This paper presents the design and simulation of a millimeter-wave Voltage-Controlled Oscillator (VCO) implemented in TSMC 65nm CMOS technology, operating at 28 GHz and targeting 5G Ka-band applications. The proposed circuit utilizes a complementary cross-coupled LC topology to maximize transconductance efficiency and minimize phase noise under strict power constraints. To ensure robust integration, the design includes output buffers employing inductive peaking to extend bandwidth and drive capability. Simulation results demonstrate a phase noise of –104.36 dBc/Hz at 1 MHz offset. The VCO core dissipates a power of only 2.1 mW from a 1.5V supply with a fast startup time of approximately 2.2 ns at an oscillation frequency of 28 GHz. By employing a common-source amplifier as a buffer stage, the output power is 5.6 dBm at 28 GHz. The achieved Figure of Merit (FoM) of -190 dBc/Hz validates the proposed design as a high-performance, energy-efficient solution for next-generation millimeter-wave frequency synthesizers. Keywords: VCO, 5G, Ka-band, LC oscillator, phase noise, CMOS, millimeter-wave