ANALYSIS OF MULTIREFLECTOR ANTENNA CLUSTERS BY SPECTRAL METHODS V.E.Boria, M.Baquero, M.Ferrando Departamento de Comunicaciones, U.P.V. Camino de Vera s/n 46071, Valencia (SPAIN) Telephone: 34 6 3877307 Fax: 34 6 3877309 E-mail: Boriaedcom.upv.es ABSTRACT. This paper analyzes multireflector antennas making use of spectral domain techniques. The behaviour of the multireflector antenna is determined by means of a transference function that relates the plane wave spectrum of an incident signal on this antenna to the plane wave spectrum reflected by the structure. Multireflector antenna clusters that synthesize specific radiation patterns have also been undertaken. The paper allows us to generalize the identification of every reflecting object through a transference function that relates the incident spectrum to the reflected one. This will permit us to analyze reflection problems with multiple structures. INTRODUCTION. In order to obtain the transference function that characterizes the multireflector antenna, we have studied the reflected fields produced by parabolic and hiperbolic surfaces that integrate the multireflector structure. Reflector antennas have usually been analyzed by geometrical optics based on ray tracing. In this paper physical optics approximation has been used for characterizing reflector elements. It has been found the induced current distribution that an incident spectrum produces on the reflector surface. Using this current we get the reflected field and their plane wave spectrum. Once the behaviour of a multireflector antenna has been defined by an equivalent transference function we have shifted feeding sources from system focus and we have studied radiation patterns produced by several sources placed around the focus of a Cassegrain antenna. MULTIREFLECTOR TRANSFERENCE FUNCTION. The electromagnetic conduct of a multireflector antenna is defined by a transference function that relates the incident plane wave spectrum with the reflected one. Ew,(K..Kv,) Eu K,v R El\ \ Ex(K.Ay) lEN(.K)Ewr(.K o.\ (K,K,) - Input Spectrwm (plane wava) RI E.., (K..K,) - Output Spectrum (plane wave). H . ,al - Reflectou lYanaereuce Fwictslou Em (K5,K,) 1.a - Multireflctor rasfdereaca Function. Fig. I- Multireflector antenina. Fig. 2. - Multireflector transferenice function. 870