This paper proposes a switching load technique to improve the mismatch at outputs of the transformer-based single pole double throw (SPDT) switch, thus improving the insertion loss (IL) performance. A switch is introduced as the load of the primary inductor of the conventional transformer-based SPDT switch to improve the IL performance in transmission and receiving operation modes. A transformer-based SPDT switch is implemented with the switching load technique in TSMC 40[Formula: see text]nm CMOS technology. The transformer which has a symmetrical shape is implemented with the thick metal for low IL propose. The simulated results show that the proposed SPDT switch achieves a minimum insertion loss of 1.64[Formula: see text]dB and the IL is better than 2.2[Formula: see text]dB across the range from 24 to 35[Formula: see text]GHz. The proposed SPDT switch occupies a core area of [Formula: see text]m2 and the return losses are better than [Formula: see text][Formula: see text]dB at 24–35[Formula: see text]GHz.