| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 104 === Two divide-by-2 cross-coupled Injection Locked Frequency Dividers (ILFD) have
been put under experimental stress conditions. Comparison of stress effects is made between
thick-gate cross-coupled transistors and thin-gate cross-coupled transistors. Degradations due
to hot-carrier stress have been found. The cross-coupled MOSFETs have different effect on
power consumption than the injection MOSFET, increasing it while the latter is decreasing it.
Increase in output power, decrease in locking range and optimal gate bias shifting to a higher
level are observed as contribution from injection MOSFET’s degradation. The experiment
successfully isolate the effect of stress-degraded injection MOSFET.
An LC-tank divide-by-2 Quadrature ILFD (QILFD) using the capacitive cross-coupled
oscillator has been studied. The quadrature operation is obtained by ring transformer coupling.
The highest FOM achieved is 3.78 at VDD = 0.85V, VR = 0.8V, with locking range from 9.1 to
12.8 GHz. The lowest power consumption is 7.39mW at VDD = 0.7V, VR = 0.8V, with FOM of
3.44 and locking range from 9.6 to 12.4 GHz. The widest locking range is achieved at VDD =
1V, VR = 1.1V, with FOM of 1.81 and locking range from 8.6 to 13.7GHz. The power
consumption can be controlled by changing the gate bias (VR) of switching transistors. The
QILFD can operate at VDD < VR conditions. Higher Figure of Merit (FoM) still require VDD >
VR condition.
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