| 摘要 |
858,288. Travelling wave tubes. SIEMENS & HALSKE A.G. April 4, 1957 [April 6, 1956], No. 11077/57. Class 39(1). In a travelling wave tube having an interdigital delay line the cross sectional area of the electron beam is small relative to the cross sectional area of the field of the interdigital delay line and the beam is located solely in a region in which a particular frequency harmonic of the fundamental space wave predominates. The beam is adjusted to travel in the correct region by electron optical or mechanical means. The electron optical means consists of deflecting means and the mechanical means consists of means for relative adjustment of gun and delay line. The delay line is preferably a flat interdigital line of width less than #/1 and the tube functions as a backward wave oscillator, a flat electron beam passing to one side of the line and if desired a second flat beam passing on the other side of the line. The field amplitudes along different longitudinal sections of the delay line are plotted for frequencies f, 2f and 3f in Figs. 2a, b, c, respectively (not shown). For frequency f the fundamental component is mainly at the central region IV, Fig. 1, of the delay line, the frequency harmonic content increasing, and the fundamental content decreasing, in both directions away from the central region IV. For an operating frequency of 2f this wave predominates in regions II and VI and for a frequency of 3f this wave predominates in region IV and between regions I and II ; and VI and VII. For frequency f therefore a high current small diameter beam flows along region IV for 2f along II or VI and for 3f between regions I and II or VI and VII. |
