Zhang, R. Su, X.M. Wang, X.W. Xu, Z. JACoW Publishing Geneva, Switzerland 2673-5482 978-3-95450-212-7 10.18429/JACoW-CYCLOTRONS2022-MOPO003 English 51-53 cyclotron ECR bunching injection operation Contribution to a conference proceedings 2023 2023-10 https://doi.org/10.18429/JACoW-CYCLOTRONS2022-MOPO003 https://jacow.org/cyclotrons2022/papers/mopo003.pdf To increase extracted beam intensity, the SFC cyclotron requires that the sawtooth wave buncher on its injection line provide the effective voltage up to 2.5kV and cover a wide frequency range of six times. We develope a multi-harmonic synthesis method by combining a broadband amplifier and impedance transformer, which provide a high-voltage single-gap buncher at limited space and cost. With this method, the maximum voltage of the new buncher exceeds 2.5kV and the beam intensity increases by a factor of 6.7.