Investigation of Performance of Different Kinds of Dual Band Patch Antennas for Mobile Phones
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Date
2007-03
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Addis Ababa University
Abstract
Mobile communications handsets with internal antennas become more popular every
day. These integrated antennas must be designed to fit into a small volume, with an
arbitrary shape. Indeed, the design of modern handsets is mostly fashion-oriented, and
the antennas must be adapted to these requisites, without detriment to their matching
or radiating performance [12]. The present study focuses on how a change in some of
the antenna geometric parameters, such as its height, may affect its actual
performance.
Dual band antennas are defined as:” Antennas that are useful in situations where the
antenna is required to operate in two distinct frequencies which may be too far apart for a
single antenna to perform efficiently at both frequencies. [8] In this thesis work different
dual band patch antennas for mobile phones are designed, simulated (using the EMPIRE
software) and the performance of which is compared based on the standard performance
measures.
The antenna put into consideration is said to be dual band if it operates on any two of the
bands: GSM, DCS, PCS, IMT2000 and Bluetooth bands. A total of 10 patch antenna
types: 5 from multiresonator and 5 from reactively loaded patch antennas are considered.
Of these the pins loaded patch antenna and a patch loaded with adjustable air gap have
better performance as they are closer to the regulatory performance measurement
standards compared to the rest. For pins loaded patch antenna the BW is 4.94% around
GSM1800 ( f MHz c = 1800 ), 3.04% around IMT ( f MHz c = 2170 ) and 4.08% around
Bluetooth ( f MHz c = 2450 ). For the patch loaded with adjustable air gap the BW is 10%
around GSM900 ( f MHz c = 900 ) and 2.33% around GSM1800 (DCS) ( f MHz c = 1800 ).
In both cases the BW is measured for S 9dB 11
£ − which is the regulatory standard for
measuring impedance bandwidth. As these two antenna structures are closer to the
regulatory standards of antenna performance measurement, they are suitable for dual
band mobile communication handsets except that in the former case the shorting pins
complicate the fabrication process.
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Keywords
Mobile Phones