UDC 621.365.5
Designing a slow-wave system for TWT Ku-band
with a frequency band 16.5% and a gain of at least 30
dB
S. V. Zharihin, V. I. Panitskov, T. I. Polyanskaya
JSC "SPE " Shokin Istok" Vokzalnaya
st. 2a-1, Fryazino, Moskow region 141190, Russia
The paper is received on June 14, 2019
Abstract. This article presents results of the
design of a slow-wave system on coupled cavity circuit (CCC) of the Ku-band
with operating frequency band 16.5% with output constant power of several kW
and a gain of at least 30 dB. Variants of the slow-wave system(SWS) are
considered, the optimal cutoffs of the sections of the slow-wave system, slope
of the dispersion characteristics of the input and output sections, as well as
the cutoffs and the period of the middle section are determined.
As a result of the calculations, 3 variants of
projects of partitioned slow-wave system for TWT were obtained.
Option 1: 3-section SWS based on CCC with a resonator
type of wave in the main passband; slow-wave system is designed for
undervoltage and increased perveance: slow-wave system voltage Usw = 14 kV ±
1%, cathode current Icat. = 2.3 A;
Option 2: 3-section slow-wave system on the basis of a
SWS type CCC with a resonator type of wave in the main passband: a voltage of
slow-wave system Usw = 18.8 kV ± 1%, the cathode current Icat. = 1.7 A.
In both cases, the output section of the TWT has a
flat dispersion characteristic, which may require additional design measures in
the node of the output section to eliminate spurious generation in the high-frequency
region of the main bandwidth. In addition, in version 1, difficulties may
arise with focusing a high- perveance electron beam.
Option 3: 4-section slow-wave system based on SWS type
CCC with a slit type of wave in the main passband; Usw = 18.85 kV ± 1%, cathode
current Iсat. = 1.7 A. The output section has a rather flat dispersion
characteristic, with a slope characteristic of broadband TWT on SWS of counter
pin structures type; No special measures are needed to suppress parasitic
generation in the high-frequency region of the base bandwidth of the SWS,
however, the total length of the partitioned SWS has increased significantly by
adding another section.
Building, configuring, and testing high-power
continuous broadband TWTs is a fairly time-consuming process. This was
demonstrated by the experience in the development and production of TWTs, the
operating frequency bands of which approach 10% and are already quite wide with
the required output parameters and mass-dimensional characteristics. The
increase in the working frequency band of more than 1.5 times significantly
increases the complexity of its manufacture. How much is surmountable and
which of the three options for SWS should preferably be shown by an
experimental study during a specially designed work.
Key words: powerful broadband TWT, coupled
cavity circuit and counter pins, zones of generation, main band, amplitude-frequency
characteristics.
References
1. Zharihin S.V. Panitskov
V.I. Polyanskaya T.I, Stroykov E.A. Features of the development of high-power
wideband TWT on the sectioned counter pin slowing structures and a coupled
cavity circuit with a magnetic periodic focusing system.” Proceedings of VI
All-Russian Conference Electronics and Microelectronics Microwave”, 2017,
St. Petersburg, Saint Petersburg Electrotechnical
University "LETI"