Antenna plays an important role in any part of the communication system. It has to be designed very cautiously to provide improved system performance to meet the developments in wireless technologies with various design constraints such as small size, low cost, high data, low power consumption and wideband capabilities. Several efforts have been made by various investigators around the globe to amalgamate benefits of fractal structures with electromagnetic concepts and applications to reduce the size of the antenna without obstructing the performance of the antennas. This paper proposes a novel compact octagonal shaped broadband fractal antenna. The proposed antenna was designed on an inexpensive FR4-epoxy substrate and simulated using the High Frequency Structure Simulator. The antenna resonates in dual bands in 3.8 and 1 GHz with lowest return loss of − 32.80 dB and gain of 10.22 dB while maintaining the VSWR in the 2:1 level. Attempts have been made to reduce the size and improve the bandwidth using fractal concept and truncation of ground plane. The fabricated antenna was verified experimentally and the results are agreeing with the simulations. The point of attraction of this antenna is the use of single patch for broadband coverage with easy fabrication.

This paper proposes a novel crown shaped fractal antenna design suitable for 4G wireless applications. One of the promising approaches in miniaturizing the antenna size is to use the fractal geometries. Several efforts have been made by various investigators around the globe to amalgamate benefits of fractal structures with electromagnetic concepts and applications. This paper outlines a new approach in designing broadband monopole 2.1 GHz fractal antenna. The design starts with square patch antenna and goes up to third iteration for obtaining better performance and impedance matching. The proposed antenna was designed and simulated using the HFSS EM simulator. Performance analysis of the antenna was done with characteristics such as return loss, VSWR, efficiency and radiation pattern found to be good at 2.1 GHz. Wireless application demands miniaturization in system as well as antenna size with better performance, hence attempts have been made to reduce the size and improve the gain, efficiency and bandwidth of the proposed antenna.

This paper represents a brief description about design of rectangular microstrip patch antenna and its parameter effects in size, efficiency and compactness and parametric analysis in terms of return loss, bandwidth, directivity and gain by using same and different dielectric substrate materials with same and different thickness of rectangular microstrip patch antenna. The important parameters of patch such as L, W, ε r and h has its own impact in antenna characteristics. This parametrical impact is studied and verified. As thickness of dielectric substrate increases, the gain & directivity of rectangular microstrip patch antenna decreases and bandwidth increases. As ε r increases, the size of the antenna decreases but when height of dielectric substrate increase antenna size also increases. There will be always a compromise between miniaturization and other antenna characteristics. This antenna is designed for microstrip feed line technique and with center frequency (f 0 ) at 4 GHz. The parametric analysis is obtained by comparing the simulated results of rectangular microstrip patch antenna for different cases. The proposed antenna is simulated using HFSS tool at resonance frequency of 4 GHz.

This paper presents the design of a coplanar waveguide (CPW) fed ultra wide-band circular monopole antenna for UWB communication with frequency notch characteristics. The electromagnetic coupling of the SRR with the CPW yields the frequency notch. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated. The performance and characteristics of the antenna are investigated by FEM technique and better results were obtained in order to understand its operation.

It is proposed that a new image enhancement scheme using wavelet transform, smooth and sharp approximation of a piecewise non linear filter technique after converting the RGB (Red, Green, and Blue) values of each pixel of the original image to HSV (Hue, Saturation, and Value). Wavelet transform is then applied to the luminance value of V component, it decomposes the input image into the four subbands by using Discrete Wavelet Transform (DWT).The low frequency sub-band is smoothened and the high frequency sub-bands are sharpened by using non linear piecewise filter. The inverse DWT to the smoothened low frequency sub-band and sharpened high frequency sub-bands. 1-level decomposition is used in the proposed system. The saturation components are enhanced by histogram equalization; the H components are not changed, if it changes in the H components could cause the color balance between the HSV components. The enhanced S and V combined with H are converted back to RGB values. The method has effectively achieved a successful enhancement of color images. The experimental result vividly displays the proposed algorithm is efficient enough to remove the noise resulting good enhancement.