How to define capacitor in HFSS 9.0

define capactor

I try to define capacitors for circuit and then tyr to add port this capacitance.
However I define a box and from Lumped element properties I defined capitance for the box. But when I start to simulation give error. I write below:
proje_yap1 (C:/Ansoft/HFSS9/)
HFSSModel1
[info] Simulation completed with execution error on server: Local Machine. (11:04 Ara 28, 2004)
[error] Port refinement, process abc3d : There are no boundaries to define "WavePort1_capacitor" correctly. This may be due to incorrect material definitions for those objects that make up the port surface. Please verify the material assignments and properties. (11:04 Ara 28, 2004) [warning] Warning - Boundary 'LumpRLC1_capacitance', Boundary 'Rad1' : Boundaries overlap. (11:04 Ara 28, 2004)
[warning] Warning - Boundary 'LumpRLC1_resistance', Boundary 'Rad1' : Boundaries overlap. (11:04 Ara 28, 2004)
[warning] Warning - Boundary 'LumpRLC1_resistance', Boundary 'Rad1' : Boundaries overlap. (11:04 Ara 28, 2004)
[warning] Warning - Boundary 'LumpRLC1_capacitance', Boundary 'Rad1' : Boundaries overlap. (11:04 Ara 28, 2004)

I will be greateful, anyone helps me.
Thanks.

define capacitor

Try to use (CPW) waveguide port. Verify parameters of your model.
See the presentation file attached. Its from ansoft.