Uniplanar Electromagnetic Bandgap Research Articles

Design of a Low Profile Archimedean Spiral Antenna using Compact Defected Ground Structure as a Reflector

In this paper, design and realisation of a low profile Archimedean spiral antenna is presented. The low profile Archimedean spiral antenna is printed on a substrate and backed by a reflector consisting of DGS. The DGS unit cell consists of a parallel combination of meander line inductors and inter-digital capacitors. This, DGS is one of the forms of electromagnetic band gap (EBG) structures providing electromagnetic band gap characteristics. It is used as a reflector with spiral antenna to achieve unidirectional radiation properties and a low profile of antenna. A modified version of uniplanar EBG cell is used as a DGS cell. This cell is used for configuration of the DGS ground plane. This ground plane is evaluated for its electrical characteristics and used as a reflector for the spiral antenna. Archimedean Spiral antenna is designed and simulated in the frequency band of 1-6GHz with DGS as a reflector. The antenna characteristics are studied for physical parameters of the antenna. These parameters are optimized for better electrical characteristics. The performance of the proposed antenna is also compared with conventional metallic (PEC) reflectors. Simulated results of an antenna are validated by measurement. Antenna height reduction of 60% is achieved compared to conventional cavity-backed spiral antennas.

Reduction of Surface Waves in Arrays using Uni-Planar EBG

Electromagnetic band gap (EBG) structures can be treated as sporadic arrangement of dielectrics. These structures will aid in the coupling reduction in arrays. In this paper, for reducing coupling between array antennas, a new arrangement of EBG structures is presented. The antenna resonates at 5.8GHz, used for wireless requirement. Here 5 × 2 EBG structures are used to reduce mutual coupling more than 20 dB. The antenna substrate dimensions are 36 mm × 68 mm × 1.6 mm. Also, the dispersion diagram was used to design EBG unit cell. In this, a uniplanar EBG configuration which is easy to fabricate without the use of vias is designed for antennas. Their use in coupling reduction of planar antennas and low-profile antenna applications is explored through an effective technique, because the information required is the dispersion diagram and reflection phase of the unit cell. Different Uniplanar-EBGs are used for optimizing current distribution on the antennas, decreasing the coupling between elements and harmonic suppression. As a result, the antenna array performance is improved and minimum coupling is less than -20 dB by using this EBG structure.

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 between elements of UWB MIMO antenna using small size uniplanar EBG exhibiting multiple stop bands

In this paper, mutual coupling reduction between elements of UWB MIMO antenna using small size uniplanar EBG is presented. Proposed UWB antenna geometry consists of two circular shaped monopole radiator swith a slot in ground plane for proper impedance matching. A UC-EBG (Uniplanar Electromagnetic Band Gap) cell of size 6.8 mm × 6.8 mm is inserted between the antenna elements in 4 × 1 array configuration to improve the isolation. Bandgap of the UCEBG is determined using dispersion diagram and suspended stripline method. The proposed antenna is fabricated on 1.6 mm thick, low cost FR4 substrate, possessing an overall size of 27.2 mm × 46 mm. The antenna has been fabricated and experimentally verified. The antenna shows simulated and measured −10 dB impedance bandwidths of 14.6 GHz (3–17.6 GHz) and14.8 GHz (3.6–17.9 GHz) respectively. UCEBG structure exhibits multiple stop bands and suppresses E-plane coupling over these bands. Isolation better than −18 dB is achieved over the complete impedance bandwidth. Radiation efficiency and peak gain of the antenna varies from 78% to 96.7% and 1.4 dB to 4 dB respectively. MIMO parameters, i.e. error correlation coefficient (ECC) better than0.018 and Total active reflection coefficient (TARC) better than −26 dB is achieved over the impedance bandwidth.

Triple band notched mushroom and uniplanar EBG structures based UWB MIMO/Diversity antenna with enhanced wide band isolation

Triple band-rejection MIMO/Diversity UWB antenna characteristics are described in this paper. Proposed antenna discards worldwide interoperability for microwave access WiMAX band from 3.3 to 3.6 GHz, wireless local area network WLAN band from 5 to 6 GHz and X-Band satellite downlink communication band from 7.1 to 7.9 GHz. Mushroom Electromagnetic Band Gap (EBG) structures helps to attain band notches in WiMAX and WLAN bands. Uniplanar plus shaped EBG structure is used for notch in X-band downlink satellite communication band. Decoupling strips and slotted ground plane are employed to develop the isolation among two closely spaced UWB monopoles. The individual monopoles are 90° angularly separated with stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing current path length. Mutual coupling magnitude of more than 15 dB is found over whole UWB frequency range. The Envelope Correlation Coefficient is less than 0.02 over whole UWB frequency range.The variations in the notched frequency with the variations in mushroom EBG structure parameters are investigated.The antenna has been designed using FR-4 substrate and overall dimensions is (64 × 45 × 1.6) mm3.

Parametric Analysis of Wearable Vialess EBG Structures and Its Application for Low Profile Antennas

Electromagnetic Bandgap (EBG) structures are one class of metamaterial with attractive properties that unavailable in nature and widely used for improving the electromagnetic performance. Its In-phase reflection frequency band is indicated as operation frequency band, whose characteristic is closely related to the parameters of EBG structure, such as patch width (w), gap width (g), substrate height (h) and substrate permittivity (e). The presence of via within EBG structure is associated with design and fabrication complexities, which led the researchers to study uniplanar EBG. These structures require no via and can easily be fabricated and integrated with RF and microwaves alication. Therefore, an investigation study on the effect of the parameters of the vialess EBG surface and some design guidelines have been obtained. An example of an antenna integrated with EBG is also studied. The result indicates that the EBG ground plane significantly improves the work efficiency of the antenna in a particular frequency band.

Compact transmit receive hybrid electromagnetic isolation in antenna array transceiver system for full duplex applications

This study presents a hybrid electromagnetic isolation mechanism in a transceiver array antenna operating at 5.8 GHz. Maximum isolation between transmitting and receiving array antennas, at a very close spacing (3 mm = 0.058 λ 0 ), and minimum mutual coupling between each array elements is achieved without antenna radiation pattern degradation. The achieved separation is equivalent to 44% size reduction compared with conventional half wavelength spacing criterion. Each of the transmitting and receiving array antennas is a four-element linear microstrip patch array antenna. The employed hybrid isolation technique is composed of defected ground structure, to minimise coupling between array elements, and uniplanar electromagnetic bandgap, to minimise the coupling between the transmitting and receiving antennas. The resulting transceiver array antenna system fulfils -35 dB mutual coupling between array elements, and 60 dB isolation between opponent transmitting and receiving array antennas. The proposed design procedures are discussed and analysed using electromagnetic full wave simulations. Results were verified through experimental measurements for reflection coefficient, mutual coupling and radiation characteristics in which a good agreement with simulated results is granted.

Notched UWB Circular Monopole Antenna Design Using Uni-Planar EBG Structures

The proposed antennas employs uniplanar Electromagnetic Band Gap (EBG) structures which are capacitively combined to antenna feed to realize band-notched designs. The benefits of uniplanar EBG structures are elimination of vias therefore it shortens fabrication procedure and makes them compatible with microwave and millimetre circuits. Two dissimilar notched UWB antennas designs with square and circular designed uniplanar EBGs are proposed. Antenna with square EBGs has a notch in c-band at frequencies 6.05 GHz -7.43 GHz. Antenna with circular EBGs has a notch in c-band at frequencies 6.23 GHz -7.68 GHz. Notch frequencies can be altered just by changing the connecting strips and gaps of EBG cells. Measured outcomes are found to be in near agreement with simulated ones.

DESIGN OF A COMPACT PATCH ANTENNA LOADING PERIODIC JERUSALEM CROSSES

A compact microstrip antenna loaded with periodic patterns etched in the ground plane is proposed. The etched patterns are Jerusalem crosses which look the same as one of the common electromagnetic band gap structures, uni-planar electromagnetic band gap. In this paper, the dielectric backed with etched ground plane is analysed in terms of metamaterial. The permittivity and permeability are derived from the simulated reflection and transmission coefficients. Then a patch is stacked on the metasubstrate, and the antenna is designed to operate at 2.4GHz. The proposed antenna has a small dimension in comparison to two other published compact antennas. Compared to the conventional patch antenna, the proposed antenna achieves a 68.38% miniaturization of the patch, and a 2.84 times impedance bandwidth broadening. Furthermore, the operating frequency of the proposed antenna can be tuned over a large range of frequencies by physically adjusting the length of the surrounding slots or by voltage adjusting of the voltage controlled tunable inductive elements. The proposed antenna is fabricated and measured. The measurement results are found to agree well with the simulation ones.

FSS Properties of a Uniplanar EBG and Its Application in Directivity Enhancement of a Microstrip Antenna

In this letter, frequency selective surface (FSS) properties of a uniplanar electromagnetic band-gap (EBG) unit cell are studied. The unit cell consists of meander-line inductor and interdigital capacitors on one side of a substrate. Simulation results indicate that the unit cell exhibits passband characteristics centered at 10.04 GHz. FSS property of the structure is verified by measurement using X-band waveguides. The measured results show passband characteristics at 9.45 GHz. A 13 × 13 array of these unit cells (FSS screen) is used as a superstrate at a distance ≈ 0.5λ 0 over a patch antenna operating at 10.8 GHz, offset from center frequency of the FSS passband. Directivity improvement of 6.95 dB is observed along 0° in the measurements of patch antenna with FSS superstrate as compared to the patch antenna without superstrate.

Equivalent Circuit Model of Resonant-EBG Bandstop Filter

ABSTRACTIn this paper, we present an equivalent circuit model of a uni-planar electromagnetic bandgap (EBG) structure. The equivalent circuit is developed by the combination of lumped element representation of distributed elements. The EBG structure is coupled to the transmission line and the coupling is modelled by a capacitor between the structure and the transmission line. The circuit simulated results match well with the electromagnetic simulation results.

A compact CPW‐FED wideband metamaterial antenna with EBG loading

ABSTRACTTwo wideband CPW‐fed metamaterial antenna structures based on CRLH resonant approach are proposed and developed in this article. Antenna‐1 is basically an asymmetric CPW‐fed antenna, comprises of meandered line inductor, which is connected between patch and one of the CPW ground plane. Antenna‐2 is modified form of Antenna‐1 where conventional uniplanar electromagnetic bandgap (EBG) structures have been incorporated to enhance bandwidth of the antenna. It has been observed that Antenna‐2 is operating at 4.84–10.64 GHz equivalent to 74.9% measured fractional bandwidth with respect to Antenna‐1 with operating frequency 5.03–8.39 GHz equivalent to 50.1% fractional bandwidth. It is demonstrated that surface waves are suppressed effectively in the extended band. The radiation patterns of the Antenna‐2 are not influenced significantly with the incorporation of EBG and offers consistent radiation patterns throughout the operational bandwidth. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2632–2636, 2015

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.

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.

Dense Dielectric Patch Array Antenna With Improved Radiation Characteristics Using EBG Ground Structure and Dielectric Superstrate for Future 5G Cellular Networks

In this paper, a new dense dielectric (DD) patch array antenna prototype operating at 28 GHz for future fifth generation (5G) cellular networks is presented. This array antenna is proposed and designed with a standard printed circuit board process to be suitable for integration with radio frequency/microwave circuitry. The proposed structure employs four circular-shaped DD patch radiator antenna elements fed by a 1-to-4 Wilkinson power divider. To improve the array radiation characteristics, a ground structure based on a compact uniplanar electromagnetic bandgap unit cell has been used. The DD patch shows better radiation and total efficiencies compared with the metallic patch radiator. For further gain improvement, a dielectric layer of a superstrate is applied above the array antenna. The measured impedance bandwidth of the proposed array antenna ranges from 27 to beyond 32 GHz for a reflection coefficient (S11) of less than -10 dB. The proposed design exhibits stable radiation patterns over the whole frequency band of interest, with a total realized gain more than 16 dBi. Due to the remarkable performance of the proposed array, it can be considered as a good candidate for 5G communication applications.

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

Wideband quasi-isotropic H-shaped slot fractal UC-EBGs with alternately arranged symmetrical unit cells

The arrangement of the alternately symmetrical unit cells of an H-shaped slot fractal uniplanar electromagnetic bandgap structure (HSF-UC-EBGs) is investigated in this study. It is shown that different bandgap characteristics can be obtained when the unit cells are arranged in different ways. Two bandgaps of 1.30–2.52 and 2.85–3.76 GHz are obtained when 5 unit cells are arranged along x direction, while a bandgap of 2.30–4.78 GHz is obtained when 5 unit cells are arranged along y direction. Therefore, one can predict that when the symmetrical unit cells and the 90° rotated symmetrical unit cells are arranged alternately, the bandgap will extend to the sum of the three bandgaps mentioned previously. Based on the study described previously, we design an ultra-wideband quasi-isotropic HSF-UC-EBGs and the measured results show that its relative bandwidth reach up to at least 105.4% GHz at 3.32 GHz.

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.

A compact uniplanar EBG structure and its application in band-notched UWB filter

In this paper, a new way of obtaining a band rejection in a ultra wideband (UWB) filter using a uniplanar Electromagnetic bandgap (EBG) structure is reported. The EBG structure has a bandgap centered at 6.69 GHz which is almost 38% lower compared with the conventional uniplanar EBG of same dimensions. A one-dimensional EBG structure coupled with a microstrip line provides a narrow bandgap, which is used in obtaining a notch in the UWB filter. Single notch UWB filters with variations in the placement of EBG are fabricated producing a notch centered at 5.19 GHz (wireless local area network (WLAN)). A dual notch (5.16 and 8.24 GHz (satellite communication)) UWB filter is also fabricated with two different unit cell EBGs'. Switchable and tunable notch band UWB filters are proposed.

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.