RF Electronics Chapter 11: Circuit Manufacture Page 381
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
7 line Lange couplers with 5 µm tracks and spacing. Implementing the design on silicon
or gallium arsenide, allows active devices to be incorporated in the same MMIC.
Figure 11.15 [50] shows a MMIC amplifier produced using a GaAs PHEMT 0.15 µm
process. The amplifier is a 2 stage power amplifier where the input is split into 4 using 2
cascaded Wilkinson hybrids. Each signal is then amplified and 2 outputs are combined
into one and impedance matching is applied. The resulting signal is then split into 4 and
amplified. The outputs from the top 4 and the bottom 4 amplifiers are then combined
using Wilkinson hybrids to produce a 27 dBm (0.5W) output at 35 GHz. The chip size is
2.45 x 2.95 mm.
Figure 11.15. GaAs MMIC amplifier chip [50].
Figure 11.16 [51] shows a mm-wave power amplifier, made using 60 nm GaN on Si
HEMT technology. The input is split into two, using a Lange coupler. Those signals are
then amplified using 3 amplifier stages, their outputs are combined using another Lange
coupler, to produce an output power of more than 26.5 dBm, from 88 to 93 GHz. The
inter-stage matching networks can clearly be seen on figure 11.16. The size of the chip is
2.4 x 2.0 mm.
Since the 26-28 GHz band is used for 5G mobile phone communications and the 75-110
GHz frequency band is used for automotive cruise control radar, concealed weapon
detection and satellite communications, the mm-wave frequency band is becoming very
important for consumer applications.
The design techniques described in this book can thus be used to produce layouts for RF
PCBs as well as MMICs.
RF Electronics: Design and Simulation
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