Development of a Bipolar Radio-frequency Power Supply for Structures of Lossless Ion Manipulations

Structures for lossless ion manipulations (SLIM) is a new structure to realize the lossless transmission of gas phase ions by using the combination of electrostatic fields, radio frequency electric fields and ion driving electric fields under special background gas. Its potential applications in material transport and separation are numerous. In order to take full advantages of lossless ion manipulation structures in terms of cost and volume, a low-cost, high-frequency, bipolar radio frequency (RF) power supply with low complexity and compact design was developed in this study. The power supply employed an isolation module to provide electrical isolation between the control and power circuits. In addition, the output stage used a half-bridge circuit with GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) as the core devices. Given the capacitive load characteristics of SLIM, the filter characteristics of a resistor-inductor-capacitor (RLC) circuit were utilized to output bipolar sinusoidal pulse voltages. Through experimental testing, the power supply was able to provide a 420 V (±210 V) peak-to-peak sinusoidal RF high-voltage signal at 1 MHz. On a lab-built instrument platform based on traveling wave-based structures for lossless ion manipulations (TW-SLIM), the influence of the RF voltage amplitude and frequency on the transport efficiency of small molecule ions was investigated using dimethyl methylphosphonate (DMMP) as an analyte. The results showed that both the amplitude and frequency of the radio frequency power supply can affect the ion transport efficiency of the TW-SLIM structure, and there is an ideal range. These findings align with the outcomes of COMSOL simulations. This RF power supply can support the TW-SLIM platform in an efficient manner and is highly valuable for developing compact portable research equipment based on SLIM.