Influence of technological errors of design parameters of a resonant-tunneling diode-based subharmonic radio frequency mixer of 10…11 GHz range operating on heterodyne’s second harmonic on its performance indices’ (intermediate frequency’s transmission losses, dynamic range’s top border by 1dB-compression, IP3 point’s position) distributions was studied. The following design parameters’ influence was researched: microstrip transmission lines’ linear dimensions, substrate’s thickness and relative permittivity, resonant-tunneling diode’s heterostructure layers’ thickness and chemical composition, mesa’s diameter and ohmic contacts’ resistivity. A mathematical model of resonant-tunneling diodes developed by authors was used to carry out the research, taking technological factors’ influence on the studied mixer’s performance indices into account. It is revealed that technological errors of a resonant-tunneling diode’s resonant-tunneling heterostructure’s layers’ thickness and chemical composition, combined with technological errors of spacer layers’ thickness, make dominant contribution in the technological variation of the studied mixer’s performance indices.