A technique is proposed for the design of multiband frequency selective sur
faces (FSSs) that is based on the use of fractal screen elements. The autho
rs demonstrate the design methodology by exploiting the self-similarity of
the crossbar fractal to implement a tri-band FSS. Another benefit of this d
esign approach, in addition to its multiband performance, is that the frequ
ency response of both the TE and TM modes are exactly the same, owing to th
e symmetry in the tree-like fractal structure of the screen elements. Diele
ctric loading effects have been considered for practical implementation of
designs with coverage exceeding two bands. Finally, it is noted that the lo
cations of the individual bands can be controlled by the scaling or similar
ity factor used in the construction of the fractal screen elements.