A COUPLED RESONATOR REFLEX KLYSTRON 765 



Qualitative and quantitative experimental verifications of the theory 

 were undertaken and good agreement obtained. Oscillograms of mode 

 shapes having a range of constant power output and wide half-power 

 electronic tuning were presented together with a number of applications 

 of the coupled resonator reflex klystron both as a microwave and as an 

 intermediate frequency sweep source. Other applications were indicated 

 and additional ones may suggest themselves to the reader. 



It is believed that the addition of the second resonator makes the 

 reflex klystron a more useful device in many of its more important 

 applications. 



ACKNOWLEDGEMENTS 



The writer wishes to express his appreciation to J. 0. McNally for 

 the advice and encouragement received in the execution of this work. 

 The assistance of the thesis advisor, Prof. John B. Russell of the Elec- 

 trical Engineering Department of Columbia University, is also grate- 

 fully acknowledged. 



REFERENCES 



1. Pierce, J. R., and W. G. Shepherd, Reflex Oscillators. Bell System Tech. J., 



26, pp. 460-690, July, 1947. This reference constitutes a very complete treat- 

 ment of reflex klystron theory and practice. The derivation of the expression 

 for electronic admittance is given in Appendix III, pages 639-643; of particu- 

 lar interest to the coupled resonator reflex klystron is Pierce and Shepherd's 

 treatment of Frequency Sensitive Loads and Long Lines Effects, pp. 523, 

 where it is shown that certain load conditions encountered in the operation 

 of reflex klystrons may result in load hysteresis similar to the one described 

 in the preceding paper as due to an overcoupled secondary resonator. 



2. Martin, R. A., and R. D. Teasdale, Input Admittance Characteristics of a 



Tuned Coupled Circuit. I. R. E., Proc, p. 57, January, 1952, and correction 

 to this paper published in I. R. E., Proc, p. 459, April, 1952. This paper 

 presents a precise expression for the input admittance of two coupled 

 resonant circuits and gives plots of specific numerical examples. The expres- 

 sion for input admittance given in the above named correction reduces to 

 equation (3.2) and (3.12). 



3. Bleaney, B., Electronic Tuning of Reflection Klystrons. Wireless Engineer, 



p. 6, Jan., 1948. A valuable background paper on the mechanics and maximi- 

 zation of electronic tuning. 



4. Very High-Frequency Techniques, Vol. II, Radio Research Laboratory, 



Harvard University. (McGraw-Hill). Chapter 31, p. 849 contains a concise 

 and valuable treatment of reflex klystron theory. It leads up to the appli- 

 cation of external-cavity reflex klystrons in wide tuning range coaxial 

 resonators. In the course of explaining some load hysteresis phenomena 

 which are sometimes caused in these circuits by parasitic resonances or 

 excitation of undesired modes, a simplified expression for the input ad- 

 mittance of two coupled resonators is given. This expression is similar to 

 equation (3.12). An experimental method is also suggested (p. 869) to meas- 

 ure the coupling coefficient between the main resonator and the undesired 

 resonance. Use has been made of this method in the calibration of the 

 secondary resonator in Section 4.3.2. 



