<s>
Plane	B-Algorithm
wave	I-Algorithm
expansion	I-Algorithm
method	I-Algorithm
(	O
PWE	O
)	O
refers	O
to	O
a	O
computational	O
technique	O
in	O
electromagnetics	O
to	O
solve	O
the	O
Maxwell	O
's	O
equations	O
by	O
formulating	O
an	O
eigenvalue	O
problem	O
out	O
of	O
the	O
equation	O
.	O
</s>
<s>
We	O
can	O
use	O
the	O
following	O
code	O
in	O
MATLAB	B-Language
or	O
GNU	B-Language
Octave	I-Language
to	O
compute	O
the	O
same	O
band	O
structure	O
,	O
</s>
<s>
Large	O
size	O
problems	O
can	O
be	O
solved	O
using	O
iterative	O
techniques	O
like	O
Conjugate	B-Algorithm
gradient	I-Algorithm
method	I-Algorithm
.	O
</s>
<s>
The	O
PWEM	B-Algorithm
is	O
highly	O
efficient	O
for	O
calculating	O
modes	O
in	O
periodic	O
dielectric	O
structures	O
.	O
</s>
<s>
Alternatives	O
include	O
Order-N	O
spectral	O
method	O
,	O
and	O
methods	O
using	O
Finite-difference	B-Algorithm
time-domain	I-Algorithm
(	O
FDTD	B-Algorithm
)	O
which	O
are	O
simpler	O
,	O
and	O
model	O
transients	O
.	O
</s>
