WAFER TYPE MILLIMETER WAVE RECTIFIERS 



1393 



150 200 250 300 350 400 450 500 



60-MC INTERMEDIATE FREQUENCY IMPEDANCE, Z|p, IN OHMS 



Fig. 10 — Sixty-megacj'cle intermediate-frequency output impedance (Zif) 

 for 100 wafer units with one milliwatt beating oscillator drive (average 338 ohms) 



limit of 8.5 db was arbitrarily adopted. This required the readjustment 

 of eleven units, with a new point inserted in each case. No units were 

 rejected because of high noise and none of the hundred units processed 

 was lost. 



From the bar graphs it may be seen that the wafer units have the 

 average characteristics shown in the accompanying table at a wave- 

 length of 5.4 millimeters.* 



Conversion Loss L 7 . 2 db 



(5.3 times) 



Noise Ratio A^r 2.2 times 



IF Impedance (60 mc) Zj-p 338 ohms 



Knowing the noise figure, Nif , of the IF amplifier intended for use 

 with the rectifiers, the overall receiver noise figure, A^rec > may be cal- 

 culated by the following formula (using numerical ratios) : 



NnKc = L(N,, - 1 + A^if) 



Assuming an IF amplifier noise figure of 4.0 db (2| times) and the 

 average values of "L" and 'Wr" given above for the millimeter wafer 

 units, we have for the case of a noiseless beating oscillator; 



ATrec = 5.3 (2.2 - 1 + 2.5) ^ 20 (13 db) 



* A few wafer units have also been measured at a wavelength of 4.16 millimeters. 

 The conversion losses averaged about 1.6 db greater than those measured at a 

 wavelength of 5.4 millimeters. 



