Research Of Ferroelectric Cathode For Virtual Cathode Oscillator

As a promising High Power Microwave ( HPM ) generating device, Virtual Cathode Oscillator (VCO) has been studied world widely. It shows great potential in practical uses because of its unique features, such as simplicity of the structure, no requirement of magnetic field, and high power output. Meanwhile, enhancements of the efficiency and suppressions of the pulse shortening are the main obstacles in the application of VCO. In order to achieve these goals, a cathode with uniform and fast rising time electron emission is needed. Since the Ferroelectric Cathode (FEC) could meet these requirements, we tried to adopt FEC in VCO.First of all, a ferroelectric cathode diode was fabricated. And the studies of the uniformity and the rising time of the electron emission from FEC were carried out using this diode. The uniformity and rising time of the electron emission had been measured under different peak values of the triggering pulse and different delay times between the triggering pulse and the accelerating pulse. The current density distribution of the emission from FEC was also studied on this set of devices.To obtain the inward coaxial emission of FEC, a coaxial FEC diode was fabricated. This step played an important role in the application of FEC in VCO. With this coaxial diode, the"self-triggering"was studied, and a simplified method of using FEC was developed.The virtual cathode oscillator with a ferroelectric cathode was produced based on PIC simulation. And the uniformity of the electron emission from velvet cathode and ferroelectric cathode was compared using these devices. And FEC was proved to be a competitive cathode for VCO.