I have met a problem in antenna feed.a coaxial cable is used to feed the antenna from the bottom of substrate,but I don't know how to draw the waveport and also donot know how to draw the model of coaxial cable.in particular ,the coaxial cabel's characteristic resistance must be 50Ω
Please search for some tutorials on HFSS in this forum. There are a lot of examples to draw waveport.
You need to use some tool (like LineCalc of ADS or txline of AWR) to calculate the dimension of coaxial cable to get 50 ohm impedance. For an example, D_o = 4.15 mm, D_i = 1.8 mm and E_r = 1 gives you 50 ohm impedance @ 8 GHz (D refers to Diameter, i = inner conductor, o = outer conductor).
Take a look at the file how to draw waveport. I changed your model a little bit. However, it is better that you follow the example/tutorial of HFSS.
Ok, I think that your antenna can not work,
why, i ve just seen in the file of shameem for a bit, you have chose the perfect E for the GP, but you did not find out that you had to creat a "hole" in the GP, for what? for isolation of feeding probe with your masse, so try again pls,
dr- you can take a plan for GP, creat a hole at fding point ok!