Abstract: An electron beam tube includes an electron gun included within a vacuum envelope defined partly by a ceramic cylinder. The ceramic cylinder includes straight sided portions and with an intervening conical section between them. The straight sided portions and form part of two r.f. chokes, being metallized on their inner and outer surfaces and forming a connection with a cavity forming part.

Abstract: This device allows the variation of the coupling between two points in an RF circuit in a very simple way while maintaining the RF phase relationship and varying the relative magnitude of the RF fields. The device is characterized by a simple mechanical control of coupling value, that has negligible effect on the phase shift across the device. This is achieved by the simple rotation of the polarisation of a TE111 mode inside a cylindrical cavity. Such a device does not contain resistive elements, and the sliding mechanical surfaces are free from high RF currents. This device finds an application in standing wave linear accelerators, where it is desirable to vary the relative RF field in one set of cavities with respect to another, in order that the accelerator can operate successfully over a wide range of energies.

Abstract: In a field emission cathode emitting an electron beam modulated by any desired high frequency, a cathode tip is formed in one surface of an N type semiconductor substrate constituting a collector region, an insulating layer formed on the one surface of the semiconductor substrate to have an opening which surrounds said cathode tip, a gate electrode is formed on the insulating layer to have an opening which surrounds the cathode tip, a P type base region is formed in the other surface of the semiconductor substrate, a base electrode is formed on the base region, an N type emitter region is formed in the base region, and an emitter electrode is formed on the emitter region. A DC supply source is connected across the gate electrode and the emitter electrode and a high frequency supply source is connected across the base electrode and the emitter electrode.

Abstract: A low-power wide-bandwidth klystron comprises a cathode having an electron emitting surface capable of emitting an electron beam and a collector spaced from said cathode and designed to collect the electron beam emitted from the cathode. An anode is disposed between the cathode and the collector in order to channel the electron beam into a series of drift tubes that define the electron beam path between the anode and the collector. The drift tubes define gaps in which the input cavity and output cavity interact with the electron beam. The input cavity velocity modulates the electron beam by way of a radio frequency input signal and the output cavity extracts the amplified radio frequency signal from the electron beam. The drift tubes may define additional gaps between the input cavity and output cavity for intermediate cavities that would provide additional amplification.

Abstract: A standing wave accelerator structure that has both inline coupling cavities and side coupling cavities combined into one structure. Additionally, the invention uses a prebunching (re-entrant) cavity, excited electrically or magnetically, through apertures between a first accelerating cavity and the prebunching cavity.

Abstract: A coupled cavity circuit for a microwave electron tube comprises at least two resonant cavities adjacent to each other. An electron beam tunnel passes through the coupled cavity circuit to allow a beam of electrons to pass through and interact with the electromagnetic energy in the cavities. An iris connecting the adjacent cavities allows electromagnetic energy to flow from one cavity to the next. The iris is generally symmetrical about a perpendicular axis of the electron beam tunnel with the iris having flared ends and a central portion connecting the flared ends. The iris shape causes the iris mode passband to be lower in frequency than the cavity mode passband while still providing broadband frequency response.

Abstract: A resonant cavity is coupled in series with an output waveguide of a klystron in order to enhance power within an operating band of the klystron. The response characteristic of the resonant cavity enhances the power at certain frequencies within the operating band of the klystron, e.g., at the high or low ends of the operating band, by intentionally creating a power mismatch at these certain frequencies while providing minimal effect on the power at other frequencies of the band. The resonant cavity is inductively coupled to the output waveguide through an iris that sets the phase of the reflection by virtue of its location in relation to the klystron output gap and the magnitude of the reflection by virtue of its size. A tuning apparatus may also be used for tuning the resonant frequency of the resonant cavities. Plural resonant cavities may also be utilized to provide power mismatches at plural portions of the klystron operating band.