Nippon Electric Co., Ltd.

Nec Corporation

Takao Kageyama

Yosihiro Morizumi

Hiroshi Kato

Yoshiaki Suzuki

Eiichi Watanabe

Ryuzo Orui

Toshinori Horigome

Kunio Tsutaki

A helix type traveling wave tube comprises an evacuated envelope containing an electron gun assembly at one end thereof for forming and projecting a beam of electrons over an elongated beam path to an electron collector electrode at the opposite end of the envelope. A helix slow-wave circuit is arranged along the beam path intermediate the electron gun and the beam collector for electromagnetic interaction with the beam. In order to extract an amplified signal from the downstream end of the slow wave circuit, there is provided an coaxial line including an outer conductor air-tightly fixed at one end thereof to the evacuated envelope and an inner conductor having one end connected to an output end of the slow wave circuit. An output waveguide is air-tightly fixed to the other end of the coaxial line outer conductor in such a manner the other end of the coaxial line inner conductor extending into the output waveguide. Further, a ceramic hollow cylindrical member is positioned in the output waveguide to surround the other end of the coaxial line inner conductor, and is air-tightly fixed at opposite ends thereof to an inner wall of the output waveguide.

Microwave tube with improved output signal extracting structure

Two coupled cavity type, slow-wave circuits are separated, with a drift space section between them. An electron beam and an electromagnetic wave, which do not interact with each other, over a certain length, are in the drift space. A waveguide type non-reflective termination structure has a waveguide axis directed in the same direction as the electron beam and is coupled to the cavity, slow-wave circuits with respect to a high frequency wave disposed in the drift space section. With such a construction, a traveling wave tube is formed with a PPM focusing and with a non-reflective termination structure includes a waveguide member having a through-hole for passing an electron beam and two waveguides formed on the opposite sides of the through-hole. A lossy ceramic member is disposed within one of the two waveguides for a forwardly traveling wave and another lossy ceramic member is disposed in the other waveguide for a backwardly traveling wave. Each of the two waveguides has one end sealingly closed with tapered ceramic members of the forwardly traveling wave and for the backwardly traveling wave secured on the respective waveguide walls. During its propagation, an electromagnetic wave is perfectly absorbed by the lossy ceramic members.

Coupled cavity type traveling wave tube

A multicavity klystron includes a plurality of drift tubes for passage therethrough of a beam of electrons from an electron gun toward an electron collector via a plurality of cavity resonators arranged successively between the electron gun and the collector. One of the drift tubes which is located next to the collector has an inside diameter which is smaller than that of the other drift tubes.

Multicavity klystron

A coupled cavity type traveling wave tube wherein selected matching and main cavities in the tube are provided with a layer of high resistance metal to minimize generation of reflected waves and thereby to achieve stable operation with high efficiency.

The klystron amplifier comprises an input cavity a plurality of intermediate cavities and an output cavity which are arranged along the path of an electron beam for focusing it, and an output waveguide coupled to the output cavity through a coupling opening. The product G.sub.0 (R/Q)Q.sub.ex is selected to be

Multi-cavity klystron amplifiers

A traveling wave tube employing a coupled-cavity type slow-wave circuit and having high gain and efficiency over a wide operating frequency band as a result of a design in which the slow-wave circuits are separated into first and second (i.e. fore) and output slow-wave circuits connected to one another by sever sections containing nonreflectivity terminated waveguides. The synchronizing frequency of one of the fore slow-wave circuits is selected to be different from that of the other fore slow-wave circuit and the output slow-wave circuit. The aforesaid slow-wave circuits incorporate coupler cavities at the opposite ends thereof and a plurality of main unit cavities positioned between the coupler cavities. The desired synchronizing frequencies are obtained by controlling the dimensions of the cavities, interaction gaps, apertures and coupling irises.

Wide-band coupled-cavity type traveling-wave tube

A multi-cavity type velocity modulation tube, operable in the K-band above 10 GHz and having input, pre-buncher, buncher and output cavities which are respectively tuned to frequencies that are higher than the upper end of the operating pass band; near the upper end of the operating pass band and lower than the resonant frequency of the input cavity; higher than the resonant frequency of the input cavity; and within the operating pass band of the tube. The input cavity Q-value is lower than that of the prebuncher cavities. Preferably first and second prebuncher and first and second buncher cavities are provided, the second prebuncher and at least one of the bunchers are unloaded and the second prebuncher is tuned to a frequency in the vicinity of the lower end of the operating pass band. The design yields a low cost tube having a significantly improved gain-bandwidth product.

Wideband multi-cavity velocity modulation tube

In a four-cavity velocity modulation tube comprising an electron gun assembly, an input cavity, a pre-intermediate cavity, a post-intermediate cavity, an output cavity, a collector assembly and drift tubes interposed between adjacent ones of said cavities, said input cavity is tuned to the proximity of the lower end of the operating passband of said velocity modulation tube, said pre-intermediate cavity is tuned to the proximity of the upper end frequency of said operating passband, said post-intermediate cavity is tuned to a fundamental resonant frequency that is higher than the upper end frequency of said operating passband but lower than a frequency which is 1.6 times as high as the center frequency of said operating passband, the normalized length of all of said drift tubes being smaller than 90 degrees in terms of the reduced plasma angle, and the normalized length of the drift tube positioned between said pre-intermediate cavity and said post-intermediate cavity being larger than the normalized lengths of the other drift tubes.

Four-cavity velocity modulation tube

In a velocity modulation tube comprising a floating prebuncher and at least one final prebuncher, frequencies of respective fundamental modes of resonance of the input cavity, the floating prebuncher, and the final buncher are adjusted to the lowest frequency of the passband of the tube, adjacent to the highest frequency of the passband, and higher than the highest frequency, respectively. Furthermore, the Q-value of the floating prebuncher is made equal to or lower than that of the input cavity. Naturally, the output cavity has its fundamental mode of resonance approximately at the center of the passband.

Growing community of inventors

Tokyo, Japan

Takao Kageyama