S. Lucyszyn et Id. Robertson, OPTICALLY INDUCED MEASUREMENT ANOMALIES WITH VOLTAGE-TUNABLE ANALOG-CONTROL MMICS, IEEE transactions on microwave theory and techniques, 46(8), 1998, pp. 1105-1114
Monolithic microwave integrated circuits (MMIC's) may be measured unde
r relatively high-intensity lighting conditions, Later, when they are
packaged, any anomalies found in subsequent measurements could be attr
ibuted to unwanted parasitics or box modes associated with the packagi
ng. However, optical effects may not always be considered by radiofreq
uency (RF) and microwave engineers. For the first time, a qualitative
assessment is given for the effects of photonic absorption on three br
oad-band voltage-tunable analog-control circuits. Each circuit has a d
ifferent function, with each field-effect transistor (FET) operating i
n a different mode: a hot FET in a variable-gain amplifier, a cold FET
in an analog attenuator, and an FET varactor in an analog phase shift
er, All three circuit functions have been implemented using two differ
ent FET-based technologies. The first with ion-implanted 0.5-mu m GaAs
metal-semiconductor FET's (MESFET's) in circuits operating at either
3 or 10 GHz, The second employs epitaxially grown 0.25-mu m AlGaAs/InG
aAs pseudomorphic high electron-mobility transistors (HEMT's) in circu
its operating at 38 GHz, All the MMIC's were fabricated using commerci
al foundry processes and illuminated under conventional optical micros
cope lighting conditions. Prominent error peaks have been found at bia
s points unique to the three different circuit topologies, Large error
peaks are found with the MESFET-based circuits, while much smaller er
ror peaks are achieved with the corresponding pseudomorphic HEMT (pHEM
T) based circuits.