High power microwave generation by virtual cathode oscillator

Feasibility Study of Axially- Extracted Virtual Cathode Oscillator

“…Therefore, if the electron energy is modulated at the given frequency, both the virtual cathode position and reflected beam current will oscillate at the same frequency [4,[9][10][11]23]. The electrons energy can be modulated by an electromagnetic field and the same field may interact with the modulated reflection current because they have the same frequency.…”

“…As a result of the positive potential on the anode, the electrons do not leave the system but rather oscillate between the real and virtual cathodes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The microwave emission is attributed to the phase bunching of the oscillating electrons inside the potential well of the system [2][3][4][5][6][7].…”

“…The microwave emission frequency from the virtual cathode oscillator is usually explained by two dynamical mechanisms [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]: first is by the oscillating virtual cathode in the space and time with a well-defined period. This oscillation results in severe longitudinal charge bunching and second mechanism is the trapping of the electrons in the potential well formed between the real and virtual cathodes.…”

“…The virtual cathode plays the role of converting the energy modulation of the injected beam to the current modulation of the reflected beam [11]. It has been common recognition that the microwave emission was attributed to the phase bunching of the reflexing electrons inside the potential well formed between the cathode and virtual cathode as well as oscillation of the virtual cathode itself, both mechanisms coexist in the virtual cathode oscillator [8][9][10][11]. For the reflexing mechanism, the phase bunching of the reflexing electrons is due to the energy dependences of the electron reflex frequency [4][5].…”

“…Among the several types of pulsed high-power microwave generators, the virtual cathode oscillator has been considered very attractive because of its conceptual and mechanical simplicity, high output power capability [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and possible wide-bandwidth with frequency tunable characters which make it attractive for applications where the highpower and wide-bandwidth is acceptable. This device is based on a special class of the bremsstrahlung radiation of the relativistic electrons oscillating axially in the electrostatic fields [4,5].…”