In this paper, high frequency limitations of injection locked power amplifiers (ILPAs) are studied. A new phase alignment technique is proposed to minimize the loss of both injecting and oscillating devices at tens of gigahertz. Analytical results are verified by spice simulations. The theory is carried to design an ILPA at 60 GHz. Comparison is performed with the Class-E PA, and the cross-coupled ILPA. Post-layout simulation results show that the power added efficiency (PAE) of the phase aligned ILPA is the highest of the three, reaching 40% while it is 32% and 24% for the cross-coupled ILPA and the Class-E PA respectively, using the standard 65 nm CMOS node.