MAGNETRON AS GENERATOR OF CENTIMETER WAVES 237 



Zl , are reflected into the primary circuit. It may be shown^' that the 

 circuit of Fig. 31 (b) is the equivalent of that of Fig. 31 (a). The coupUng 

 into the primary circuit is represented by an ideal transformer connected 

 across the primary inductance L to the secondary winding of which are 

 connected the load impedance Zl and a reduced loop reactance 



Xo = jcoLf 



L 



LLo) 



The ideal transformer effects a voltage transformation of — - : 1 or an ad- 



M 



(?) 



mittance transformation of ( — 1 : 1 from its secondary to its primary 



terminals. Thus, the admittance, Yl , presented at the primar>' terminals 

 of the ideal transformer, is 



(32) 



=ey--(?j<<^''+^--' 



in terms of the admittance Fl at the secondary terminals. 



The equivalent circuit has now been reduced to that of Fig. 31 (c) used 

 earlier in the discussion of a single resonator of the magnetron resonator 

 system. Each of the quantities defined or derived for this circuit are now 

 to be applied to the magnetron resonator system as a whole. These include 

 the characteristic admittance of the resonator, Fo , the unloaded, loaded, 

 and external Qs given by the relations (21), (22) and (23), and the circuit 

 efficiency, tjc , of equation (25). 



Looking to the left at the terminals AB into the electron stream one sees 

 the electronic admittance Ye = Ge-\-jBe. This is defined in terms of the cur- 

 rent, Irp , induced in the anode segments by the electrons moving in the 

 interaction space, and the RF voltage, Vrf , appearing across the resonators, 

 that is, across the terminals AB of Fig. 31 (c). Looking into the circuit 

 at the terminals AB one sees the admittance F, . 



This admittance by equations (19) and (32) is 



F. = G.+y2Fo.'^^^^''+Fl' 



OJo 





(■^)(Gl+iBl). 



" See Guillemin, Communications Networks, Vol. II, p. 154. 



