Abstract <p>This paper provides a comprehensive simulation study of MgZnO/ZnO High Electron Mobility Transistors (HEMTs), emphasizing their DC, RF, and noise characteristics for high-frequency and low noise applications. Simulations were performed utilizing the Silvaco TCAD platform for gate lengths of 0.25 and 0.5 µm to assess the impact of device geometry on performance. The DC characteristics, encompassing drain current in relation to drain-source voltage (<i>I</i>_D–<i>V</i>_DS), drain current about gate-source voltage (<i>I</i>_D–<i>V</i>_GS), and transconductance (<i>g</i>_m) behaviour, validate improved carrier transport and current drive capability. The RF analysis indicated a cut-off frequency (<i>f</i>_T) of 95 GHz and a maximum oscillation frequency (<i>f</i>_MAX) of 235&#xa0;GHz for the device with gate length of 0.25 µm, reflecting improvements of approximately 25 and 30%, respectively, over conventional ZnO and GaN-based HEMTs. Additionally, the minimum noise figure (<i>N</i>_Fmin) was decreased to 1.66 dB at 11 GHz, representing a 20% reduction compared to similar GaN devices. The quantitative enhancements confirm the MgZnO/ZnO heterostructure as a viable option for RF, microwave, and low-noise amplifier applications within the Ku, K, and Ka frequency bands, characterized by superior scalability, elevated electron mobility, and minimal power dissipation.</p>