We demonstrate and characterize the microwave frequency combs utilizing both the dynamical single-beam and dual-beam injection schemes numerically. The dynamical single-beam injection scheme is realized by optical pulse injection to the slave laser (SL) from a pulsed laser. When the SL subjected to only the optical pulse injection from the pulsed laser, microwave frequency combs are generated by the nonlinear dynamics of the frequency-locked states with different locking ratios. The amplitude variation of ±18 dB in a 30 GHz range is obtained by precisely varying the operational parameters, injection strength, repetition frequency, and detuning frequency. In this paper, we propose the dynamical dual-beam injection scheme to improve the amplitude variation of the microwave frequency comb generated. The dynamical dual-beam injection is realized by both optical pulse injection and optical cw injection to the semiconducor laser. By utilizing the hybrid scheme consists of double optical injections, the advantages of each individual dynamical system are added and enhanced. As the result, the amplitude variation of the microwave frequency comb of ±3.0 dB in a 30 GHz range is achieved when operating the cw and pulse injection to the slave laser in stable locking and frequency locked states, respectively. In addition, the bandwidth enhancement of over 25 GHz is also observed.