Hi arxlan,
I am attaching the HFSS design. As I mentioned earlier there are three ways to design FSS structures. Generally, if the FSS structure is symmetric, perf E/perf H option is easy and faster. It takes very less simulation time. So I simulated the structure with variable capacitor. And was able to reproduce Fig. 6.
In the paper, the author did not mention the length of the wire loop. So I used 3.9mm
If you still want the design with PML boundaries, let me know.
-sv