CMOS quadrature VCO using the injection MOSFET coupling

Abstract

In this example, the width of guiding ridge is equal to 200 nm. Moreover, the height of the silicon, silica and gold layers are 340, 50, and 50 nm, respectively. Therefore, the total height of the guiding ridge is h ¼ 440 nm. The fundamental mode in this case is TM-like, meaning that it is the E y component that is dominant. Figure 5(b)-(d) depicts the absolute value of the electric field components corresponding to the fundamental TM mode for an operating wavelength of 1.55 lm, as obtained by the solution of the 2D eigenvalue problem. The distribution of the dominant electric field component (E y ) reveals that most of the mode energy is guided inside the 200 Â 50 nm 2 silica layer, verifying that the confinement is indeed subwavelength. Again, the hybrid nature of the mode in question is evident by noting the relative amplitude of the transverse electric-field components and the fact that both axial field components (electric and magnetic) are nonzero.Turning to the 3D-guided-wave problem, plots (b)-(d) in Figure 6 depict the absolute value of the electric-field components along the waveguide, for both the proposed and default ABCs. The length of the waveguide segment considered is L ¼ 1.2 lm, corresponding to $1.61 k g for the mode in question (k g ¼ 0.747 lm at the free-space wavelength of 1.55 lm). In addition, in Figure 6(a) the overlap integral along the waveguide is depicted. As with the previous example, the proposed ABC permits the correct excitation and absorption of the mode in question, and thus a purely guided wave is propagating in the structure. On the other hand, when the default ABCs are used, a standing wave pattern is formed, owing to reflections from the two ports. One might also notice that when the standard ABCs are used, both transverse electric field components are excited with higher amplitudes than dictated by the solution of the 2D eigenvalue problem. This is because at the cross-sectional points associated with their peak value, g 0 /n eff is smaller than both Z TM w and Z TE w . On the contrary, in the previous example of a silicon wire waveguide, E x is excited with a lower amplitude, as g 0 /n eff > Z TE w at the respective cross-sectional point. Finally, let us note that the slight negative slope evident in the field component and overlap integral plots is because of propagation (resistive) losses. Specifically, for the waveguide dimensions considered, the propagation length, that is, the distance at which the optical intensity has dropped by a factor of e À1 , is $23 lm. CONCLUSION

Complementary current reuse quadrature voltage‐controlled oscillators

“…Fig. 12b shows a complementary cross-coupled CR QVCO [22], which consists of two cross-coupled CR VCOs used as first-harmonic injection-locked oscillators (ILOs) [17]. The bodies of (M p3 , M p4 ) are controlled by a tuning voltage V tune and the common gate of (M p3 , M p4 ) is used as an injection port.…”