STANDING-WAVE ANTENNAS 



31 



vantage of being insensitive to small changes in 

 frequency and at the same time are not so subject to 

 corona (breakdown of the air because of large poten- 

 tial gradients) as slender antennas are. 



Standing-Wave 



V Antennas 



This type of antenna (Figure 18) utilizes the 

 directive properties of the multi-half-wave antenna. 



Two such elements are combined in a V arrange- 

 ment so that the major lobe of each (at azigle a with 

 each element) is parallel to the axis of the V. By 

 feeding the two halves of the V with currents 

 180 degrees out of phase the lobe structure is reversed 

 to produce maxima, forward and backward, along 

 the axial direction, while the field in the plane 

 perpendicular to the axis is greatly reduced. The 



AXIS 



Figure 18. Standing-wave V antenna (a= 36° for n = 4 lialf-wavelengtlis). 



IN PLANE OF THE V IN PLANE -L TO V 



n = 16 , tf = 17.5° n="6 . 0f=l7.5° 



Figure 19. Power distribution for standing-wave V antenna. (Courtesy of IRE ) 



