Design and Development of Compact Fractal Antennas for Multiband Wireless Applications

Abstract

Currently, researchers have given much importance for designing a compact, multiband, and low cost microstrip antenna to meet the miniaturization requirements of portable/handheld communication equipment. The commonly used antennas are microstrip, slot and coplanar waveguide antennas. Antennas capable of operating at dual band, multiband, cost effective, and good bandwidth are needed for upcoming wireless standards. The physical size, weight and multiband are the major issues in wireless application. This initiated antenna researchers, to develop an assortment of antennas to fulfill the requirements. The inherent feature of patch antenna is to resonate for single narrowband. An antenna competent of screening assortment of frequency bands is desirable for present wireless applications. Fractal geometry is a solution which can solve the needs of wireless applications. Fractal geometry is a concept in mathematics through which miniaturization, multiband characteristics, and bandwidth are achieved to complete a range of wireless applications with improved return loss. Therefore, miniaturization has become the most important objective of a Radio Frequency (RF) designer. It offers mobility and affordability in wireless/mobile devices. Wireless Local Area Network (WLAN), and Worldwide Interoperability for Microwave Access (WiMAX) are a few mounting wireless standards in the midst of wireless technologies. The technology supports high speed data rates, wide band applications with wide coverage area, and mobility in cell site. The contact of self-affine fractal antenna is proposed for improving the inherent narrow operating bandwidth of microstrip antenna. To lay bare, a standard for a better coverage area, and mobility, WLAN Multiple Input-Multiple- Output (MIMO) is chosen. These MIMO technologies can be integrated in WiMAX standard also. Simulation treatment for self-affine fractal geometry for WLAN MIMO antenna is well thought-out. In simulation, it is found that these antennas have dual band of operation, and rejects frequency bands at other spectrums. The contact of self-affine fractal antenna is proposed. While fractal geometry with single layer is presented through coaxial feed technique, cost and complexity involved in fabrication of the primitive antennas are eliminated in the proposed structure. In open literature, substrate chosen for realizing the structures of antennas is readily available and they are cost effective. The simulated selfaffine fractal cantor antenna has been fabricated on a FR4 substrate with thickness of 1.6 mm, relative dielectric constant = 4.4, tan = 0.02, and the optimized antenna size is 38.734 mm × 28.757 mm × 1.6 mm . The gain of antenna is 1.97 dBi with directional pattern. This dissertation addresses a few novel self-similar fractal antennas. These self-similar fractal antennas are compact. The fractal antennas resonate for single, dual, and multiband wireless applications. For future mobile communication systems, these fractal antennas unearth a position as it