Antenna Design with Characteristic Mode Analysis for Internet of Things Applications
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The TV white space (TVWS) is one of the promising technologies to provide wide
coverage, energy effcient and cost effective Internet of Things (IoT) services. However,
its low operating frequency and wide bandwidth poses significant challenges to antenna
designs.
In this thesis, three antennas are developed using the characteristic mode analysis (CMA)
for IoT devices operating over the TVWS.
First, a very-low profile circular small antenna is transformed from a vertical monopole
antenna. The CMA is used to determine the mode to be excited and to design a specific feeding structure. After being printed on Rogers 5880 substrate, the final antenna
structure operates at 474 MHz with a V SWR < 2 bandwidth of 2.2 MHz. Its lateral
radius is just 5.2% of the wavelength of its resonant frequency.
Second, a compact U-shaped printed UWB monopole antenna is proposed to operate
over the entire UHF TV spectrum. This antenna measures 0:36 0 0:06 0 0:01 0
where 0 is the wavelength of its lowest operating frequency. Its V SWR < 2 bandwidth
is 87.5%, and the UWB behaviour is discussed by the CMA.
Third, a novel antenna design method is established on annular ring-shaped structures
with modal characteristics revealed by the CMA. Following the proposed method, another
UWB antenna is achieved by creating and exciting multiple modes with resonant
frequencies distributed across the UHF TV spectrum.
All antenna designs are verified thorough simulations and measurements. Furthermore,
antennas are also integrated into IoT devices and their system performance is measured
under different communication scenarios. The system measurements also verify the good
propagation property and the abundant spectrum resource of the TVWS.
Authors
Zhang, QianyunCollections
- Theses [4267]