
166 Gallium Nitride (GaN): Physics, Devices, and Technology
of the n
th
transistors in the TWA required for the TML in Figure 5.12 actually can
be expressed as
∑
×
⋅=
1
=
1
(Ohm mm)
0,
0,
î=1
,
Y
ZR
W
n
nP
n
Qi
(5.16)
The resulting impedances Z
0,n
of the TMLs are very high for the rst transistors
to be realized, as the last transistor n has to yield a minimum value of the nal load
impedance Z
n
,0. With typical values for the resistor R
P
, it is more efcient to choose
bigger transistors for the rst n. Various NDPAs have thus been realized in GaN as
the TWA principle in a non-uniform way [103,118].
A design with a non-uniform distribution is depicted in Figure ...