TL theory extended to 2D (or 3D) [9] [10]. Assuming that the electrical size of the unit
cell is small enough (p<<λg) and defining the series and shunt resonances respectively,
by, The phase constant  β  vary depending on whether the radicand is positive or
negative. It can be purely real or purely imaginary, respectively. When it is purely real,
a stop band occurs as shown in Fig.2(c) since  γ=α. This stop band is the unique
characteristic of the CRLH TL.
A particularly interesting situation occurs when the series and shunt resonances are
equal, as shown below:
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