MICROWAVE PARAMAGNETIC RESONANCE ABSORPTION 



455 



(a) 



Rl.= Ro 

 DETECTOR 



(b) 



Fig. 3 — Equivalent circuit for a transmission cavity. 



to determine whether the cavity is overcoupled or undercoupled. This 

 information may be necessary in Qo determinations.^- 



B. Transtnission Cavity 



Fig. 3 shows the equivalent circuit for a transmission cavity, the 

 generator and the detector being matched to the waveguide, i.e., 



Rg = Rl = Ro 



Analogous to the reflection cavity we define again two coupling coeffi- 

 cients 



^1 = 



RoUi 



/32 = 



R(>ni 



r r 



the relation between the unloaded and loaded Q being 



Qo = Ql(1 + iSi + /32) 

 1. Detector Output Proportional to Input Power 



(18) 



(19) 



Power into load Pl = 



Tr2 "* ''t-> 



V Hi iii'Ro 



(i?or?i2 + r + Roni^y 

 (Vn,y 



Max. power generator can deliver Po = 



dr 



2V\i niRo 



{Ro7h' + r + RoUi') 



4(ni2/?o) 

 A/- 



(19) 



