Tim Brown’s
Undergraduate Project Ideas
My
specialist field where I am offering project suggestions is in the area of
antennas and radio propagation for wireless communications. I am also open to
suggestions that students have on a particular project that is related to
wireless communications and involves practical antenna construction and/or some
elements of RF electronics if the student can prove suitable competence in that
area.
Below is a
list of project suggestions that I have in the area of Multiple Input Multiple
Output (MIMO) Communications, which could involve measurements with CCSR’s wideband channel sounder as well as measuring
antennas in CCSR’s Anechoic Chamber. Also I will offer projects on
Ultra Wideband (UWB) channels The following project suggestions give a brief
summary of the concepts in both MIMO and UWB as well as a description of the
projects I want to carry out.
Students
interested in these projects or wishing to suggest other projects to me may
contact me by email on t.brownNOSPAM@surrey.ac.uk.
However, don’t forget to take out the “NOSPAM” as I just put that there to
prevent a harvest of spams coming in.
MIMO Communications
The
following diagram shows a brief idea of how MIMO communications operates. The
idea is that the base station (BS) and the mobile station (MS) have an array of
antenna elements, where a certain phase is applied to each element. These are
otherwise known as array weights. By applying the array weights in a certain
manner, it is possible to ascertain the directions of different incoming
signals at both ends, provided there are plenty of scatterers
as shown in the diagram. This can then divide a mobile radio channel into
sub-channels, for which there are then several “tubes” one can transmit data at
the same frequency. This will make better use of the limited frequency system
and thus increase the spectral efficiency as it is otherwise known. There is a
great market out there to design MIMO antennas and also characterise
the radio channel for MIMO, which our wideband
channel sounder has the capability to do at certain frequencies.
The following project suggestions are
available. All of them will require developing some understanding and familiarisation with MIMO to a modest level. Undergraduate
students at level 4 are introduced to the concept if they undertake appropriate
modules in mobile communications.
Design of a MIMO
Antenna using Switched Parasitics – The idea here is to create an
antenna that uses what are called parasitic elements (i.e. inactive antenna
elements next to an active one) that when connected to ground (shown below) or
disconnected they change the antenna pattern. The idea of this project would be
to design a practical antenna with these switched parasitics
and then see if it can generate the independent patterns.
Design of a meandered
IQHA at 2.4GHz – We
have a quadrifilar and meandered quadrifilar
shown in the pictures below. The meander allows the antenna to go smaller in
size though we need some software made up to design the meander PCB layout and
enable construction to work effectively. The work would require simulations,
construction (quite simple) and testing of the IQHA and even testing with our wideband
channel sounder if very successful.
Channel Sounder Post Processing Tool – Our wideband channel sounder
needs a useful post processing tool to instantly check the measured data after
measurement and ensure it is in order. A student with a good Matlab and Simulink background
will find this a good project if they want to find out a bit more about MIMO.
UWB Communications
The idea
behind UWB is that one can transmit a signal with a narrow pulse as shown below
that will result in a large bandwidth, so large that it is considered ultra
wide. The general rule is that any ultra wideband signal has a bandwidth wider
than 20% of the carrier frequency it is transmitting at. For example 4.5GHz has
bandwidth wider than 900MHz, which gives significant opportunity to transmit
large quantities of data. The US Federal Communications Commission (FCC) has
allowed UWB to transmit at a low power level of -41.3dBm between 3.1GHz and
10.6GHz. This brings challenges to design efficient antennas and find suitable
channel model environments that will enable UWB to be used at low power levels
in an office or home. Ultimately, the aim is that all electronic devices (e.g.
DVDs, computer monitors, laptops, data projectors, cameras etc.) will become
wireless and thus enable all devices to not need cables connecting them. Only a
power cable should be required.
Design of a UWB antenna on a hand held device – To design a UWB antenna with
appropriate specifications etc. and to test it placed onto a hand held device
and conduct suitable test and measurement.
Design of a dual mode compact UWB antenna – There are differing regulations in
the
Other Project Ideas
Design, building and calibration of some
standard antennas for ultra wideband in the anechoic chamber – To measure antennas in the
anechoic chamber, it is necessary to have some standard examples. The aim of
this project is to design and build some suitable antennas for ultra wideband
communications that can be used in the chamber as reference antennas properly
calibrated. There are different ways to undertake such calibrations and all of
these need to be tested and evaluated.
Diversity Antennas for Digital Broadcasting – One way to remove the impact of
multipath fading (where the signal varies rapidly in a mobile environment) is
to use diversity as shown in the diagram below. Two independent multipath
signals are combined so as to produce a reduced fading on the resultant
channel. That will likewise reduce the level of noise and increase the signal
to noise ratio. Therefore that represents the diversity gain. Few antennas have
been designed at 600MHz for digital broadcasting with compact design for this
and the project would aim to do that so that they could use diversity to
enhance the output.
Practical Diversity Gain of an Intelligent Quadrifilar Helix Antenna – The intelligent quadrifilar
helix antenna explained above in the MIMO section can also be used as a
diversity antenna. However, no tests have been carried out to see how this
works in practice, where the diversity gain would degrade the diversity gain as
explained above.
Generation of field animations in Ansoft HFSS – The aim would be to use Ansoft HFSS to
generate antenna patterns of typical antennas such as Hertzian
Dipoles and other demonstrations of Maxwell’s Equations and plane wave
propagation. Such animations would then be able to create a tutorial to be used
in the University. Examples of previous animations produced are for a second
year wave propagation lab here.
Tim Brown