  Attaining high-fidelity two-qubit gates represents a pivotal quantum
operation for the realization of large-scale quantum computation and
simulation. In this study, we propose a microwave-control protocol for the
implementation of a two-qubit gate employing two transmon qubits coupled via a
fixed-frequency transmon coupler. This protocol entails applying two microwave
pulses exclusively to the coupler, thereby inducing interaction between the
fixed-frequency transmon qubits. This interaction facilitates the realization
of $\sqrt{i\text{SWAP}}$ gates. Additionally, we explore the implementation of
the gate scheme in two distinct qubit architectures. Demonstrating with
experimentally accessible parameters, we show that high-fidelity
$\sqrt{i\text{SWAP}}$ gates can be achieved
