A method of generating a signal representing with an ion energy analyzer for use in determining an ion energy distribution of a plasma. The ion energy analyzer, used for determining an ion energy distribution of a plasma, includes a first grid and a second grid that is spaced away from and electrically isolated from the first grid. The first grid forms a first surface of the ion energy analyzer and is positioned to be exposed to the plasma. The first grid includes a first plurality of openings, which are dimensioned to be less than a Debye length for the plasma. A voltage source and an ion current meter are operably coupled to the second grid, the latter of which is configured to measure an ion flux onto the ion collector and to transmit a signal that represents the measured ion flux. The method includes selectively and variably biasing the second grid relative to the first grid.