Dynamic tunability enhancement of reflectarray antenna using non-homogeneous dielectric materials
The conventional antenna systems require the mechanical movement of beam scanning antenna to meet the demands of emerging field of communications. To overcome the flaw of the mechanical movement an electronically tunable reflectarray antenna based on non-homogeneous properties of substrate mat...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2014
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/1586/1/24p%20MUHAMMAD%20HASHIM%20DAHRI.pdf http://eprints.uthm.edu.my/1586/2/MUHAMMAD%20HASHIM%20DAHRI%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/1586/3/MUHAMMAD%20HASHIM%20DAHRI%20WATERMARK.pdf |
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| Summary: | The conventional antenna systems require the mechanical movement of beam
scanning antenna to meet the demands of emerging field of communications. To
overcome the flaw of the mechanical movement an electronically tunable reflectarray
antenna based on non-homogeneous properties of substrate materials has been
introduced. This research study provides a thorough investigation on the tunability
performance of reflectarrays designed in X-band frequency range. The objective of
this work is to demonstrate the functionality of an active reflectarray antenna with
optimized loss performance and enhanced dynamic phase range. Different types of
reflectarray resonant elements such as rectangular, dipole and ring are discussed here
with different design configurations based on their ability of frequency tunability and
dynamic phase range. Commercially available computer models of CST Microwave
Studio and Ansoft HFSS have been used to investigate the phase agility
characteristics of reflectarray resonant elements printed above various non�homogeneous materials (0.17≤ ∆ε ≤0.45). The analytical approach has been used to
develop equations for progressive phase distribution and frequency tunability of
individual reflectarray element which is validated by CST simulations. The results
obtained from theoretical investigations have been further validated by experimental
implementations. An optimized configuration of non-homogeneous Liquid Crystal
(LC) material with 0.5 mm thickness below the resonant element has been designed
and tested by waveguide scattering parameter measurements. An external bias
voltage of 0V to 20V has been applied across the LC substrate of individual resonant
elements in order to obtain the electronic tunability. The three resonant elements
namely rectangular, dipole and ring offer a measured dynamic phase range of 95°,
153° and 197° respectively at 10 GHz using the proposed design configuration.
Moreover, the ring element attains a 107% higher dynamic tunability with a 56%
reduction in the reflective area as compared to rectangular element. |
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