Antennas and beam-steering arrays for polarization diversity and full-duplex applications
Abstract
This thesis presents new designs for polarization diverse dielectric resonator antennas
(DRAs) as well as antennas that can offer efficient full-duplex (FD) functionality. Basically, this research effort has been completed to meet the demands of modern tracking
systems as well as in-band full-duplex communication systems. For these applications
antenna polarization control, compatibility, co-location, and isolation are the important
parameters to support these high-performance systems.
The first part of the thesis covers the challenges of modern radio frequency (RF)
environments where the proposed polarization reconfigurable antennas are introduced.
At first, a multi-port DRA is outlined as a possible candidate for the global positioning
system (GPS) and the Global Navigation Satellite System (GNSS). To further advance
this original design, and in an effort to reduce the size whilst maintaining polarization
control, an integrated circuit was also proposed and tested.
Advancing from the research work of phase polarization control using DRAs, the
second part of the thesis studies other new antennas which are suitable for FD communications. Those antennas offer high isolation which makes the signal recoverable for those
FD systems. To advance the state-of-the-art, an H-shaped slot antenna arrangement with
parasitic patches and dual-differential feeding was proposed. The antenna architecture
was investigated with both external and integrated feed systems and both prototypes offer
high isolation levels. The single-element was further integrated into a 1×4 antenna array
which was shown to offer similar isolation levels and with the capability to beam steer.
Further research included high isolation antennas for operation in the 5G mm-wave
band. In particular, a new FD pattern reconfigurable antenna was proposed which can
be used in dual-polarized radars and other FD systems. Depending on the input phase
excitation, the beam pattern control can be established with sum or difference patterns
or both. Also, the antenna concept was further extended into a novel FD antenna array.
This array has a similar common and/or differential feeding which can provide sum or
difference patterns in the far-field. Also, an external Butler matrix was used to investigate
the beam-steering capabilities of the array. These antenna systems also have applications
for dual-polarized radars, retro-directive arrays, and other beam-tracking scenarios which
require high inter-port isolation.