Simulation Technology, fabricated and measured. Furthermore, the FR4_EBGs are integrated with a coplanar waveguide fed stepped-impedance resonator (SIR) antenna to research MSF-UC-EBG’s microwave application. After integration, the overall performance of SIR antenna is significantly improved. The proposed MSF-UC-EBG can be easily integrated with low-frequency applications such as GSM, PCS, Bluetooth, Wi-max, and Wi-Fi. Simulated results of the reconfigurable antenna by using switch (P-I-N diode or RF-MEMS) are also observed. This antenna operates for two different frequencies, 1.568 GHz when the switch is open and 2.5 GHz when the switch is closed.

Microstrip monopole antenna with a novel UC‐EBG for 2.4 GHz WBAN applications

A microstrip monopole antenna backed with a novel uniplanar compact electromagnetic bandgap (UC-EBG) structure for 2.4 GHz wireless body area network applications is proposed here. The proposed antenna has a size reduction of 50% when the number of EBG array is optimised from 3 × 4 to 2× 3, while the radiation performance is almost invariable at the same time. The operating frequency band under different conditions has the capability of covering the 2.4–2.4835 GHz industrial, scientific, and medical band. Due to the addition of 2×3 UC-EBG on the back, the radiation patterns become unidirectional, and the measured average gain increases from 2.1 to 5.6 dB. Meanwhile, the cross-polarisation of the monopole antenna can be suppressed prominently by the EBG array. The simulated specific absorption rate values are 0.0536 W/kg under 1 g standard and 0.0296 W/kg under 10 g standard, which are far below the limitation of USA and Europe. These results can manifest the reliable wearable performance of the proposed antenna.

A Compact EBG Structure With Etching Spiral Slots for Ultrawideband Simultaneous Switching Noise Mitigation in Mixed Signal Systems

In this paper, a compact electromagnetic bandgap (EBG) structure for mitigating simultaneous switching noise (SSN) in high-speed mixed signal systems is proposed. Only one spiral slot is etched on the square patch, which constitutes the unit cell of the presented EBG pattern. The equivalent circuit model is developed to interpret the mechanism of the proposed power distribution network structure. By etching slot in the square patch of the EBG pattern, a high impedance is provided for prohibiting the SSN propagation. Furthermore, the capacitance is increased correspondingly, which can enlarge the bandwidth of the SSN suppression performance. An ultrawideband SSN suppression property is achieved from 0.35 to 20 GHz under the suppression level of −40 dB. In comparison with the traditional multiturns spiral EBG structure, not only the bandwidth but also the rejection level can be improved significantly with the presented design. Moreover, the SI performance is investigated, and the corresponding improvement measure is presented. Good agreements are observed between the simulation and measured results.

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.

Wideband Wide-Scanning Phased Array in Triangular Lattice With Electromagnetic Bandgap Structures

A phased array in a triangular lattice, with a large element spacing, wide band, and wide scan angle, is investigated in this letter. The array is designed based on a connected backed-cavity antenna element. Scan blindness is observed for this triangular lattice array when the beam scans in the E-plane due to large element spacing, which provides a suitable propagation condition for the leaky surface waves in the array aperture. Therefore, compact electromagnetic bandgap (EBG) structures are loaded in the array element to suppress the leaky surface waves and then remove the E-plane scan blindness for the largest impedance bandwidth. The bandwidths close to the theoretical values are achieved as the beam is scanned in the E- and H-planes, for the given element spacing. The validity of design is verified by fabricating a 13 × 5 prototype, the measured results are in good agreement with the full-wave simulations.

Hybrid Isolator for Mutual-Coupling Reduction in Millimeter-Wave MIMO Antenna Systems

A novel millimeter-wave (MMW) hybrid isolator is presented to reduce the mutual-coupling (MC) between two closely-spaced dielectric resonators (DR) antennas at 60 GHz. The proposed hybrid isolator consists of a combination of a new uni-planar compact electromagnetic band-gap (EBG) structure and an MMW choke absorber. The design of the proposed EBG unit-cell is based on the stepped-impedance resonator (SIR) technique. The results show that the proposed EBG structure provides a wide frequency bandgap in the 60 GHz band with miniaturization factors of 0.79 and 0.66 compared to conventional uni-planar EBG and uni-planar compact (UC-EBG) structures, respectively. The proposed EBG is then placed between two Multiple-Input Multiple-Output (MIMO) DR antennas to reduce the MC level. As a result, an average of 7 dB level reduction is obtained. To further reduce the MC level, a thin MMW choke absorber wall is mounted vertically between the two DR antennas and above the EBG structure. An average of 22 dB MC reduction is achieved over the suggested bandwidth while maintaining good radiation characteristics. The measured isolation of the prototype antenna varies from -29 to -49 dB in the frequency range from 59.3 to 64.8 GHz. In fact, the proposed hybrid isolator outperforms other hybrid isolation techniques reported in the literature.

Mutual coupling reduction and gain enhancement in patch array antenna using a planar compact electromagnetic bandgap structure

This research work presents a planar compact electromagnetic bandgap (EBG) structure with the potential to reduce the mutual coupling between the elements of a microstrip antenna array. The proposed structure is investigated at 5.59 GHz, which is the centre frequency of the wireless local area network band. To achieve the highest radiation performance for microstrip antenna arrays, with minimal inter-element spacing and mutual coupling, different unit cell arrangements were considered along with two adjacent patch elements. The simulations and measurement results for the proposed arrangements indicate that the mutual coupling tends to diminish significantly. For instance, when adjacent patches are spaced by 0.4 λ , the mutual coupling improves by ~25 dB. For the particular spacing of 0.4 λ , it is favourably observed that the proposed EBG cells can also improve the antenna gain by ~2.5 dB. Such improvements can be attributed to the compactness of the cells (~ λ /8 × λ /10) and their remarkable ability to suppress the surface waves.

A Compact and Multi-Stack Electromagnetic Bandgap Structure for Gigahertz Noise Suppression in Multilayer Printed Circuit Boards

In modern printed electronics, the performances of a circuit and a device are severely deteriorated by the electromagnetic noise in the gigahertz (GHz) frequency range, such as the simultaneous switching noise and ground bounce noise. A compact and multi-stack electromagnetic bandgap (CMS-EBG) structure is proposed to suppress the electromagnetic noise over the GHz frequency range with a short distance between a noise source and a victim on multilayer printed circuit boards (MPCBs). The original configuration of the stepped impedance resonators is presented to efficiently form multiple stacks of EBG cells. The noise suppression characteristics of the CMS-EBG structure are rigorously examined using Floquet-Bloch analysis. In the analysis, dispersion diagrams are extracted from an equivalent circuit model and a full-wave simulation model. It is experimentally verified that the CMS-EBG structure suppresses the resonant modes over the wideband frequency range with a short source-to-victim distance; thus, this structure substantially mitigates GHz electromagnetic noise in compact MPCBs.

Compact ( $\lambda /45$ -Sized) Electromagnetic Bandgap Structures With Stacked Open-Circuit Lines

This letter introduces double layer layouts of open-circuit lines into the electromagnetic bandgap (EBG) structures to enable changing the shunt circuit of the parallel plate waveguide to inductance in compact spaces. That is, compact EBG structures were achieved. The EBG structures, fabricated using standard fabrication processes and using a low-cost substrate (flame retardant type 4), enable a 1-mm-order size for a 2.4-GHz BG. The size is less than 1/10 of the conventional mushroom structures and corresponds to 1/45 of a substrate wavelength. This compact as well as low-cost EBG structure is promising for noise suppression applications of power distribution networks, especially for wireless products with high-density circuit boards.

EBG Structures for Reduction of Mutual Coupling in Patch Antennas Arrays

An important issue in antenna array design is reduction of mutual coupling. In square microstrip antennas this reduction can be achieved by using electromagnetic band-gap (EBG) structures. They can help in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. In this paper, we analyze the isolation properties of different EBG structures are compare them in antennas arrays by simulations. A new configuration of a planar compact electromagnetic bandgap structure is investigated. Compared to the conventional EBG (mushroom structure), a size reduction of 67.2% is achieved. Simulation results show that a significant value of mutual coupling reduction, more than 6 dB, can be obtained by using the proposed structure.

Isolation Enhancement in Patch Antenna Array With Fractal UC-EBG Structure and Cross Slot

A compact patch antenna array with high isolation by using two decoupling structures including a row of fractal uniplanar compact electromagnetic bandgap (UC-EBG) structure and three cross slots is proposed. Simulated results show that significant improvement in interelement isolation of 13 dB is obtained by placing the proposed fractal UC-EBG structure between the two radiating patches. Moreover, three cross slots etched on the ground plane are introduced to further suppress the mutual coupling. The design is easy to be manufactured without the implementation of metal vias, and a more compact array with the edge-to-edge distance of 0.22 λ0 can be facilitated by a row of fractal UC-EBG, which can be well applied in the patch antenna array.

A Wide Band-Gap Slot Fractal UC-EBG Based on Moore Space-Filling Geometry for Microwave Application

A wide band-gap slot fractal uniplanar compact electromagnetic band-gap (UC-EBG) structure based on the third iteration of Moore space-filling geometry (MSF-UC-EBG) is proposed. By changing the dimensions of the structure and the substrate materials, different band-gap characteristics can be obtained. In this letter, we design two kinds of MSF-UC-EBG structures, fabricated on FR4 and RogersRO3010 substrate, denoted as FR4_EBG and Rogers_EBG, respectively. Two wide band-gaps of 1.43–5.89 GHz (relative bandwidth 121.8%) and 1.09–4.57 GHz (relative bandwidth 122.9%) are achieved when five MSF-UC-EBG unit cells are arranged periodically. The measurements agree well with simulations. Furthermore, the aforementioned FR4_EBGs are integrated with a coplanar-waveguide-fed stepped-impedance resonator (SIR) antenna to research the MSF-UC-EBG's microwave application. After integration, bandwidth performance of SIR antenna is significantly improved. Comparisons of measured bandwidth of SIR antenna with and without FR4_EBGs are made, respectively.

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.