The junction capacitance in resonant interband tunneling diodes is det
ermined using microwave impedance measurements from 40 MHz to 62 GHz a
nd network parameter extraction. The shape of the capacitance in the p
ositive differential resistance region is totally different from the r
esonant tunneling diode. The difference can be explained by the intrin
sic transport process of carriers in a resonant interband tunneling di
ode, what is manifested in the conductance characteristic of the devic
e.