what should be angle of phi and theta to plot gain vs freq of this omnidirectional pt

hi all
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what should be angle of phi and theta to plot gain vs freq of this omnidirectional pttern in hfss
../imgqa/eboard/Antenna/rf-fh0ocpl4tnk.png
regards
kartik

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radiation pattern of this antenna is attached

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../imgqa/eboard/Antenna/rf-huryuqrrv3d.png

In the plot, you see two curves: phi=0° and phi=90°
Each curve is from theta=-180° to theta=180° (one full turn around the axis)

I want to plot rectangular plot in terms of gain vs freq and do not know how to plot that
at what angle of theta and phi