外文翻譯--回旋速調(diào)管彎圓波導(dǎo)模式轉(zhuǎn)換器的分析（原文）

1、The Eighth International Conference on Electronic Measurement and Instruments ICEMI’2007 Analysis of Bent Circular Waveguide Mode Converter for Gyroklystron Song Yuecong Hu Wei (Department

2、of Computer Science mode conversion; coupled wave equations; circular waveguide; phase rematch. 1 Introduction Gyroklystron has the virtue of high peak power, high average power, high gain and suitability bandwidth and

3、so on, very suit for the power source of millimeter wave high capability radar, phase array radar, millimeter wave communication and other systems. But the output mode of gyroklystron is TE01 and TE02, thus very inconven

4、ient for direct use, so it must be taken a mode conversion, especially high power mode conversion. And its mode converter adopt mostly the following sequence[1]? TE0n?gyrotron?—TE01—TE11—HE11?antenna?? ? TE0n ? gyrotron

5、? —TE01—TM11—HE11?antenna? the first sequence has been employed here, adopting perturbation of axis curved, and arriving at an efficient circular waveguide converter with conversion efficiency reaching 98% and bandwidth

6、 exceeding 5%, while its overlength (881.6mm) confines its practice to a limited field with inconvenient machining. Thus the second sequence is chosen to for better usage, with TM11 as the intermediate polarized mode, H

7、E11 the latter one, to radiate outside, Based on the sinusoidal curvature structure improved by the author, is designed and calculated, creating a TE01?TM11 mode converter of 8mm high-power circular waveguide with c

8、onversion efficiency coming to 99%, bandwidth exceeding 32% and length being only 386mm, thus realizing an tighten, efficient mode converter of broad bandwidth. Heavy considerations have been given to the influence of mu

9、ltimode factor, backward wave, ohmic losses carried from metal wall, modes choice and phase rematch. 2 Coupling Wave Theory The unevenness in a waveguide (the bent of axis in a circular waveguide, gradual radius changes

10、of the waveguide) will cause the energy coupling among different propagation modes and thus create mode conversion. The coupling wave equations based on the coupling wave theory are the fundamental equations which study

11、axis curved circular waveguide mode converter [2?3]: ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ?? ? ?? ?? ?mn mn mn n m mn mn n mn m n m n mA C A C jA j dzdA) )(( ) )((?(1) 1-3741-4244-1135-1/07/$25.00 ©2007 IEEE.The Eighth Inte

12、rnational Conference on Electronic Measurement and Instruments ICEMI’2007 extension. So the second conversion sequence is adopted, and use TM11 mode as intermediate polarized mode, then conve

13、rt it into HE11 to radiate outside, during the process of which TE01?TM11 conversion is the most important The geometry structure of TE01?TM11 mode converter with circular waveguide is a bent one. Owing to the same phase

14、 constant in the bent circular waveguide of mode TE01 and TM11, a proper bent waveguide can make them carry out continuous power coupling. Multimode factor, backward wave?ohmic consumption, axis curved and phase rematch

15、etc, have been carefully considered in the calculation. When the incident mode TE01 is input the converter, it couples with TE11, TE12 and TM11 mode, spurious modes TE21 and TM21 carry the secondary coupling. According t

16、o the analysis on the coupling coefficients of these modes, other mode coupling can be out of consideration for their weak coupling and small output amplitude. Thus only TE01, TE11, TE12, TM11, TE21 and TM21 are the focu

17、s here. Meanwhile, in order to lessen the ohmic consumption and enhance the bandwidth, converters must be as short as possible. In paper [6], other coupling mode has been efficiently prevented by a proper change curvatur

18、e of the waveguide, thus increasing the conversion efficiency. Two structures are employed: TE01?TM11 mode converter with constant curvature waveguide and with sinusoidal curvature waveguide. Different from other papers,

19、 sinusoidal curvature structure in equation (8) is accepted to reach a high conversion efficiency with a shorter length and broader bandwidth through optimal calculation, widened curvature range and strengthened input-ou

20、tput mode coupling. It is clear in Fig 2, that the output power of TE11 and TE21 can be efficiently reduced by the improved sinusoidal curvature waveguide, making conversion efficiency increasing from 97% to 99% and the

21、length being lessened much. For mode converters of single bent waveguide, the principles between circular waveguide radius, bent curvature, frequency and bandwidth are the same with double bent structure[6,7]. Under the

22、same frequency, the shorter of the waveguide radius and the length, the greater the mode conversion efficiency. Under the same circular waveguide radius, the greater the operating frequency, the longer the waveguide leng

23、th and the smaller the bent curvature, bandwidth and mode conversion efficiency. 0 2 4 6 80.00.20.40.60.81.0 PsumTE11TE01Fractional powerz/dm0 2 4 6 80.000.020.040.060.080.100.12TM11TE21TE12Fractipnal powerz/dm0.0 0.5 1.