Suppression of a Long-Term Instability of a Commercial Magnetron With Low-Ripple DC Power Supply for Heater

Abstract

Compact but powerful and efficient magnetrons are in service for various high-power microwave applications owing to their additional superiority of low-cost mass production. However, the magnetron's inherent instability in frequency and phase over a relatively wide spectrum limits the versatile availability of the magnetron for possible advanced applications, including a long-distance wireless power transfer system (WPTS) that employs the magnetron as a unit source of a phased array system. The authors present a methodology suppressing a long-term instability of the S-band commercial magnetron harnessed by the phase-locking-loop (PLL) injection controlling and fixing the phase and frequency of the magnetron to the extent of the precision for a WPTS. The long-term drift of the phase exactly replicating the anode voltage fluctuations is successfully suppressed by the implementation of a DC power supply to compensate the cooling effects of the heater, which contributes to extreme stabilization of the phase (peak to peak 0.2 • ) for high-power (1kW). And eligibility for the unit source of a phase-arrayed WPTS is proven by varying the output power while maintaining the phase at a constant.INDEX TERMS Magnetrons, noise, phase-locking-loop (PLL), series parallel resonant converter (SPRC), cooling effect.

Uniformity enhancement of a microwave surface-wave plasma by a field agitation

“…17,18) Adding a PLL to MGT resolves this issue and allows precise control over both the phase and the frequency of MGT, resulting in high stability in control of the phase and frequency. 19,20) The operating system, including the high voltage and cathode heater power sources for the PLL-injected MGT, is the same as the one used in the previous study. 21) Also, the experimental components for the phase control system are the same as the ones used in the previous study.…”

Phase-transition time of a commercial magnetron driving a surface-wave plasma load

“…8) The conditions of the high voltage and cathode heater power sources are optimized for stable phase-locking such as the previous study. 7,8) The photographs of the simple water load and plasma load system are shown in Fig. 2.…”

“…3,4) To overcome this challenge, phase-locked-loop (PLL) injected MGTs based on the van der Pol oscillator model and the Alder equation have recently been investigated, 5,6) which resulted in various methods to precisely control the frequency and phase of MGTs. [7][8][9] PLL-injected MGTs with high stability in-phase and purity in frequency are expected to be employed in microwave plasma (MWP) systems as well for semiconductor processes such as plasma enhanced deposition and etching. 10,11) MWP has the superiority of generating relatively higher plasma density than RF plasmas.…”

“…Model (manufacturer) Magnetron (MGT) 2M137-IL (MUEGGE) Digital phase shifter (DPS) MAPS-010164 (Macom) Phase detector (PD) AD8302 (Analog devices) Signal generator (SG) N5171B (KEYSIGHT) Power Amplifier (PA) KAH2453-40TS-UNF (KRF) Phase-locked loop (PLL)Home-made[7][8][9] …”