Error Unrecognized property 'L' for class 'patchMicrostrip'.

When i run my code Matlab give me this Error, i dont know why

freq = 10e9; 
lamda = physconst('LightSpeed')/freq; 
ant_len = 0.5*lamda;
ant_width = 0.1*lamda; 
ant_height = 0.01*lamda; 
ant_imp = 50; 

ant = design(patchMicrostrip, freq); 
ant.L = ant_len; 

Unrecognized property 'L' for class 'patchMicrostrip'.

ant.W = ant_width; 
ant.H = ant_height;
ant.Z = ant_imp; 

theta = linspace(-pi/2,pi/2,181); 
phi = 0; 
[PAT,theta] = pattern(ant,freq,theta,phi);

figure;
polarplot(theta,abs(PAT),'LineWidth',2);
title('Diagrama de Radiación de la Antena de Microbandas');

Answer 1

[Walter Roberson]

There is still an error in the below because I could not figure out what property Z might be intended to represent.

freq = 10e9; 
lamda = physconst('LightSpeed')/freq; 
ant_len = 0.5*lamda;
ant_width = 0.1*lamda; 
ant_height = 0.01*lamda; 
ant_imp = 50; 

ant = design(patchMicrostrip, freq); 
ant.Length = ant_len; 
ant.Width = ant_width; 
ant.Height = ant_height;

ant

ant = 
  patchMicrostrip with properties:

               Length: 0.0150
                Width: 0.0030
               Height: 2.9979e-04
            Substrate: [1×1 dielectric]
    GroundPlaneLength: 0.0300
     GroundPlaneWidth: 0.0300
    PatchCenterOffset: [0 0]
           FeedOffset: [0.0030 0]
            Conductor: [1×1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1×1 lumpedElement]

ant.Z = ant_imp; 

Unrecognized property 'Z' for class 'patchMicrostrip'.

theta = linspace(-pi/2,pi/2,181); 
phi = 0; 
[PAT,theta] = pattern(ant,freq,theta,phi);

figure;
polarplot(theta,abs(PAT),'LineWidth',2);
title('Diagrama de Radiación de la Antena de Microbandas');