Lumped Port Microstrip antenna set up

Hi folks,

i am completely new to COMSOL and i am struggling with a few basic things for my uni project. I followed the tutorial for the inset microstrip antenna provided. I must have done this ten times now and it works fine. I tried to transfer the same procedures over to my design, a circular polarised microstrip antenna but i am having a few problems. My end goal is to find the S parameters and impedance so i can design a quarter wave transformer to go on the end to match the antenna. The design is really simple, i have attached it at the bottom if anyone wants to take a look.

Anyways the mesh seems to be an issue

I have one mesh covering the inner sphere (i think this is a gaussian surface or something to calculate electric fields but it doesn't say. The tutorial used a free tetrahedral mesh and creates a further 2 sizes. One for the microstrip line edges, or at least that's what the turorial seemed to do so i selected my edges too and one cover the ground, substrate and patch... i dont know if this is right because i aint got a clue where the ground is on the turoial one given as the patch is inside the substrate.....

anyways, i get a few errors,

Edge is much shorter than the specified minimum element size.
Face is (or has a narrow region that is) much smaller than the specified minimum element size.

Question 1
previously i never had to specify a minimum element, i thought it would just do this for me.... how do i choose an appropriate minimum element???


Question 2
on the tutorial for the lumped port domains, he chooses the microstrip line edge which is to be excited, i have done this but when i compute the study i receive the following message

error in automatic sequence lumped port .....

any ideas??

and thanks for your help.

Lee.