Compact ultra- wide band multiple input multiple output antenna

Abstract

In recent era, the demand of Ultra-Wideband (UWB) is increasing in medical science, radar technology and Wireless Personal Area Network (WPAN) applications because of high data rate and channel capacity. Several antenna designs have been proposed to incorporate the high data rate and capacity, i.e., Multiple Input Multiple Output (MIMO) based antenna that provide the higher data rate and channel capacity. However, designing the compact antenna, while meeting the commercial requirement of UWB-MIMO system and other design constraint, is becoming more challenging for design engineers. One of the most promising solution is to use the planner microstrip antennas for achieving higher data rates, compact size, low profile, low cost, easy to fabricate, ultra-wide bandwidth and multiple antennas on a single structure but to achieve the higher data rate is still an open research problem. Therefore, this thesis provides a solution for higher data rate of printed microstrip antenna for UWB-MIMO communication by using the inherent property of multiple antennas on same structure. This proposed solution provides higher data rate of UWB system using multiple antenna elements on single board along with the miniaturization of UWB-MIMO antenna using an isolation technique. In this regard, a compact UWB-MIMO antenna, consists of two monopoles with separate transmission feed lines and an isolation structure on the back side, with a compact size of 24mm x 29mm is proposed. The staircase cutting, U-shape cutting and ground plan etching on the backside of transmission feed line are used to achieve ultra-wide bandwidth. The two U shape monopole antennas are placed at 5mm and a stripe line of width 2mm connected to ground is introduced to increase the isolation between elements. The isolation is further improved by creating a slot in the middle of ground plan. A novel UWB antenna of smallest size of 26mm x 30mm with high value of isolation greater than 25 dB is presented in this thesis.