Problem with resonance in CST when simulating electric field on a bow tie antenna

Hi Guys,

I'm simulating Electric field on a bow tie antenna. I'm using a linearly polarized plane wave illumination and my aim is to observe the z-component of the E-field beneath the antenna. When i put a field probe to observe the resonances i see the first two resonance at 215 and 570 ghz. However when i look at the field at 570, it does not seem to be really in resonance. I'm also not being to able to monitor the field after 750 ghz. Even if i increase it by 50 ghz, the resonance curve takes a strange shape. Actually, i'm not being able to sure where to put the probe. First, i tried the center but it gave strange results.

I'm uploading my file. Do you think i'm doing something wrong during the resonance sweep? Or any idea what's the problem?

I'll appreciate very much if you could help me.

Thanks,