This paper presents a design procedure for compact lumped-element 3-/4-/5-way Doherty power combiners suitable for mm-wave 5G transmitters. Among them, the 3-way Doherty power combiner is favored due to its low complexity, compact layout, and average drain efficiency at 12 dB power back off (PBO) when implemented using lossy lumped-elements. Based on the metal stack of a 40nm CMOS process, a 3-way Doherty power combiner can provide a simulated passive efficiency of more than 60% at 12 dB PBO and a 10% drain-efficiency bandwidth/3dB power bandwidth of 8/15 GHz at 30 GHz.