Dual carrier modulation (DCM) is a well-known transmission scheme for achieving frequency diversity in wireless communications. On the other hand, channel aggregation (CA) can fully utilize the available discontinuous spectrums and obtain much higher throughput. In this letter, we propose an approach to apply DCM transmission for two channel aggregation in 60 GHz wireless local area network (WLAN) systems based on the single carrier mode defined in the 60 GHz WLAN standard. We also investigate different detection algorithms and propose an optimized solution for frequency diversity combining. Our simulation results show that the proposed DCM transmission approach with the optimized detection algorithm can obtain more than 1.5 dB gain comparing with non-DCM approaches in CA.