Uniplanar 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 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.

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.

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.

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.

Flexible Fractal Electromagnetic Bandgap for Millimeter-Wave Wearable Antennas

This letter presents a novel design of a uniplanar compact electromagnetic bandgap (EBG) for millimeter-wave wearable antennas. The unit cell of the EBG has a flexible fractal design with self-similar window-like structure, which can be easily fabricated at millimeter scale. The fabricated EBG is a 3 × 3 cell array laser-cut from adhesive copper foil on polyester fabric substrate. Results show that the gain and −10 dB bandwidth of a wearable coplanar waveguide (CPW) antenna backed by the proposed EBG are improved by 3 dB and 40%, respectively, across the frequency range from 20 to 40 GHz. Backward radiation is also decreased by 15 dB, significantly reducing the potential health risk posed by the radiating antenna to the human wearer. Furthermore, on-body measurements show that the CPW-EBG antenna performances are not highly sensitive to human body proximity.

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.

Miniaturized curved slotted patch antenna over a fractalized EBG ground plane

In this paper, a miniaturized coaxial feed curved-slotted microstrip patch antenna over a fractalized uniplanar compact electromagnetic bandgap (F-UC-EBG) ground plane is proposed and investigated. Compact size is achieved by cutting the curved slots along the orthogonal directions of the patch radiator. The curved-slotted microstrip patch antenna is 38.30% miniaturized as compared with the conventional microstrip patch antenna resonating at 2.38 GHz. Furthermore, the ordinary ground plane of the curved slotted patch antenna is replaced by the F-UC-EBG ground plane. Due to the slow wave phenomenon created in the F-UC-EBG structure and the better impedance matching at the lower frequency further miniaturization and improved performance are obtained. The proposed antenna shows 74.76% miniaturization as compared with the conventional microstrip patch antenna resonating at 1.57 GHz and has 2.61% 10-dB fractional bandwidth, 1.49 dB gain, and 81.59% radiation efficiency. The proposed antenna is fabricated on a low-cost FR4 substrate having an overall volume of 0.184λ0 × 0.184λ0 × 0.0236λ0 at 1.57 GHz GPS band. The measured and simulated results are in good agreement and predicting appropriateness of the antenna in portable and handheld communication systems for GPS applications.

Millimeter-Wave Compact EBG Structure for Mutual Coupling Reduction Applications

A new millimeter-wave (MMW), electromagnetic band-gap (EBG) structure is presented. The proposed EBG structure without the use of metallic vias or vertical components is formed by etching two slots and adding two connecting bridges to a conventional uniplanar EBG unit-cell. The transmission characteristics of the proposed EBG structure are measured. Results show that the proposed EBG structure has a wide bandgap around the 60 GHz band. The size of the proposed EBG unit-cell is 78% less than a conventional uniplanar EBG, and 72% less than a uniplanar-compact EBG (UC-EBG) operating at the same frequency band. Moreover, and despite the fabrication limitations at the 60 GHz band, the proposed EBG unit-cell provides at least 12% more size reduction than any other planar EBG structures at microwave frequencies. Its enhanced performance and applicability to reduce mutual coupling in antenna arrays are then investigated. Results show a drastic decrease in the mutual coupling level. This EBG structure can find its applications in MMW wireless communication systems.

Bandwidth and gain enhancement of optically transparent 60-GHz CPW-fed antenna by using BSIS-UC-EBG structure

A method in terms of bandwidth and gain enhancement is presented for optically transparent coplanar waveguide fed (CPW-Fed) antenna, which supports unlicensed 60GHz band (57–66GHz) applications. The original antenna and mesh antenna in [8] were designed on a transparent material that is made of a 0.2-mm-thick fused silica 7980 Corning substrate (ɛr: 3.8 and tan δ: 0.0001). However, the peak gains of −5.3 and −5.4dBi at 60GHz of those antennas can be further improved. Thus, in this paper, a novel bidirectional symmetric I-shaped slot uniplanar compact electromagnetic band-gap (BSIS-UC-EBG) structure with a reflection phase band of 58.0–62.1GHz is proposed to improve antenna performance. Based on this BSIS-UC-EBG structure, both transparent BSIS-UC-EBG antenna and transparent mesh BSIS-UC-EBG antenna with enhanced properties are presented and discussed. The analysis results show that the impedance bandwidth (the peak gain) of transparent BSIS-UC-EBG antenna and transparent mesh BSIS-UC-EBG antenna are enhanced to 36.6% (4.7dBi) and 44.7% (5.8dBi), respectively. In addition, we also discuss the comparison of radiation patterns at 60GHz, and the results illustrate that the radiation patterns are basically identical.

A NOVEL UNI-PLANAR COMPACT EBG STRUCTURE

The radiation and propagation characteristic can be improved by the microstrip structure of the electromagnetic band-gap, which is becoming miniaturized today. In order to reduce the in∞uence to the width of the band-gap brought by the miniaturization of the UC-EBG structure, a novel UC-EBG structure is brought out. The band-gap width is guaranteed, meanwhile, the unit length is reduced to 0:1‚g. Results of measurement indicate that this structure is efiectively miniaturized, has an excellent performance, and can be used in the antenna or microwave circuit flelds. The advancement in the wireless communication technology demands highly e-cient and portable devices. So, for the wireless devices, compactness is an attractive feature. But in a compact device a very small space is required to share by various radiation sources. In the planar antenna and circuit technology, mutual coupling between these sources increases. Also, noise level of the system increases, and electromagnetic interferences (EMI) become signiflcant. These efiects degrade the system performances. Excitation of surface wave inside the substrate material of planar circuits afiects the system negatively. To speed up any devices, mutual coupling reduction and suppression of unwanted noises are very important. Electromagnetic band-gap (EBG) structure, which is a periodic structure composed of metal and medium. EBG can show band rejection characteristics when propagating electromagnetic wave. Results of previous researches indicate that the EBG structure can improve the performance of telecommunication systems in many aspects (1{9). A novel Uni-planar Compact EBG (UC-EBG) structure is designed in this letter. This structure is small in size and suitable for portable and compact telecommunication systems. The results of simulation and actual measurement indicate that this UC-EGB structure has a good band-gap characteristic, with a much smaller size than other UC-EGB structures.

Compact multiband printed-IFA on electromagnetic band-gap structures ground plane

Fourth mobile generation requiring of multistandard operating handsets of small physical size as well as increasing demand for higher data rates.Compact multiband printed inverted-F antennas (IFA) for available wireless communications are proposed in this article. New design of printed IFA based on uniplanar compact electromagnetic band gap (EBG) concept is proposed. A printed-IFA with L-loaded shaped over artificial ground plane is designed as the main antenna to cover the GSM, LTE, UMTS, Bluetooth, and WLAN. The multiband is created by means of an EBG structure that is used as a ground plane. Different shapes of uniplanar EBG as ring, split ring resonator, and spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with size of 35 × 45 mm2, which is suitable for most of the mobile devices. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1670–1676, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27633

Compact multiband printed-IFA on electromagnetic band-gap structures for wireless applications

Fourth generation mobiles require multi-standard operating handsets with small physical size as well as increasing demand for higher data rates. Compact multi-band printed inverted-F antennas (IFA) for available wireless communications are proposed in this paper. New design of printed IFA based on uniplanar compact electromagnetic band-gap (EBG) structure concept is proposed. A printed-IFA with L-load shaped over an artificial ground plane is designed as the main antenna to cover most wireless applications such as GSM, LTE, UMTS, Bluetooth, Wimax, and WLAN. The multi-band is created by means of an EBG structure that is used as a ground plane. Different shapes of uniplanar EBG such as ring, split ring resonator, and spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with size of 35 × 45 mm2, which is suitable for most of the mobile devices.

Compact Multiband Printed IFA on Electromagnetic Band-Gap Structures Ground Plane for Wireless Applications

The fourth mobile generation requires of multistandard operating handsets of small physical size as well as has an increasing demand for higher data rates. Compact multiband printed inverted-F antennas (IFAs) for available wireless communications are proposed in this paper. A new design of a printed IFA based on a uniplanar compact EBG concept is proposed. An L-loaded printed IFA shaped over an artificial ground plane is designed as the main antenna to cover the GSM, LTE, UMTS, bluetooth, and WLAN. The multi-band is created by means of an electromagnetic band-gap (EBG) structure that is used as a ground plane. Different shapes of uniplanar EBG as ring, split ring resonator, and a spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with a size of 35×45 mm2, which is suitable for most of the mobile devices.

A POLE AND AMC POINT MATCHING METHOD FOR THE SYNTHESIS OF HSF-UC-EBG STRUCTURE WITH SIMULTANEOUS AMC AND EBG PROPERTIES

The relationship between the re∞ection phase curve and the dispersion curve of a H-shaped slot fractal uniplanar compact electromagnetic bandgap (HSF-UC-EBG) structure is investigated in this paper. It is demonstrated numerically and theoretically that the pole (located at phi = 180 degrees) of the re∞ection phase curve is related to the EBG location of the dispersion curve. More speciflcally, the pole is always located in the bandgap and the frequency shift characteristics of the pole and the EBG location are the same. Therefore, locations of the artiflcial magnetic conductor (AMC) and EBG can match with the AMC point and the pole, respectively. By realizing and making appropriate use of this, we can tailor the AMC and EBG locations to coincide in the frequency region only by reducing the spectral distance (d) between the AMC point and the pole. This method can improve the computational e-ciency signiflcantly. Parametric studies have been performed to obtain guidelines for reducing d. Finally, an example to design HSF-UC-EBG structure with simultaneous AMC and EBG properties by using this technique is presented with detail steps.

Wideband uniplanar compact electromagnetic bandgap structure with diagonal connecting elements

A wideband uniplanar compact electromagnetic bandgap structure with diagonal connecting elements (UC-DEBG) is proposed. Compared with a conventional uniplanar compact electromagnetic bandgap (UC-EBG) structure of similar dimensions with horizontal and vertical connecting elements, the UC-DEBG structure significantly increases the equivalent inductance while decreases the equivalent capacitance, resulting in a much wider bandgap. Dispersion diagram method was used to calculate and compare bandgaps of both structures. Bandstop filters using each structure were simulated and fabricated to demonstrate the effectiveness of the proposed structure. Larger bandgap (31%) was achieved from the UC-DEBG structure over the conventional UC-EBG structure. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:979–983, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26736

A NOVEL COMPACT SPLIT RING SLOTTED ELECTROMAGNETIC BANDGAP STRUCTURE FOR MICROSTRIP PATCH ANTENNA PERFORMANCE ENHANCEMENT

A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper. The structure is realized by inserting split- ring slots inside two reversely connected rectangular patches, which is known as a split-ring slotted electromagnetic bandgap (SRS-EBG) structure. The bandgap properties of the EBG structure are examined by the suspended microstrip line and flnite element methods (FEM). The achieved bandgaps have widths of 4.3 (59.31%) and 5.16GHz (38.88%), which are centered at 7 and 13GHz, respectively. The SRS-EBG is applied to enhance the performance of a single-element microstrip patch antenna (at 7GHz) and a two-element array (at 13GHz) conflguration. A wider bandwidth is obtained with a better re∞ection coe-cient level for the single element antenna; a reduction in mutual coupling of more than 20.57dB is obtained for the array design. In both cases, the gain and radiation characteristics are improved. The results are verifled by measuring the fabricated lab prototype, and a comparison with the computed results showed good agreement.