| 摘要 |
A linear beam amplification device includes an axially centered electro n emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification devic e comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavi ty and is in electrical communication with an interaction region defined betwee n the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron. The high surface resistivity tends to reduce the Q (quality factor) of the grid-anode cavity, which also reduces the impedance of the grid-anode cavity. Alternatively, the grid-anode cavity may be tuned to define a transmission line having an electrical length approximately equal to n.lambda./4, where .lambda., is the wavelength of the input RF signal, and n is an even integer.
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