2 to 42 GHz flat gain monolithic HEMT distributed amplifiers

Ultrawide band monolithic HEMT (high-electron-mobility transistor) amplifiers have been designed and fabricated using MOVPE (metalorganic vapor-phase epitaxy) heterostructures. A cascode configuration has been used to reduce the coupling effects and therefore to improve the frequency bandwidth of the amplifier. A 6+or-1-dB gain was obtained from 2 to 42 GHz. In particular, a gain ripple better than +or-0.5 dB up to 26.5 GHz was measured directly on wafer. The I/O VSWRs (voltage standing wave ratios) are less than 2.5 over the entire bandwidth. The average noise figure of the amplifier is 4.2 at 12 GHz, rising to 5.2 at 18 GHz. The chip size is 2.3*0.9 mm/sup 2/. It is concluded that the results show that monolithic microwave integrated circuits using HEMTs are very promising for MM-wave applications.<<ETX>>