582 THE. BELL SYSTEM TECHNICAL JOURNAL, JULY 1951 



Fig. 25 — An electromagnetic field pattern of a disk array lens in which the copper foil 

 disks are mounted on polystyrene foam sheets./ = 9,100,000 KC (X = 1.3"). 



Fig. 26— A microwave field pattern of a waveguide type metal lens. Phase has been added, 

 showing the curved wave fronts approaching and leaving the focal point./ = 9.1 KMC. 



the energy is collimated into a beam (Fig. 27). The reference signal for these 

 phase patterns was obtained by the method illustrated in Fig. 28. A second- 

 ary microwave source was employed which was fed from the main source 



