The present invention is a divide-by-three injection-locked frequency divider (ILFD) applying the linear operating characteristic of transistors to improve the locking range. The push-push structure of the ILFD generates a signal with twice the free-running frequency from the original free-running signal, and the injecting transistor mixes this with the input signal to generate a signal which the frequency is adjacent to the free-running. This signal can then result in injection locking within a specific frequency range, which is the locking range. Nonlinear mixing results in a complicated combination of harmonics while linear mixing avoids this flaw. Linear mixing facilitates injection locking and this fact in turn extends the locking range.