Cassegrain Antenna Design Errors

I'm trying to run the attached code for a Cassegrain antenna, changing the frequency from 18 GHz to the GPS frequencies 1575.42 MHz and 1227.6 MHz. I changed the frequencies and the following errors came up: "Error in em.MeshGeometry/updateMesh, Error in em.MeshGeometry/getMesh, and Error in em.EmStructures/analyze". Can you help resolve the errors?

Rp=0.3175;
fp=0.2536;
Rsub=0.033;
fhyp=0.1416;
ant=cassegrain('Radius',[Rp Rsub],'FocalLength',[fp fhyp]);
show(ant);

Exciter=design(hornConical,17.7e9);
Exciter.FeedWidth=3.4e-3;
Exciter.Tilt=270;
Exciter.TiltAxis=[0 1 0]; 
show(Exciter);

●

ant=reflectorParabolic('Radius',0.3175);
ant.Exciter=design(hornConical,17.7e9);
ant.Exciter.Tilt=90;
figure;
pattern(ant,18e9);

ant=cassegrain;
s=sparameters(ant,linspace(18e9,18.8e9,25));

Error using matlab.internal.capability.Capability.require (line 94)
Support for Java user interfaces is required, which is not available on this platform.

Error in waitbar (line 48)
Capability.require(Capability.Swing);

Error in em.EmStructures/analyze

Error in em.PortAnalysis/impedance (line 198)
status = analyze(obj,freq);

Error in em.SharedPortAnalysis/protectedsparameters (line 134)
Z = impedance(obj,freq,UseParallel=options.UseParallel);

Error in em.PortAnalysis/sparameters (line 48)
S = protectedsparameters(obj,freq,z0,UseParallel=options.UseParallel);

figure;rfplot(s);


figure;
impedance(ant,linspace(18e9,18.8e9,25));

current(ant,18e9,'scale','log10');

Exciter=design(horn,16.2e9);
Exciter.Tilt=270;
Exciter.TiltAxis=[0 1 0]; 
ant.Exciter=Exciter;
show(ant);

figure;
pattern(ant,18e9);

[Walter Roberson]

I ran the above code in R2025a (pre-release). It took a while, but it ran without error.

[James Manns]

Yes, it runs fine at 18 GHz. How do I change it to 1575.42 MHz and 1227.6 MHz? That's when I get the errors.

[Walter Roberson]

I have not worked with Antenna toolbox before, so I am not sure what changes you are looking for.

When I try

 pattern(ant, 1575.42e6)
 pattern(ant, 1227.6e6)

or

 s=sparameters(ant,linspace(1200e6, 1600e6,25));

or

 impedance(ant,linspace(1200e6, 1600e6,25))

everything looks plausible when I test in R2023a.

[James Manns]

That's it. It runs fine now. Thanks.

Answer 1

[Sharath Maadam]

Script seems to be running fine without any errors in 24b version.