Demands for high-speed multimedia data communications increasing telescopically, pushing wireless transmission data rate with 2Gbps or higher. In these highspeed data communication systems, the bit error rate (BER) characteristic is dependent on a phase noise performance of the VCO. To meet the above challenges, it is necessary for these systems to have high performance VCO with low phase noise, low cost, wide tuning range, and high DC-to-RF conversion efficiency. The tiny VCO developed using SWR (Slow Wave Resonator) and mode-coupling techniques support high DC-to-RF conversion efficiency and low phase noise in compact size and also easily amenable for integration in the IC (integrated circuit) form. The typical measured phase noise @ 10 kHz offset from the 12 GHz carrier is −110 dBc/ Hz with 5V, 30 mA DC bias using slow wave dynamics in multi-mode regimes.