In this paper, we report on simulations of an ESR (ESR) RF control line for semiconductor electron spin qubits.The simulation includes both the ESR line characteristics (geometry and configuration, stack and material properties) and the electromagnetic (EM) environment at the vicinity of the qubits such as gates and interconnect network.With the accurate assessment of the magnetic and elec. field distribution, we found that the EM environment of the qubits contributes significantly to the ESR line efficiency for spin control characterized by the magnetic over elec. field ratio generated at the qubit location.