This article proposes a new approach for the analysis and design of negativeresistance oscillators using computer-aided engineering tools. The method presented does not require any special probe and makes the oscillator design similar to the methodology applied to amplifiers. It speeds up convergence and avoids uncertainties in the solution. The negativeresistance oscillator is split into two parts: an active-amplifying part and a resonator part. A chain is constructed by linking both parts and repeating them several times, which is known as the repeated circuit simulation procedure. This method allows the separation of the signal flowing between them. Small-signal AC-sweep and harmonic-balance techniques, both available in several commercial software packages, are applied. This method is theoretically justified and shows convergence with less iteration. Furthermore, it is more robust than standard harmonic-balance probes in the case of multiple frequencies of oscillation. It has been demonstrated in the design of a quasi-MMIC VCO. This VCO has an external resonator circuit (coaxial resonator and varactor) and a MMIC negative-resistance circuit, which was manufactured using ED02AH p-HEMT technology (OMMIC).