SILICON CRYSTAL RECTIFIERS 



27 



a factor of approximately 2.5 giving a net improvement in rectification ratio 

 of 50 to 1. The parallel improvement in receiver performance resulting from 

 process improvements is shown in Fig. 15. A comparison in power handling 



ui a. 



UJ u. 



a. r 



D \iS 



il< 



Q 

 UJ UJ 



o tr 



ZUJ 



cnz 



UJ (J 



cr UJ 



10-2 



\0-^ lO"'* 10" 



CURRENT IN AMPERES 



10-2 



Fig. 14 — Improvement in the direct-current rectification characteristics of 

 sihcon crystal rectifiers in a four-year period. 



10,000 MEGACYCLES 



3000 MEGACYCLES 



OCT 

 1942 



DEC 

 1942 



MAR APR 

 1945 



* note: — 6 DECIBELS IS THE MINIMUM RECEIVER-NOISE 

 FIGURE ATTAINABLE WITH A DOUBLE DETECTION RE- 

 CEIVER EMPLOYING A CRYSTAL CONVERTER AND A 

 5-DB INTERMEDIATE-FREQUENCY AMPLIFIER. 



Fig. 15 — Effect of continued improvement in the crystal rectifier on the 

 microwave receiver performance. The noise figures plotted are average values. 



ability of the 3000-megacycle converter types made by the improved pro- 

 cedures and the older procedures is shown in Fig. 16. 

 The flexibility of the processes may be illustrated by comparison of two 



