Equivalent circuit modelling of an l-shaped patch antennaby optimizing the lumped elements using differential evolution algorithm

L-shaped patch antenna (LPA) is formed by combining two monopole patch radiators. Proper modelling of a LPA using lumped elements is crucial in antenna design and analysis. In this study, a novel equivalent circuit (EC) modelingof an LPAusing differential evolution (DE) optimization algorithmis presented. Two parallel brancheseach represents the monopole patch radiator compose the EC topology.In eachbranch, a serial resistance and inductance pair stands for patch conductor, a parallel resistance and capacitancepair symbolizes the dielectric substrate. The expressions of theseeightlumpedelementsenclosing the antenna’s physical and electrical parameters accompanyingwith optimization variables are constituted considering the element definitions of microstrip transmission line(MTL). Return loss equationis derived through input impedance equation of the EC model. The variables are then optimallyfoundby fitting the calculated return loss to the simulated results by DEalgorithm. The proposed ECmodelisthenverified through resultsof simulated andmeasured LPA.Moreover, real and imaginary parts of theECinput impedanceare comparatively calculated. Theseresults showthat the proposed EC model gives almost the same results in terms of important antenna parameter

Small fringed cavity and slotted ground plane broadband microstrip antenna design

Mikroşerit antenler, kompakt yapıları ve baskı devre teknolojisi ile entegre ve kolay üretimi gibi avantajlarından dolayı son yıllarda haberleşme, savunma ve biyomedikal alanında yoğun bir şekilde kullanılmaktadır. Bu nedenle, bu uygulamalara yönelik küçük ve geniş bant anten tasarımı önem kazanmıştır. Bu çalışmada, 6.19 – 13.71 GHz rezonans frekans aralığında çalışan 14,8 x 16,8 mm2 boyutlarında bir mikroşerit anten Hyperlynx 3D EM benzetim yazılımı ile tasarlanmıştır. Antenin ışıyan elemanı saçaklı bir monopolden ve boşluklu bir toprak düzlemden oluşmaktadır. Antenin tasarımının önemli basamakları, rezonans bant genişliği bakımından incelenmiştir. Ayrıca önerilen antenin performansı, empedans bant genişliği, ışıma örüntüsü ve kazanç grafikleri üzerinden analiz edilmiştir. Bu sonuçlar, önerilen anten tasarımının küçük boyutlu ultra geniş bant uygulamalar için uygun olduğunu göstermektedir.Microstrip antennas have been used extensively in the field of communication, defense and biomedical in recent years due to their compact structure and advantages such as integrated and easy production with printed circuit technology. Therefore, the design of small and broadband antennas for these applications has gained importance. In this study, a 14,8 x 16,8 mm2 microstrip antenna operating in the resonant frequency range of 6.19 – 13.71 GHz was designed through Hyperlynx 3D EM simulation software. The radiating element of the antenna consists of a fringed monopole and a slotted ground plane. The important stages of the design of the antenna were examined in terms of the resonance bandwidth. Moreover, the proposed antenna was analyzed in view of some performance metrics such as the impedance bandwidth, radiation pattern and gain graphs. These results show that the proposed antenna design is suitable for small size ultra-wideband applications

Triangular aperture UWB antenna with dual band-notched characteristic for WLAN bands

A compact ultra-wideband (UWB) patch antenna with dual band-notched characteristic is designed for 2.4 GHz and 5 GHz WLAN bands. First an UWB antenna with size of 15.23×35.02 mm2 is designed, operating over 2.4-11.8 GHz. Then the bands are notched through a step-by-step optimization process. The UWB antenna is optimally achieved by loading triangular aperture between the patch and ground. The 2.4 GHz and 5 GHz bands are respectively notched by adding an inverted U-shaped slit on the patch and two C-shaped strips over the ground plane. The design procedure of the band-notched antenna is expressed by verifying through the return loss. Moreover, the notching mechanism and radiation performance of the antenna are studied with regard to surface current distribution, 2D and 3D radiation patterns and peak gain. The results demonstrate that the proposed antenna is applicable for UWB operation as well as has dual band-notched characteristic at the frequency range of 2.2-2.8 GHz and 4.5-6.8 GHz

G-shaped band-notched ultra-wideband MIMO antenna system for mobile terminals

WOS:000399751400019Low-profile band-notched G-shaped ultra-wideband (UWB) multiple input multiple output (MIMO) antenna design for mobile terminals has been presented. In this context, two UWB MIMO antenna systems have been designed: The first is with square elements and the second is with G-shaped elements. An MIMO antenna with two symmetrical square elements each of 8x8mm(2) operating between 2.2 and 13.3GHz was firstly designed for the UWB applications. Each square element was fed through a 50- microstrip transmission line (MTL). A thin strip line was designed at the end of MTL to provide impedance matching. Although the isolation level between the elements was satisfactory for efficient MIMO implementation, a T-shaped strip on the ground was employed to further improve the isolation for low frequency. The frequency range of 4.4-6.2GHz which is an important band of wireless local area network (WLAN) standard was then notched by forming a G-shaped structure on the square element. The performance of G-shaped antenna system was studied in terms of important antenna characteristics and MIMO parameters. The results demonstrate that the G-shaped MIMO antenna has nearly omnidirectional patterns, stable gain and good diversity performance besides having low-profile elements.BAP (Scientific Research Fund) department of Karamanoglu Mehmetbey University [12-M-15]This work is funded by BAP (Scientific Research Fund) department of Karamanoglu Mehmetbey University under grant no. 12-M-15. The author is thankful to Mustafa Tekbas for contributions to the experiments in Marmara Research Centre (MRC) of TUBITAK

Circularly polarized triangular patch antenna

Background: Circularly polarized (CP) antenna is an effective choice for wireless systems due to its insensitivity to the orientations of electromagnetic waves. Objective: A novel CP triangular patch antenna (CPTA) system is designed for ultra-wideband (UWB) applications. Methods: The CPTA, with a total size of 40.6 x 40.9 x 1.6 mm3, comprises a triangular patch posi-tioned on the aperture of a V-shaped ground plane and a feeding network that powers the two corners of the patch. The network consists of a T-shaped divider with a 50 Ohm microstrip transmission line (MTL) and two 100 Ohm MTLs, and two matching strips are inserted at the end of the MTLs. Results: The antenna system shows UWB performance for both impedance bandwidth (IM-BW) of 4-11 GHz and axial ratio bandwidth (AR-BW) of 3.5-8.0 GHz. A detailed review is further carried out to manifest the superiority of CPTA over the state-of-the-art technology. Conclusion: It thus provides compatible IM-BW and AR-BW for UWB operations due to its optimal compact design

Log-periodic dipole array-based MIMO antenna for the mobile handsets

WOS:000373739800005A novel design of multiple input-multiple output (MIMO) antenna based on the log-periodic dipole array (LPDA) for the mobile handsets is presented. The antenna operates in a wide frequency range of 1.86-3.84GHz compatible with GSM, LTE, WLAN, and WiMAX. The MIMO design consists of two symmetrical and orthogonal radiating elements and a neutralization line (NL). The radiating element comprises a LPDA having a series of printed dipoles connected together with a microstrip line. Triangular and rectangular cuts on ground plane are carried out in accordance with the LPDAs so as to increase the impedance bandwidth and isolation. The antenna elements are linked with the NL to further enhance the isolation between the radiating elements. The performance of the MIMO antenna is analyzed in terms of S-parameters, radiation pattern, gain, total efficiency, envelope correlation coefficient, mean effective gain, multiplexing efficiency; and then it is verified through the measurements. The results demonstrate that the proposed MIMO antenna has good characteristics of wideband, gain, radiation pattern, isolation, and diversity

A novel euler chaotic map for image encryption

A novel chaotic map based on Euler number namely Euler Map (EMAP) is suggested for image encryption algorithms (IEAs). The chaotic behavior of EMAP is appreciated with bifurcation analysis and Lyapunov Exponent (LE). The LE is the best due to the ultimate and most stable characteristic in case compared with the literature. A two-stage IEA, permutation and diffusion, is used to demonstrate the successful performance of EMAP, and this is how the success of EMAP is verified. The IEA with EMAP is examined in secure cryptanalyses and computational complexity. Some results are validated with the state of the arts. In the comparison, the suggested EMAP-based IEA stands out due to the diversity and complexity performance. It achieves a cropped image having minimum loss, a good operation time of 0.2297s and a low computational complexity. Therefore, the proposed EMAP can be applied to realistic systems

An optimized surrogate model using differential evolution algorithm for computing parameters of antennas

WOS:000692850500001In this study, a method based on surrogate model (SM) for computational analysis of antenna parameters such as the resonant frequency (RF) and bandwidth (BW) is presented. Moreover, it is attempted to optimize the SM using evolutionary optimization algorithms in order to further improve the accuracy of the SM. In the conventional computational approaches, the weighting vectors of the SM have been analytically determined. We have optimally achieved the weighting vectors of the SM through differential evolution (DE) and particle swarm optimization (PSO) algorithms. The capabilities of the algorithms are hereby compared with each other. The methodology is applied to the analysis of rectangular microstrip antenna (RMA), including a number of 33 measured RMAs with different geometrical and electrical parameters. From the total number of RMAs, 27 and 6 RMAs are, respectively, used in the construction and the test of the SM. Furthermore, the SM is verified through a comparison with the literature in terms of total absolute errors (TAEs). The results show that the SM with DE computes the most accurate RF and BW with the TAEs of 0.0099 GHz and 0.131%, respectively. The accuracy of the SM is further raised by 78%, thanks to the optimization of SM with DE. Therefore, a novel computational analysis method based on SM is implemented to computation of an antenna parameter with higher accuracy, and SM is successfully optimized by DE. The proposed method is able to easily implement to the stringent engineering problems based on simulated or measured data for computer-aided design (CAD)

Translational motion compensation for ısar ımages through a multicriteria decision using surrogate-based optimization

WOS:000538748700045Inverse synthetic aperture radar (ISAR) image is constructed using 2-D spatial distributions of the radar cross section of a target. ISAR data gathered from moving targets might include interphase error that causes a blurry effect in the ISAR image. In this article, an efficient motion compensation (MC) scheme depending on multicriteria decision using surrogate-based optimization (SbO) for minimizing the entropy and maximizing the sharpness of the images is proposed to remove the blur from the images. In order to provide a multicriteria decision, Pareto optimality is exploited to balance two criteria of the entropy and sharpness synchronously. A signal with an interphase error is input to the MC system for determining the global optimal motion parameters of the velocity and acceleration so as to focus on the ISAR image. The proposed scheme is implemented to four simulated ISAR scenarios reported elsewhere through two aircraft models for performance demonstration and comparison with artificial bee colony (ABC), differential evolution (DE), and particle swarm optimization (PSO) implemented in the literature. It is pointed out that the proposed scheme is more successful and efficient in view of the image focusing quality as well as the numerical results such as the motion parameters, the entropy and sharpness, and structural similarity (SSIM) index. The results also show that the SbO outperforms the other methods as the velocity and acceleration increase

Dual-element MIMO Inverted-F Antenna for Mobile Devices

In this study, a dual-element inverted multiple input multiple output (MIMO) F antenna (IFA) operating at 2.4 GHz band is designed by means of computational electromagnetic for WLAN wireless devices. The shape of IFA element resembles two superimposed E-shaped strips. IFA element with a small size of 10 × 13mm2 operates at the frequency range of 2.28-2.62 GHz. They are orthogonally placed at the corners of a 50 × 100mm2 main ground board for reducing the mutual coupling, i.e. correlation between the two elements. The radiation and isolation performance of MIMOIFA is examined in regards to the radiation patterns, envelope correlation coefficient (ECC) and peak gain. The proposed MIMO-IFA shows quasi-omni-directional pattern, under 0.05 ECC and about 2.7 dBi peak gain at 2.4 GHz. Therefore, it is a better and cheap candidate for 2.4 GHz industrial scientific medical (ISM) band including WLAN as well as wireless mobile devices