Abstract:
Background High power microwave (HPM) pulse technology has developed rapidly due to its applications in particle accelerators, radar, communications, directed energy, plasma physics, and other fields. Pulse compression technology provides an effective method for enhancing the peak power of microwave pulses.
Purpose In order to study a low-cost, miniaturized, stable, and arrayable SLAC Energy Doubler (SLED) based on vacuum electronic oscillators such as magnetrons, a high power fast bi-phase modulator with megawatt-level capacity and nanosecond response time has been designed.
Methods Insert a conventional PIN diode loaded-line type phase-shifting circuit into the waveguide structure, and the equivalent impedance of the phase-shifting circuit changes by switching the “on” and “off” states of the PIN diodes through the waveguide external bias circuit, then the waveguide transmission microwave phase changes. The high-power characteristics of such PIN diode waveguide phase shifters have been verified by high-power experiments.
Results In this paper, a 180° phase shift is realized by cascading 8 phase-shifting circuit cells. The frequency-domain and time-domain parameters of the designed bi-phase modulator are tested. The frequency-domain test results show that the insertion loss of the bi-phase modulator is less than 0.7 dB, and the phase shift is 172° at the center frequency of 2.458 GHz. The error of the phase shift is within ±4° compared with that of the design value in simulation. The time-domain test results show that the inversion time of the bi-phase modulator is about 5 ns.
Conclusions Compared with traditional semiconductor phase shifters, this bi-phase modulator can achieve the same phase-reversal speed while withstanding high power capacities, making it extremely valuable in the HPM field.
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