Compact Electromagnetic Bandgap Research Articles

Ultrawide-band Wearable Antenna with Uniplanar Compact Electromagnetic Band Gap

Ultrawide-band technology, commonly known as UWB, sends data over a wide frequency range for many applications. WBAN applications use wearable antennas because they have flexible materials and are suitable for telemedicine technology and have many advantages such as small size, lightweight, able to work at a wide enough frequency, easy fabrications, and affordable costs. In this research, the hexagonal patch ultrawide-band monopole planar wearable antenna was designed using Cordura Delinova 2000 textile material for the substrate and copper tape for the groundplane and patch. The Uniplanar Compact Electromagnetic Band Gap (UC-EBG) as a metamaterial was added to the design of the monopole planar antenna in this final project which aims to improve antenna parameters, increase efficiency, and reduce the effects of radiation on the body. From the measurement results on the antenna with the addition of the UC-EBG structure at the bottom of the patch, it produces a 6% fractional bandwidth increase and able to work in the frequency range of 3-10 GHz off-body conditions and 2-11 GHz on-body conditions. In the SAR test at 45 mm, it was found that the value decreased from previously 1.535 W/Kg to 1.31 W/Kg at a frequency of 3.5 GHz and previously from 1.421 to 1.267 W/Kg at a frequency of 5 GHz on a wrist phantom object which is a good value for SAR. The resulting increase in antenna gain after the addition of the UC-EBG structure. The radiation pattern on the antenna is bidirectional.

Compact hybrid EBG microstrip antenna for wearable applications

Abstract A novel strip line fed, circularly polarized (CP), annular slotted dual band antenna using hybrid electromagnetic band gap (EBG) structure for Global Positioning System (GPS) has been herein designed, analyzed, and investigated for wearable applications. Adjusting the radii of the annular slots on the radiating patch excellent circular polarized (CP) radiation and impedance matching is achieved. The design demonstrates Kapton based flexible, robust, and low-profile solution with permittivity of 3.4 to meet the requirements of wearable applications. Due to the high losses of the animal body, the electromagnetic band gap (EBG) structure is used to reduce back radiation and the effect of frequency detuning. The proposed antenna structure also enhances the front-to-back ratio (FBR) by 10 dB. This antenna with dimensions 0.56λ 0 × 0.4913λ 0 × 0.002λ 0 analyzed using a flexible Kapton substrate. Optimized hybrid EBG structure provides an excellent Specific Absorption Rate (SAR) along with all other antenna parameters, within acceptable for GPS-based wearable applications at 1.13 GHz and 1.157 GHz frequency band. Therefore the proposed antenna is a suitable candidate for GPS-based tracking and wireless body area network (WBAN) applications. The proposed antenna was also tested upon fabrication and the measured results agree with simulated results.

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.

Compact bio‐inspired dual‐band uniplanar electromagnetic bandgap‐backed antenna for wearable applications

A compact bio-inspired electromagnetic bandgap integrated wearable antenna (Bio-EBG-iwA) is proposed in this work. The Bio-EBG-iwA is based on the hybridization of semi-Vitis vinifera leaf-shaped patch, asymmetric feedline, reflected G-shaped slot, partial ground, and a stub on the ground plane. The antenna is built on the locally made textile material called Aso-oke (Alari) with permittivity and a loss tangent of 1.43 and 0.019, respectively. The dimension of the proposed antenna is 0.2 λ g × 0.1 λ g × 0.0089 λ g (22 mm × 12 mm × 0.7 mm) at 2.45 GHz. Despite its compactness, the gain of −0.48 and 2.5 dBi are achieved at 2.45 and 5.7 GHz respectively without electromagnetic bandgap (EBG). A dual-band textile-based uniplanar compact electromagnetic bandgap (UC-EBG) is introduced to create isolation between the human tissue and the antenna. The dual-band UC-EBG is realized through the use of a modified slitted-square ring (MSSR) and the 90° rotated H-shaped patch on Aso-oke (Alari) with a thickness of 2.1 mm. The periodicity of the proposed UC-EBG is 34.5 mm. The antenna is placed on a 2 × 2 array of the proposed UC-EBG separated by a 3 mm foam thickness. The radiation efficiency of 88.97% and 79.85% are achieved at 2.45 and 5.7 GHz respectively. The gain of the proposed UC-EBG integrated antenna increased from −0.48 and 2.5 dBi to 5.9 and 10.7 dBi at 2.45 and 5.7 GHz, respectively. The front-to-back ratio (FBR) of 26.3 dB is achieved with the use of UC-EBG. The use of UC-EBG results in a 98.31% and 99.4% reduction in average SAR at 2.45 and 5.7 GHz, respectively. The off-body and on-body performance analysis of the proposed UC-EBG integrated antenna show that the proposed EBG integrated antenna (Bio-EBG-iwA) is a suitable candidate for wearable application. To the best of our knowledge, this is the most compact wearable antenna with suitable gain, radiation efficiency, and high FBR. In addition, our proposed UC-EBG shows that slitting is an effective way of miniaturizing the EBG structure.

Small UWB antenna with two stop bands by a compact EBG cell loaded with new open meander slots

AbstractIn this paper, a small ultra-wideband (UWB) antenna with two stop bands by a compact electromagnetic bandgap (EBG) cell loaded with two new open meander slots is presented. With the coupling of the EBG cell to the feedline, the stop bands are formed. The designed EBG cell is a mushroom type that has the advantages of being able to independently control the stop bands, high responsiveness selectivity of stop bands, easy switching, the need for fewer EBG cells, and low impact on the working characteristics of the antenna. To have a better understanding of the proposed EBG mechanism, characteristic mode analysis is used. The size reduction of the suggested antenna is obtained by halving the reference antenna relative to the axis of symmetry. The measurement results for −10 dB adaptation are from 2.73 to 13 GHz with stop bands at 3.51 GHz (12.9%) and 5.34 GHz (14.1%). The radiation behavior of the minimized antenna is similar to that of a reference antenna. Minimized UWB antenna with transmission function and group delay with small variations in the operating frequency range is suitable for small multiple-input and multiple-output (MIMO) and diversity systems.

Analysis and Development of an Efficient Cross-Slot Loaded Compact Electromagnetic Band Gap Antenna

This paper is devoted to a novel Electromagnetic Band Gap (EBG) single-feed circularly polarized microstrip EBG antenna with compact size proposed for C-Band applications. The antenna structure will include eight slits introduced at the boundary and the corners in the radiating square patch with a cross-slot at the center. The provided study will effectively approve the various proposed structures and interest occupied by these types of antennas in the enhancement of output parameters (gain, directivity, radiation efficiency, and bandwidth) without much affecting the operating bandwidth at C-band. At first, the concept and the realization of a directive and circularly polarized antenna using an electromagnetic band gap material whose circular polarization is generated by the structure itself is discussed. The analysis and simulation results are presented for an antenna operating at 6.1 GHz using computer Simulation Technologies (CST). Furthermore, the new compact circular polarized EBG antenna, compared to experimental results, will confirm the pre-studied goal of these kinds of antennas such as radiation efficiency, polarization purity, radiation efficiency, high directivity, and gain.

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.

Compact multiple EBG cells loaded UWB-narrowband antenna pair with high isolation for cognitive radio (CR) based MIMO applications

In this paper, a cognitive radio (CR) based multiple-input-multiple-output (MIMO) antenna element comprising of an ultra-wideband (UWB) and narrowband (NB) radiator is proposed. The antenna consists of a circular monopole to achieve UWB operation and a quarter-wavelength monopole for NB operation. The high isolation between the two radiators is obtained by accommodating multiple electromagnetic band-gap (EBG) cells and an isolating stub between the UWB and NB radiators. Multiple EBG cells of varying size are employed to obtain isolation-enhancement over the entire UWB spectrum. The proposed design exhibits high isolation, better than 25 dB over most of the UWB spectrum. Fabricated prototype was measured and compared with simulations and good agreement was obtained. The antenna also satisfied the MIMO performance metrics. The size of the antenna is 50 × 50 mm2. Proposed highly isolated MIMO antenna pair is a good candidate for multi-standard radio applications requiring wideband and narrowband antennas in the same platform.

New electromagnetic band gap antenna for multiple ultra wide band applications

This paper presents a compact multiband microstrip electromagnetic band gap (EBG) patch antenna with partial ground used for the 2nd and 3rd mode excitation, allowing multiple band resonance and control of the resonance frequencies. The electromagnetic band gap elements are inserted to improve obviously output parameters (gain directivity, return loss, maximum radiation Intensity, and radiation efficiency). Simulation and measurement results show a multiband antenna WiMAX, WLAN-band applications that can effectively cover three separated bandwidths (2.12, 3.1 and 5.41 GHz). The proposed compact antenna is grounded on a 1.6 mm-thick FR4 epoxy substrate with overall dimension of 0.305λ × 0.305λ × 0.012λ at lower frequency. The whole size of the proposed antenna with an overall area of 25 × 38 × 1.6 mm3 is maintained, and a low cross-polarization level within the operating frequency range. Electromagnetic Band Gap materials, artificially engineered structures, have the main role to improve the output performance of the patch antennas.

Printed compact asymmetric dual L‐strip fed split‐ring shaped EBG‐based textile antenna for WBAN applications

AbstractThis letter presents a design of very compact asymmetric dual L‐strip fed split‐ring shaped electromagnetic bandgap (EBG)‐based textile antenna for wireless body area networks (WBAN) applications, operating at frequency 2.45 GHz. The antenna radiator is composed of 2 × 1 array of EBG cells printed on same side of the substrate with partial ground plane to form a compact EBG surface, excited with a 50 Ω inverted L‐strip feed line. The partial ground plane with EBG cells is used to miniaturize the proposed antenna of size 40 × 20 × 0.3 mm3. The proposed compact asymmetric dual L‐strip fed wearable antenna (DLSWA) with EBG structure is fabricated on denim (jeans) substrate having dielectric constant (ɛr) 1.7 and thickness of 0.3 mm. The design of proposed antenna is optimized for Industrial, Scientific, and Medical (ISM) band (2.4‐2.48 GHz)through various parametric variations with simulated impedance bandwidth (BW) of 12.2% (2.3‐2.6 GHz) for reflection coefficient |S11| ≤ −10 dB and also exhibits stable radiation patterns with simulated peak realized gain of almost 3.5 dBi in the entire operational frequency band. The performance of proposed wearable antenna on human body is also studied and observed low specific absorption rate (SAR) value of 0.6 W/kg over 10 g of human tissues. The proposed compact asymmetric DLSWA is designed, fabricated, and tested. The simulated results of designed antenna are verified and validated with measured results which show good agreement for all radiation characteristics of proposed antenna for WBAN applications.

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 and Modeling of Hybrid Uniplanar Electromagnetic Bandgap Power Planes for Wide-Band Noise Suppression on Printed Circuit Boards

In this paper, a hybrid uniplanar compact electromagnetic bandgap (UC-EBG) design is proposed with a wide-band noise suppression in power planes of printed circuit boards (PCBs). To achieve wide-band noise suppression, the proposed hybrid UC-EBG design employs a combination of various uniplanar EBG unit cells with different sizes which have different frequency ranges of noise suppression corresponding to the size of the cells. In addition, an analytic model of the EBG unit cell composed of cavity resonant model and meander line inductance is proposed and validated by 3-dimensional field simulation and measurement. To demonstrate the proposed design, a heterogeneous group of unit cells with different sizes was selected and the noise transfer function was compared with that of a conventional UC-EBG structure. The proposed hybrid UC-EBG design is experimentally verified by noise transfer function measurement with a significant expansion of the stopband up to 478 % in comparison to the conventional uniplanar EBG designs with the same area occupation.

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.

Radiation control of microstrip patch antenna by using electromagnetic band gap

In this paper, two compact electromagnetic band gap (EBG) antennas are proposed by combining a rectangular antenna with a mushroom-like EBG structure and with a novel triple side-slotted EBG (TSSEBG). Both prototype antennas can scan the main beam in the elevation (E) (−20° < φ < 20°), (−17° < φ < 17°) and horizontal (H) (−18° < θ < 18°), (−15° < θ < 15°) planes, respectively. The main beam scanning was conducted by using band-stop and band-pass properties. The band-stop property was achieved by connecting the vias to the ground plane of the antenna, whereas the band-pass property was realized by disconnecting the same vias, thereby yielding the beam steering into the pass-band sector. Unlike usual beam steering, this technique does not suffer from gain degradation, and the gain of the main lobe is approximately stable for the steering angles. The antenna performance was enhanced due to suppress surface waves. Moreover, the number of vias was reduced significantly in the proposed TSSEBG instead of the mushroom-like EBG. The compact EBG and TSSEBG antennas have directivity (10 and 10.5) dBi, gain (9.86 and 10.16) dB, and efficiencies of 96.5% and 93%, respectively, with the operating frequency at 6 GHz.

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.

A miniaturized dual band EBG unit cell for UWB antennas with high selective notching

AbstractA high selective dual band and miniaturized electromagnetic band gap (EBG) unit cell is presented in this paper. The analysis and characterization of the new cell are explained. The modified compact EBG unit cell is based on cutting two inverted U-shaped slots inside the typical mushroom-like EBG. The modified EBG has a 70% size reduction. The dual-band functionality of the structure is confirmed by applying it in a dual-notch ultra-wideband antenna (3.1–10.6 GHz), and the notch frequencies are 5.2 and 5.8 GHz. The dual-band functionality has advantages of a highly selective bandpass between them. The antenna can suppress interference frequencies in less than 100 MHz bandwidth without affecting the antenna performance in the whole bandwidth. Presented results are addressed in terms of circuit modeling, 3D full-wave simulations, and measurements.

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.