Swapna Devi

Design of a wideband microstrip antenna and the use of artificial neural networks in parameter calculation

This paper deals with the design of a multi-slot hole-coupled microstrip antenna on a substrate of 2 mm thickness that gives multi-frequency (wideband) characteristics. The Method of Moments (MoM)-based IE3D software was used to simulate the results for return loss, VSWR, the Smith chart, and the radiation patterns. A tunnel-based artificial neural network (ANN) was also developed to calculate the radiation patterns of the antenna. The radiation patterns were measured experimentally at 10.5 GHz and 12 GHz. The experimental results were in good agreement with the simulated results from IE3D and those of the artificial neural network. A new method of using a genetic algorithm (GA) in an artificial neural network is also discussed. This new method was used to calculate the resonant frequency of a single-shorting-post microstrip antenna. The resonant frequency calculated using the genetic-algorithm-coupled artificial neural network was compared with the analytical and experimental results. The results obtained were in very good agreement with the experimental results.

Neighborhood Search-Driven Accelerated Biogeography-Based Optimization for Optimal Load Dispatch

Lack of exploration capability of biogeography-based optimization (BBO) leads to slow convergence. To address this limitation, this paper presents a memetic algorithm (MA), namely, aBBOmDE, which is a new version of BBO to solve both complex and noncomplex economic load dispatch (ELD) problems of thermal plant. In aBBOmDE, the performance of BBO is accelerated by using a modified mutation and clear duplicate operators. Then, modified DE (mDE) is embedded as a neighborhood search operator to improve their fitness after a predefined threshold. mDE is used with mutation operator DE/best/1/bin to explore the search near the best solution. The length of local search is set to achieve a balance between the search capability and the excess computational cost. In aBBOmDE, migration mechanism is kept same as that of BBO to maintain its exploitation ability. Modified operators are utilized to enhance the exploration ability while a neighborhood search operator, further, enhances the search capability of the algorithm. This combination significantly improves the convergence characteristics of the original algorithm. The effectiveness of the proposed algorithm has been verified on five different test systems with varying degree of complexity. The results have been compared with other existing techniques. The results indicate that the proposed approach can efficiently solve practical ELD problems.

Electrically Small Patch Antenna Loaded with Metamaterial

Abstract In this paper, the authors present a new planar metamaterial loaded electrically small microstrip patch antenna. The rectangular microstrip patch antenna is loaded by metamaterial using planar square spilt ring resonators (SRRs). The unloaded rectangular microstrip patch antenna resonates at 23 GHz, whereas after loading it by metamaterial, the same antenna resonates at 9.51 GHz. In loaded condition, the resonant frequency of rectangular microstrip patch antenna reduces due to magnetic coupling. The dimensions of the antenna structure are 0.161λ × 0.192λ. Using the Chu limit, the size of the antenna comes to ka = 0.775, thus, satisfies the condition of an electrically small antenna (ka < 1). The antenna exhibits an impedance bandwidth of 512 MHz at a resonant frequency of 9.51 GHz. The calculated radiation Q rad is 18.86 which is larger than Qchu minimum, that is Qchu, = 3.43. The gain and directivity of this antenna structure are 3.2 dBi and 7.8 dBi, respectively. The proposed antenna structure is simulated on a dielectric substrate with coaxial fed without incorporating any additional matching network.

A New Method for Color Image Quality Assessment

Humans have always seen the world in color. In the last three decades, there has been rapid and enormous transition from grayscale images to color ones. Well-known objective evaluation algorithms for measuring image quality include mean squared error (MSE), peak signal-to-noise ratio (PSNR), and human Visual System based one are structural similarity measures and edge based similarity measures. One of the common and major limitations of these objective measures is that they evaluate the quality of grayscale images only and don’t make use of image color information. Since, Color is a powerful descriptor that often simplifies the object identification and extraction from a scene so color information also could influence human beings’ judgments. So, in this paper new objective color image quality measure in spatial domain is proposed that overcomes the limitation of these existing methods significantly, is easy to calculate and applicable to various image processing applications. The proposed quality measure has been designed as a combination of four main factors: luminance similarity, structure correlation, edge similarity, and color similarity. This proposed index is mathematically defined and in it HVS model is explicitly employed. Experiments on various image distortion types indicate that this index performs significantly better than other traditional error summation methods and existing similarity measures.

A novel method of using artificial neural networks to calculate input impedance of circular microstrip antenna

A new method of using artificial neural networks(ANNS) for calculation of input impedance of rectangular microstrip patch antennas has been adopted in this paper. The results obtained using ANNs are compared with the experimental findings, theoretical values. The ANNs results are more in agreement with experimental findings.

Metamaterial Embedded Wearable Rectangular Microstrip Patch Antenna

This paper presents an indigenous low-cost metamaterial embedded wearable rectangular microstrip patch antenna using polyester substrate for IEEE 802.11a WLAN applications. The proposed antenna resonates at 5.10 GHz with a bandwidth and gain of 97 MHz and 4.92 dBi, respectively. The electrical size of this antenna is 0.254𝜆×0.5𝜆. The slots are cut in rectangular patch to reduce the bending effect. This leads to mismatch the impedance at WLAN frequency band; hence, a metamaterial square SRR is embedded inside the slot. A prototype antenna has been fabricated and tested, and the measured results are presented in this paper. The simulated and measured results of the proposed antenna are found to be in good agreement. The bending effect on the performance of this antenna is experimentally verified.

Bacterial Foraging Optimization Technique Cascaded with Adaptive Filter to Enhance Peak Signal to Noise Ratio from Single Image

Abstract This paper proposes a new approach to enhance peak signal to noise ratio of highly corrupted image affected by impulse noise. The proposed technique is implemented using an adaptive median Alter and the bacterial foraging optimization (BFO) technique. The adaptive median Alter is used to identify pixels affected by noise and replace them with median value to keep the information uncorrupted. The BFO technique minimizes errors between adaptive median filter output image and noisy image to maintain an error percentage of 0.0001. It has been observed that results of the proposed method are superior to conventional methods in terms of perceptual image quality as well as clarity and smoothness in edge regions of the resultant image. This technique can remove the salt-and-pepper noise of highly corrupted images with a noise as high as 90%.

Modified biogeography-based optimisation (MBBO)

Modified biogeography-based optimisation (MBBO) technique is modified version of BBO which is a bio-inspired and population-based optimisation technique. Biogeography is the study of distribution of species in nature. In this paper, BBO is modified by applying the concept of mutation as extended migration in phenomenon of mutation and prevention of similar habitats. Mutation as concept of extended migration is based on sharing of the information from best solution which controls the diversity among the population limited to the near feasible solution. These make the fine-tuning of the algorithm from one generation to next and converge fast. Fourteen standard benchmark functions are used to demonstrate the performance of MBBO. The results are compared with eight other population-based optimisation algorithms with discrete version of population. The experimental results are analysed using statistical two paired t-test. MBBO performance is also compared with other modified BBO algorithms. To show the capability of MBBO to solve the problems of continuous type, MBBO and other optimisation algorithms are applied as soft computing tool to calculate the resonant frequency of rectangular microstrip patch antennas of different dimensions having various substrate thicknesses.

Velocity Modulated Bacterial Foraging Optimization Technique (VMBFO)

In this paper, a Velocity Modulated Bacterial Foraging Optimization Technique is proposed. The Bacterial Foraging algorithm is hybridized with Particle Swarm Optimization technique to reduce the convergence time while maintaining high accuracy. The hybridized optimization technique is tested on various benchmark functions like Sphere, Rosenbrock, Generalized Rastrigin, Griewank and Ackley. In addition to these, the proposed algorithm is also tested to calculate the resonant frequency of Rectangular Microstrip Antenna. The results are compared with the existing algorithms and that of experimental results and are found to be in good agreement.

Parameter calculation of rectangular microstrip antenna using Biogeography-Based Optimization

Miniaturized microstrip antennas are of great interest in the recent time especially in wireless communication systems and biomedical applications. To enhance efficiency, avoid co-channel, adjacent channel interference and associated complications accurate determination of resonant frequency is an essential requirement. A method to calculate accurately the resonant frequency is of great importance especially on such antennas like microstrip patch antennas that have inherently narrow bandwidths. The feed point calculation is also difficult in this type of antenna. Biogeography-Based Optimization (BBO) is a new bio-inspired optimization and is yet to be applied in antenna and electromagnetic engineering. In this paper, the authors have used BBO for accurate determination of resonant frequency and feed point calculation of rectangular microstrip antenna (MSA). The results are in good agreement thus encouraging the use of BBO for antenna design.