Eddy Taillefer, 程俊, 大平孝
Implementation of Adaptive Controller for ESPAR Antenna and Experiments for Performance Verification
Abstract:Nowadays, wireless communication systems are rapidly progressing, bringing
more and more functionalities to users. Also the number of users is
constantly increasing, and communication systems have to face to more constraints
of bandwidth, data rates, and specifically in mobile wireless systems,
the power consumption and mobile terminals size. The objective of
researchers and engineers is to permanently reduce the cost and size of components
without decreasing the quality of signal transmission.
ACR-ATR has proposed a Wireless Ad-hoc Community Network (WACNet)
concept, in order to use in ad-hoc communities, which are formed with
an unspecified number of people temporally connected with a common purpose.
In this new concept, a new kind of antenna is proposed, the ESPAR
antenna, a reactively controlled directive array that enables full azimuth directivity.
This antenna has low cost, low power consumption and high power
level.
Optimisation of the ESPAR antenna reactance is still a hard task; even
though different ways have been tested, like Hamiltonian algorithm, CMA
algorithm or genetic algorithm. A technique for adaptively controlling the
load reactance's on the passive radiators, thus forming both beam arid nulls
is presented[?], for the first time, for the ESPAR antenna.
In this paper, the purpose is the sector beam forming of the ESPAR
antenna[?]． Our work was to find an algorithm for this purpose and made
experiments to conform this aim in practical use of the antenna. Actually
this purpose has been succefully reached.
After presenting the WACNet concept, the ESPAR antenna features will be
shown in details. Then an algorithm[?] for ESPAR antenna will be shwon,
also, the modifications we made on this algorithm in order to fit to our purpose
will be explained.
Finally, to show how ESPAR antenna can form beam, and trace the antenna
sector pattern, simulations and experiments of this new algorithm will be
presented.