All possible second-order four-impedance two-stage Colpitts oscillators

The authors report all the possible four-impedance settings that yield a valid second-order two-stage Colpitts oscillator. These settings are obtained following an exhaustive search conducted on two possible structures of the oscillator modelled through two-port network transmission parameters. Only valid second-order cases with a maximum of three reactive elements are reported. Experimental and Spice verification of a selected example using both MOS and BJT transistors is given.