High-quality (high-Q ) on-chip microresonators have been shown to be a promising platform for Kerr soliton frequency comb generation. Si3N4 microresonators composed of multimode waveguides can achieve high-Q factors and anomalous dispersion, which are necessary for soliton generation. To further reduce the threshold power for generating a singlesoliton microcomb, a novel racetrack Si3N4 microresonator with Euler bends has been reported that achieves loaded Q factors greater than 5×106. Compared with conventional circular bends,the sudden change in the bending radius at the waveguide connection is significantly suppressed,which in turn suppresses mode interaction and reduces propagation loss. With this novel microresonator, single-soliton frequency combs with a repetition rate in the microwave Ka band and a bandwidth exceeding 20nm (corresponding to a pulse duration of 129fs) are generated using only a 47mW pump laser (33mW estimated on-chip pump power) under the auxiliary laser heating method