Search

This paper presents a modified rectangular microstrip patch antenna (MRMPA) array conforming to the hemisphere for wide-angle beam scanning. Two different conformal antenna array designs are presented in this work. The first of these designs, a 13-element MRMPA array conformal to the surface of a circular arc, and the second one, a 9-element array conformal to the surface of a hemisphere, are designed and optimized. The geometrical approach of calculating the phase value is used to calculate the phase value of each antenna. The simulated results show that the 13-element conformal MRMPA array is achieving a beam scanning angle of ±84° with a gain of 13.89 dBi with low side lobe levels, and further, the gain of the array is enhanced by a dielectric superstrate that improved the gain by ∼2 dBi at all the scanning angles. Second, an MRMPA array conformal to a hemisphere with nine elements is designed with beam scanning ability from φ = 0°−360° and θ = ±30° with a gain of 15.69 dBi, and further, the gain is enhanced by ∼3 dBi with the dielectric superstrate. Full-wave simulations have proven both designs to be accurate and aligned with theoretical calculations. [ABSTRACT FROM AUTHOR]

Recently, electromagnetic metamaterials are of great interest to researchers because of their unusual electromagnetic properties. The proposed work presents a metamaterial as a superstrate for enhancing the performance parameters of a conventional patch antenna. The metamaterial unit cell is examined using classical waveguide theory to confirm its metamaterial properties such as permittivity and permeability at the resonant frequency. The proposed meta-structure comprises of a 5 × 5 array of circular-shaped split ring resonators backed with wire strips and placed above an inset-fed rectangular patch antenna that resonates at 9.96 GHz. The metamaterial superstrate improves the gain, impedance bandwidth, and radiation efficiency by 2.4 dBi, 770 MHz, and 18.4%, respectively and simultaneously reduces reflection coefficient by 5 dB. Several benefits such as compact size, simpler structure, low profile, and low cost have been obtained from this design. EM simulation of the proposed composite structure has been carried out with the help of the HFSS EM simulator and measurement has been done for validation. [ABSTRACT FROM AUTHOR]

The design and analysis of a four-port multi-input multi-output (MIMO) super wideband antenna (SWB) with a metamaterial superstrate are proposed. Initially, a single antenna is constructed with a hexagonal radiator loaded with dodecagon slots along with a slotted partial ground. An impedance bandwidth of 4.1–14.7 GHz is achieved by using symmetric coplanar waveguide feeding technique and three iterations of dodecagon slot-loaded radiating element. The design is extended to a 2 × 2 MIMO antenna with dimensions 50 × 50 × 1.6 mm3. The four symmetrical SWB antennas are placed orthogonally to each other at four corners of a square-shaped FR4 substrate. A metamaterial superstrate is used above the four-port antenna to increase the antenna's performance characteristics. A 7 × 7 array of rectangular metamaterial unit cells acts as a building block for the metamaterial superstrate to improve impedance matching, enhance isolation between the elements, and boost the antenna's gain. The metamaterial unit cells are made up of three rectangular rings that are put on top of a 1.6 mm thick FR4 substrate. With a mutual coupling of (>15 dB), the antenna achieved S11 < −10 dB for an impedance bandwidth of 11 GHz. The gain enhancement of up to 1.73 dB is obtained in C and X bands using metamaterial superstrate. The antenna characteristics mainly peak gain, return loss, bandwidth, and isolation are examined. The simulated results affirm a decent deal with experimental results. [ABSTRACT FROM AUTHOR]

In this paper, a high refractive index-based metamaterial Bi-convex lens superstrate for the gain enhancement of broadside radiating antennas like microstrip antennas is presented. Fundamentally, an effective HRI medium is created by the Single Ring Split Ring Resonator unit cells printed on an FR-4. By stacking the multiple layers of the superstrate, a virtual HRI-based equivalent Bi-convex lens is constructed to focus the incoming diverged beam from a patch antenna. A gain enhancement of 4.42 dB is achieved with the help of a 3-layer HRI-based Lens superstrate. The simulation and measurement results are also almost agreed on the same. [ABSTRACT FROM AUTHOR]

We present microstrip patch antenna loaded with multiple split ring resonator substrate and superstrate. We analyze how the loading of split ring resonator superstrate and substrate can improve the bandwidth compared to the simple microstrip patch antenna and microstrip patch antenna loaded with split ring resonator superstrate. Another important observation is made for multiple split ring resonator loading in superstrate and substrate of microstrip patch antenna. The design is compared for two, three, and four-ring split ring resonator loading. The designs are also compared for different gap spacing between the rings. All three designs are compared for small gap and large gap between the rings. The design results in the form of reflection coefficient and bandwidth is presented in this manuscript. The design results are also compared with previously published designs. [ABSTRACT FROM AUTHOR]

Left-handed material (LHM) is applied to reduce the radar cross section (RCS) of microstrip antenna when the incident wave is non-perpendicular to antenna. The LHM having the magnitude of its refractive index close to zero can be used to the total reflection phenomenon and focus the electromagnetic wave. Therefore, the method of RCS reduction with LHM superstrate is presented. Two kinds of the LHM structure are proposed and two application examples are present. The simulated and measured results show that 5–20 dB RCS reduction under the condition of oblique incidence is obtained when the LHM superstrate is used. The RCS reduction angle range can be changed by adjusting the size of the LHM superstrate. [ABSTRACT FROM AUTHOR]

In this article, we present two models to predict the quality factors for computing the impedance, bandwidth, and gain for a superstrate-loaded rectangular patch antenna. These models employ a set of CAD-oriented closed-form expressions based on conformal mapping, transmission line, cavity model, and single resonant parallelL-C-Rcircuit. These models are very simple and take less computational time. The accuracy of these models is verified against experimental results. This structure is also validated with the HFSS computation results. [ABSTRACT FROM AUTHOR]

We have introduced metamaterial superstrate in microstrip-based radiating structure to increase its bandwidth. Split ring resonators are added as metamaterial metallic inclusion in superstrate of the conventional design. This changes the basic structure of the material. Material properties such as permittivity and permeability changed due to change in the structure. The change in its material properties enhances the bandwidth of the antenna. The antenna is meandered to achieve better performance at the edges which in a way improve the radiation path of the patch. Here, the proposed antenna works on three bands in the range 3–8?GHz. Maximum 60% bandwidth is enhanced in the third band. The voltage standing wave ratio and return loss (S11) of the entire three bands are shown in the paper. The antenna works on 3.51, 4.86 and 7.8?GHz. Design results are obtained by high-frequency structure simulator which is used for simulating microwave passive components. [ABSTRACT FROM AUTHOR]

In this study, a subwavelength aperture antenna with multiple corrugations and a superstrate layer was investigated based on Fourier transform and mode matching, demonstrating a rigorous and fast convergent series solution. The aperture antenna with a corrugated conducting flange and a dielectric superstrate was fabricated in the X-band frequency range to demonstrate the validity of the derived series solution. The measured reflection coefficient and radiation pattern of the proposed antenna are also presented and compared to the computational results to assess the effect of the dielectric superstrate. A maximum gain enhancement of 5.19 dB was achieved by employing the superstrate. [ABSTRACT FROM AUTHOR]

Currently, substrate thin film solar cells with Cu(In,Ga)Se2(CIS) absorbers yield conversion efficiencies of up 20.4%, the highest published efficiency of CIS superstrate thin film solar cells is 12.8%. It is the maximum efficiency when composition is as follow; Cu, In and Se was 1, 1 and 2. The maximum efficiency of CIS superstrate thin film solar cell is smaller than that of CIS substrate thin film solar cell, but manufacturing cost of CIS superstrate is lower than that of CIS substrate since the reduce of the manufacturing process. In addition, CIS absorber layer is fabricated through binary phases to reduce the process temperature and processing price. In this study, CIS superstrate thin film solar cell was fabricated to reduce the device manufacturing cost and CIS absorber layer was deposited by the binary phases. By using substrate (Sodalime Glass,SLG), window layer(i-ZnO, Al:ZnO)were deposited on n-type transparent electrode layer in the upper part. CIS absorber was respectively deposited by In2Se3 and CuSe in a binary phases by using MBE(Molecular Beam Epitaxy). The deposited sample went through heat process, and then electrode was created to fabricate the device. In order to identify the structural and electrical characteristics depending on CuSe deposition time, CIS absorber and CIS solar cell device, analysis was conducted by using XRD (X-ray Diffractometer, Bulk, PANalytical), FE-SEM (Field Emission Scanning Electron Microscope, S-4800, HITACHI), ICP(Inductively Coupled Plasma, ICPS-8100, Shimadzu),SIMS (Secondary Ion Mass Spectrometry, IMS 6F, CAMECA) and solar-simulator(AM1.5g, 100 mW/cm2). [ABSTRACT FROM PUBLISHER]

The maximum efficiency of Cu(Inx,Ga1-x)Se2(CIS) superstrate thin film solar cell is smaller than that of CIS substrate thin film solar cell, but its device fabrication price is lower because the number of thin-film process is fewer. In addition, CIS absorber layer is fabricated through binary process to reduce the process temperature and processing price. In this study, CIS superstrate thin film solar cell was fabricated to reduce the device fabrication cost and CIS absorber layer was deposited by the binary process. By using Sodalime Glass (SLG), Al:ZnO and ITO were deposited on n-type transparent electrode layer in the upper part. CIS absorber was individually deposited by InSe(In2Se3) and CuSe in a binary type by using Molecular Beam Epitaxy (MBE). The deposited sample went through heat process, and then electrode was created to fabricate the device. In order to identify the structural and electrical characteristics of the various transparent electrodes, CIS absorber and CIS solar cell device, analysis was conducted by using X-ray Diffractometer(XRD, Bulk, PANalytical), Field Emission Scanning Electron Microscope (FE-SEM, S-4800, HITACHI), Inductively Coupled Plasma (ICP, ICPS-8100, Shimadzu), Secondary Ion Mass Spectrometry (SIMS, IMS 6F, CAMECA) and solar-simulator (AM1.5 g, 100 mW/cm2). [ABSTRACT FROM PUBLISHER]

Radiation from a superstrate loaded cylindrical-rectangular microstrip patch antenna with an air gap between the ground and the substrate is analysed using the full-wave approach and the electric surface current model. Results are presented in the form of normalised radiation patterns and directivity patterns for various thicknesses of the air gap, to show the effects of the air gap on the radiation from the antenna. Both axial and azimuthal current elements are considered. [ABSTRACT FROM AUTHOR]