Multiple input multiple output dielectric resonator antenna for long term evolution applications

Abstract

Wireless communications have been part of human life where people can communicate worldwide with very high speed through the use of new technology known as Long Term Evolution (LTE). LTE is an evolution in wireless communication system which is capable of providing high data rates and high speed transmission. In addition, a multiple input multiple output (MIMO) technology enables wireless communication systems to achieve high data rates and high quality of services by placing multiple antennas at transmitter and receiver. Multiple antennas should be designed to have good isolation even when closely spaced. A ceramic material with several attractive feature swhich is called a dielectric resonator (DR) is used as a radiation element in this thesis.This thesis presents three designs of dielectric resonator antenna (DRA) that operate at 2.6GHz for LTE applications. Firstly, a coplanar waveguide (CPW) rectangular DRA(RDRA) without and with metallic strip has been designed. The measured impedance bandwidths (BWs) for CPW RDRA without and with metallic strip for S11 < -6 dB are 45%and 66%, respectively. The gains obtained for CPW RDRA without and with a metallic strip are 2.92 dBi and 3.12 dBi, respectively. Secondly, an MIMO F-shaped DRA is designed. The measured impedance BWs for S11 < -6 dB are 36% for port 1 and 31% for port 2, respectively with S21 = 33 dB. The antenna provides gain of 1.99 dBi for port 1 and1.85 dBi for port 2. Lastly, an MIMO RDRA is designed. Two orthogonal modes of the MIMO RDRA are excited by using two different feed mechanisms which is CPW and coaxial probe. The measured impedance BWs for S11 < -6 dB are 47% for port 1 and 25%for port 2, respectively with S21 = 33 dB. The antenna provides gain of 4.97 dBi for port 1and 4.51 dBi for port 2. Then, the third design was extended by using higher relative permittivity value of DR in order to reduce the antenna size. It can be seen, both second and third designs produced correlation coefficient well below 0.5 with nearly 10 dB diversity gain. A reasonable agreement between the simulated and measured results has been achieved.