Integration of MIMO antenna with a fully 180^o differential hybrid coupler

Abstract:

This thesis work proposes the integration of MIMO antenna (i.e., two bowtie dipole antennas) with a fully differential 180^o hybrid coupler in the frequency range of 0.7-3 GHz which falls in the Ultra High Frequency (UHF) band as per the spectrum allocated by International Telecommunication Union (ITU). The applications in this band are Long Term Evolution (LTE), Global System for Mobile Communication (GSM), Global Positioning System (GPS), Digital Communication System, Personal Communication System, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Network (WLAN) and Global star satellite phone downlink and uplink.

This thesis introduces a new technique of integrating two bowtie dipole antennas with a fully differential 180^o hybrid coupler. The first part is design of bowtie dipole antenna in the desired frequency range of 0.7-3 GHz simulated using Advanced Design System (ADS) 2009 from Agilent Technologies Inc. In the design of bowtie dipole antenna started with a stepwise design with simple dipole antenna followed by parametric study. After literature study on different articles of wideband dipole antennas finally a bowtie dipole antenna was designed which covers the required bandwidth.

The second part is to design a differential 180^o hybrid coupler in the frequency range of 0.7-3 GHz simulated using ADS. Before implementing the actual differential 180^o hybrid coupler started with a design of fundamental single ended 90^o coupler followed by single ended 180^o coupler and by analyzing the results of both finally differential 180^o hybrid coupler was designed and observed the simulated results.

The last part of the thesis work is to integrate MIMO antenna with a fully differential 180^o hybrid coupler and to compare the results of isolation between antennas with and without coupler. To see in which degree the isolation can be improved by adding an 180^o hybrid coupler to the antennas.