MMIC Design LecturesIII-3HO

III-3HOIII-3. Impedance Matching with Transmission Lines
(1) Transmission Lines for Planar Circuits-(1)
Microstrip Lines

- inhomogeneous structure (air above and dielectrics below microstrip line) Maxwell eqn and boundary condition > longitudinal component of E, H field of dominant mode > quasi-TEM mode (hybrid mode)

γ = ( R + jωL)(G + jωC ) = α + jβ ,
vp = 1 = LC 1 = c = c

β = ω LC =
, λg =

2π

λg
Ζ0 = R + j ωL 1 ≈ vp L = G + j ωC v pC

ε

rε r

εr

λ0 , εr

ICE651 MMIC Design

III-3-1

III-3. Impedance Matching with Transmission Lines
(1) Transmission Lines for Planar Circuits-(2)
Slotlines

- signal transmission by TE mode - implementable in the ground plane of microstrip line circuits for design flexibility and some new type of circuits (hybrid coupler) - confine the fields near the sl