40 



STANDARD PROPAGATION 



10,000 



1000 



to 



<t 

 u 



I- 

 bJ 



O 



UJ 



x 



100 



10 



-200 



-180 



-160 



-140 



-120 



-100 



80 



OB 



Figtjhe 13. Field strength versus height of receiver for fixed distance relative to radiation field at one meter from 

 transmitter. 



theory in its present form as applied to short and 

 microwave propagation has been worked out by 

 van der Pol and Bremmer 20 for vertical polarization 

 and Marian C. Gray for horizontal polarization. 



The results of the theory may be summarized as 

 follows. The electromagnetic field can be represented 

 as an infinite series of the form 



E = E Vd ^ c m e-Ud U m (h) U m (h 2 ) 



(27) 



where E is the free space field and c m and f m are 

 complex constants depending upon |the wavelength 

 and the electromagnetic ground constants, hi and h* 

 are again the heights of the transmitter and receiver 

 above the ground, d is the distance between the two; 

 U m are the height-gain functions, and e is the base 

 of natural logarithms. The formula is symmetrical 

 with respect to the interchange of transmitter and re- 

 ceiver, in agreement with the principle of reciprocity. 



