MPhil thesis of Lo Chi Wa - Department of Electronic & Computer ...

IQQIFig. 85 Other alternative arrangement of inductors and the corresponding layoutSimulation resultsBased on simulation, different degrees of mismatches of the resonant tanks are tested.For simplicity, cases with different values of mismatches of varactors in LC tanks aresimulated. Simulation results show that there are about 3 times' improvement in bothamplitude and phase matching (Fig. 86). In both original and our proposed design, theoscillators will malfunction when the phase and gain mismatches are larger than 15%and 5 degrees, respectively. However, for our proposal, the tolerance to degree ofmismatch of the LC tank for stable single frequency oscillation and constant phasedifference is improved by about 3 times (Fig. 86b) because the phase and amplitudemismatches are less for same LC tank mismatch. Similar improvements in amplitudeand phase matchings are observed for mismatches from other sources, e.g. inductorvalues, quality factors, transistors' parameters.88