We propose an approach for forming the dense bunches in turbulent electron beams with characteristics that promote the growth of the amplitude of the higher harmonics in the output spectrum. A design of microwave generator is also considered. The formation of translaminar electron layer by choosing the optimal voltages to the control electrode and an electron beam inhibition by the electrostatic field of the collector is used in the considered design of the generator. The above-mentioned factors create the necessary conditions for the formation of dense bunches of space charge of the electron beam. We have determined such control parameters as the spread of the electrons in the longitudinal velocities and the amount of additional inhibition of the electron beam by the electrostatic field of the collector, affecting the performance of electron bunches, and providing the growth of the number and the amplitude of the higher harmonic components in the spectrum of the output radiation. The previously obtained numerically simulated results are in qualitative agreement with the experimental data.