Wideband Dual-Circular-Polarization Antennas for Millimetre-Wave Wireless Communications.
Abstract
Millimetre-wave (mmWave) wireless communications has attracted great interest in
recent years as a promising technology that can provide high data rate beyond 5G. Circular
Polarization (CP) radiation is preferable to Linear Polarization (LP) in mmWave
wireless communications, owing to the reliability of the wireless link it provides to suppress
multi-path fading and polarization misalignment. Apart from the link robustness,
high link capacity is also desirable by introducing technologies such as Polarization Division
Multiplexing (PDM) or In-Band Full-Duplex (IBFD). Therefore, this research aims
to design dual-circular-polarization (dual-CP) antennas with wide bandwidth and high
port isolation to enable PDM or IBFD for mmWave wireless communications thereby
achieving twofold spectral e ciency. The research work has been conducted in the following
four parts.
Firstly, a dual-CP horn antenna based on a stepped septum polarizer is designed in
the W-band. By optimising the horn pro le, a wide bandwidth with good isolation is
achieved in simulation and veri ed in experiment.
Secondly, to further push the limits of the dual-CP antenna based on the stepped septum
polarizer, a grooved-wall septum polarizer is proposed for the rst time with a 2-step
design method to realize a dual-CP antenna with wider operating bandwidth and higher
port isolation.
Thirdly, in order to ease the fabrication di culty and further improve the antenna performance,
a novel grooved-wall CP horn antenna is designed in simulation and veri ed
in experiment in the W-band. The dual CP performance can be generated when used
with an Orthomode Transducer (OMT), instead of a septum.
Finally, this septum-free approach has been generalised to design a multi-section groovedi
wall CP horn antenna with a low re
ection coe cient over a wide bandwidth in the
W-band. This horn antenna is demonstrated to be capable of achieving dual-CP with
high isolation over a wide bandwidth when used together with an OMT.
Authors
Shu., Chao.Collections
- Theses [4121]