Advanced Electromagnetics (E-Journal)
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A Planar UWB Antenna with Dual Band Rejection Capability Using Double Rotated ESRRs
No full textIn this paper, CPW-Fed ultra wideband (UWB) planar monopole antenna (PMA) loaded by double elliptical split ring resonators (ESRRs) for double band-notch characteristics is introduced and examined. Two different ESRRs with different dimensions are printed in the antenna backside to notch two different frequencies. The ESRRs are also rotated and the corresponding return loss effect is examined. Different notch frequencies can be obtained by varying the ESRRs, dimensions. Two single SRRs are used to notch two frequencies instead of using dual SRR pairs. Two notch frequencies at 5.2 GHz and 6.9 GHz has been obtained to notch WLAN and C-band wireless applications, respectively. A directive radiation pattern in E-plane and omnidirectional radiation patterns in the H-plane could be observed. Also the gain is suppressed in the notch frequencies. The group delay is nearly stable in the UWB frequency range, except at the notch frequencies, which is distorted sharply. So, the proposed antenna is a good candidate for the modern UWB systems. Finite element method FEM and finite integration technique FIT are used to simulate the proposed structures through the usage of Ansys HFSS and CST MWS. Very good agreement between both results has been obtained
A Triple-band Suspended Microstrip Antenna with Symmetrical USlots for WLAN/WiMax Applications
No full textIn this study, a triple-band suspended microstrip antenna with symmetrical U-slots is proposed for modern wireless communication systems. The antenna is specifically designed to acquire application in WLAN and WiMAX communication. Symmetrical U-slots in the radiator patch increase the number of resonances and improve the gain response. An appropriate air height was maintained between the ground plane and the radiator patch layer for improving bandwidth operation. The impedance characteristics of the antenna are enhanced using probe feeding techniques. The proposed compact antenna is designed on a single dielectric substrate of (30×25×1.56) mm3 . Parametric analysis of the proposed structure has been realized using IE3D software. This prototype exhibits maximum impedance bandwidth of 750 MHz and gain response of 7.28 dBi. The performance of the structure at three resonating bands i.e., at 3.3 GHz, 3.78 GHz and 5.3 GHz facilitate it to be applicable for WLAN/WiMAX systems
Jamming Efficacy of Variable Altitude GPS Jammer against Airborne GPS Receiver, Theoretical Study and Parametric Simulation
No full textSatellite-based navigation systems, as one of the key infrastructure of development in manned and unmanned guidance systems, is vulnerable against the simplest form of attack in Electronic Warfare environments. This led us to investigate the described vulnerability of an airborne GPS receiver against jammers which are located at various altitude above the targeted point. To do that and to avoid encountering with unavailability of classified information about military-class missiles, some simplification was done and the problem was investigated in “Worst Case” conditions. Finally, the flight profile and radiation pattern of the antenna of the GPS receiver were theoretically modeled. Considering some assumptions, the other parameters were derived from them. At the end, a simulation software was developed and some results were extracted. The data was represented figuratively and the dependency of efficacy of jamming operation to the jammer’s altitude and flight profile of the missile were discussed
Multi-port Pattern diversity antenna for K and Ka-band application
No full textA compact coplanar waveguide (CPW) fed reconfigurable antenna with pattern diversity using multi-port excitation is designed. The basic antenna consists of a circular patch of radius 2.5mm which is fed by four ports independently. By exciting the patch with each individual port, the direction of the radiation pattern changes by 900. With the use of CPW feed technique, a very wide impedance bandwidth of around 12GHz (21.65 – 33.87 GHz) covering the K-band and Ka-band is achieved. The proposed antenna can be used for different satellite communication applications like earth exploration, radio navigation and location, mobile satellite communications which comes under K-band and Ka-band. The measured return loss and pattern characteristic results are in good agreement with simulated ones
CSRR based patch antenna for Wi-Fi and WiMAX Applications
No full textIn this paper, a novel compact microstrip patch antenna is proposed for Wi- Fi and WiMAX bands. To achieve miniaturization the dimensions of the square radiating patch are chosen with reference to the high frequency band (3.3 GHz). The dual band is achieved by loading a Complementary Split Ring Resonator (CSRR) into the radiating patch. The left handed nature of the CSRR is the cause for low frequency band (2.4 GHz). To improve the return loss bandwidth and axial ratio bandwidth at upper band the fractal concept is introduced along the edges of the square patch. Thus a low volume dual band antenna is simulated using HFSS. A comparison with measured data is also presented. The fabricated antenna is found to be occupying 25% less volume (with reference to 2.4 GHz) than existing antennas which is mainly due to the blending of the two recent concepts ‘metamaterials and fractals’
Gain Enhancement of Monopole Antenna using AMC Surface
No full textA CPW rectangular-ring antenna over an Artificial Magnetic Conductor (AMC) is presented in this work. The AMC is a designed as a dual-band structure having an array of unit cells and operates at 2.45GHz and 5.20 GHz. A CPW antenna uses this dual-band AMC structures as a back-plane. Performance comparison is carried out with and without incorporation of AMC. The simulated and measured results show that the combination of the AMC reflector and the antenna provide directional properties at both frequency bands. It has been found that the antenna gain increases by about 5 dB
Broadband Koch Fractal Boundary Printed Slot Antenna for ISM Band Applications
No full textA new broadband radiating slot antenna with fractal shape is modeled, fabricated and experimentally studied. The presented slot antenna is examined for first three iterations. Optimization of iteration factor (IF) and iteration angle (IA) have been done for each iteration order (IO) to enhance impedance bandwidth significantly. All the antennas are fed with a simple microstrip line. Bandwidth achieved with Antenna 1 (IO=1, IF=0.35 and IA=600) is 1550 MHz which is five times more than that of the square slot antenna. The performance of the proposed fractal slots is also compared with the rotated slot antenna. The experimental data validates the reported analysis with a close agreement
Miniaturized Wideband Microstrip Antenna for Recent Wireless Applications
No full textIn this paper, a pentagon slot inside fractal circular patch microstrip resonator to design compact antenna over partial ground plane is introduced using 3rd iteration of adopted fractal geometry. This antenna is modeled on FR4 substrate with a size of (20 x 18) mm2, thickness of 1.5mm, permittivity of 4.3 and loss tangent of 0.02. The used type of feeding is microstrip line feed. It is designed to operate at wide frequency range of (4.5-9.3) GHz at resonant frequencies of 5.7GHz and 7.9GHz with impedance bandwidth of 4.8 GHz. Both lengths of ground plane Lg and width of feed line Wf are optimized in order to acquire optimum bandwidth. The simulated return loss values are -33 and -41 dB at two resonant frequencies of 5.7 and 7.9 GHz with gain of 3.2 dB. The simulated results offered noteworthy compatibility with measured results. Also, the proposed wideband microstrip antenna has substantial compactness that can be integrated within numerous wireless devices and systems
Crossover Frequency and Transmission-Line Matrix Formalism of Electromagnetic Shielding Properties of Laminated Conductive Sheets
No full textThis paper proposes an approach to calculate the crossover frequency of each layer in the multilayered shield and subsequently that of structure constructed by n layers. This important frequency provides a useful approximation for field penetration in a conductor. It is used in a wide variety of calculations. It is in this context that a simplification of the transmission-line matrix formalism for laminated conductive sheets is done using this frequency. Two ranges of frequency are considered: lower and higher than the crossover frequency. Simples formulas and easy to use of the reflection loss, the internal reflection, the absorption loss and the electromagnetic shielding effectiveness of laminated shield are obtained. Analysis is carried out for the study of two shields: i) single shield of carbon nanotube polymer composites (CNTs), ii) multilayered shield constructed with Nickel–carbon nanotube polymer composites–Aluminum (Ni–CNTs–Al)
Gain Enhancement of Horn Antenna Using Meta Surface Lens
No full textThree dimensional meta surface lens is proposed to improve the gain and beam shaping of horn antenna. Hence an array of SRR as a meta surface lens has been designed, fabricated and investigated. This meta surface lens can be used to convert the spherical wave to plane wave for a wide range of frequency. It is proved by permeability and permittivity of meta surface. In this work the operating bandwidth of the proposed antenna is in the range of 9GHz to 11GHz for satellite application. The radiation pattern of E and H plane is sharpened in this work. The antenna 3dB beam width, and front to back ratio were 9.2, 28dB at 10GHz. The radiation characteristics of horn antenna with meta surface have been studied numerically and confirmed experimentally, showing an average gain improvement of ~3dB with respect to horn antenna without meta surface lens