XFDTD中的Wire和Port设置问题

周期性金属网格仿真，最好考虑线金属模型的FDTD，不知XFDTD有这个功能没有?

请教一下什么是线金属模型的FDTD，有参考资料吗?谢谢

关于wire模型，就是一种理想导体金属线，XFDTD可以设置不同粗细的wire——
出处：XFDTD 6.3 ReferenceManual.pdf
Thin Wires
Thin wire materials may be used in special situations where a wire with a radius much
smaller than the cell size is required.  In most cases, material #1 (PEC), will serve well
as a wire.  However, in cases where the wire radius is important to the calculation and is
less than approximately 1/5 the cell size, the thin wire material may be used to
accurately simulate the correct wire dimensions.  
Thin wire materials are subject to several restrictions due to the special modifications
they require on the field update equations. Thin wires may not meet at 90 degree angles
and they may not be located on adjacent cell edges. There must be a minimum of one
non-thin wire cell between any two adjacent thin wire cells.   Attaching thin wire materials
end-to-end is the desired method of using this material type.  
If a feed or port will be connected to a thin wire, the cell edge at the feed should also be
thin wire material, not free space.  For example, if a dipole antenna is simulated in thin
wire material, the feed "gap" should also be thin wire. Failing to use thin wire material in
the feed gap will lead to incorrect impedance and gain results. If you do add a feed or
port to thin wire materials, you may not specify inductance or capacitance values to that
port because these will interfere with the thin wire calculation.  However, resistor values
(series or parallel) may be used.
关于wire上的port设置，一定要直接在金属wire上的网格直接设置port

十分感谢楼上小编的指导。请教一下，Port的作用是什么，仿真电磁场的传播为什么要设置它?