Research And Design On Multi-Band Antenna With Miniaturization And Broadband

In 21 century, informatization not only improves the quality of people’s daily life, but also greatly improves the innovation of the whole society. Information transmission has become a part of life and happens everytime and everywhere. As a means for radiating or receiving radio waves, antenna is irreplaceable in modern wireless communication. Thus, antenna technology has attracted much attention. Tepically, miniature antenna, wideband and multiband antenna is very popular because of the tendency of the development of modern wireless communication to miniaturization, intelligence and multifunction.Microstrip antenna is one of the most important manifestations of antenna and became very popular in the 1970s primarily for spaceborne applications (high-performance aircraft, spacecraft, satellites). Today they are used for government and commercial applications (cars, and even handheld mobile telephones, headsets). Because of its outstanding properties of low profile, low cost, easily fabricated, we chose to study microstrip antenna in this paper.Afterward, a compact coplanar waveguide (CPW)-fed printed monopole antenna comprising of two square rings radiating elements and a truncated CPW ground for WLAN/WiMAX application is proposed. With two radiating rings, three resonant frequencies and three operating bands are obtained. Two quarter-circles in the ground are cut to improve the performance of impedance matching, especially in higher frequency. The simulated results show that three distinct operating bandwidths with 10 dB return loss are about 300MHz (2.4-2.72GHz),1.1GHz (3.18-4.0GHz) and 1.6GHz (4.5-6.1GHz), covering all the 2.4/5.2/5.8GHz WLAN and2.5/3.5/5.5GHz WiMAX bands. Furthermore, the antenna has a simple planar structure and a small volume of only 31*21*1.6mm3.Good radiation characteristics and acceptance peak realized gains are obtained over the operating bands.Finally, a compact wideband antenna comprising of a L-shaped radiating element which has a modified inverted-F structure and a C-shaped parasitic radiating element on the ground is proposed. Three resonant frequencies and a very wide operating band are obtained. A prototype of the proposed antenna has been constructed and experimentally studied. The measured results show that the operating bandwidth with 10 dB return loss is about 2.9GHz (2.11-5.01GHz),81.46%, respectively, covering LTE2500(2.5-2.69 GHZ),2.4GHz WLAN and 2.5/3.5GHz WiMAX bands.Furthermore, the antenna has a simple planar structure and a small volume of only 30×30×1.6 mm3. Good radiation characteristics and acceptance peak realized gains are obtained over the operating bands.