26 ELEMENTS OF AIRBORNE RADAR SYSTEMS DESIGN PROBLEM 



1-6 OPERATING CARRIER FREQUENCY 



The operating frequencies for radar systems cover an extremely wide 

 band, ranging from below 100 to above 10,000 Mc. This range is divided up 

 into bands designated P, L, S, X, K, Q, V, and W as shown in Fig. 1-21. 



100 80 60 50 40 30 20 



I I I I I I I I \ L 



WAVELENGTH - Cm 

 10 8 6 5 4 3 



I I I I I I I L 



1 0.8 0.6 



Mill I 



0.4 0.3 



J I 



100 



0.5 0.6 



3 5 6 10 



FREQUENCY - KMc 



20 30 



50 60 



BAND DESIGNATION 



TV 



m 



i 



I 



in 



USE ALLOCATION 



□ 



Allocated to Armed Forces and Other 

 Departments of the U.S. Government 



Allocated to Radio Navigation, Radio Location, and Civilian 

 Radar. Sometimes Used By Military Equipments. 



Allocated to Television, Common Carriers, Domestic Public, 

 Industrial Safety, and International Control. Military Equipments 

 Precluded from These Bands Except at Times of National Emergency. 



Fig. 1-21 Operating Radar Frequency. 



The specific frequencies available for airborne radar systems are, in general, 

 regulated by the Federal Communications Commission during times of 

 comparative peace. 



The operating carrier frequency has a profound effect on the following 

 characteristics of a radar system: 



1. Size, weight, and power-handling capabilities of the RF com- 

 ponents (see Chapter 11) 



2. Propagation of RF energy (see Chapter 4) 



3. Scattering of RF energy (see Chapter 4) 



4. Doppler frequency shift from a target moving relative to the radar 

 direction of propagation. 



These characteristics vary quite radically over the range of radar 

 operating frequencies — enough, in fact, that it becomes convenient to 

 classify a radar according to its operating carrier frequency. This method 

 of classification is commonly used by microwave component designers 



