www.gusucode.com > phased 案例源码 matlab代码程序 > phased/ULAGratingLobe1Example.m
%% Create Grating Lobe Diagram for ULA % Plot the grating lobe diagram for a 4-element uniform % linear array having element spacing less than one-half % wavelength. Grating lobes are plotted in u-v coordinates. %% % Assume the operating frequency of the array is 3 GHz and the % spacing between elements is 0.45 of the wavelength. All % elements are isotropic antenna elements. Steer the array in the direction % 45 degrees in azimuth and 0 degrees in elevation. % Copyright 2015 The MathWorks, Inc. c = physconst('LightSpeed'); f = 3e9; lambda = c/f; sIso = phased.IsotropicAntennaElement; sULA = phased.ULA('Element',sIso,'NumElements',4,... 'ElementSpacing',0.45*lambda); plotGratingLobeDiagram(sULA,f,[45;0],c); %% % The main lobe of the array is indicated by a filled black % circle. The grating lobes in the visible and nonvisible regions are % indicated by empty black circles. The % visible region is defined by the direction % cosine limits between [-1,1] and is marked by the two vertical % black lines. Because the array spacing is less than % one-half wavelength, there are no grating % lobes in the visible region of space. There are an infinite % number of grating lobes in the nonvisible regions, but only those % in the range [-3,3] are shown. %% % The grating-lobe free region, shown in green, is the range of % directions of the main lobe for which there are no grating % lobes in the visible region. In this case, it coincides with % the visible region. %% % The white area of the diagram indicates a region where no grating lobes are % possible.