226 REFLECTION AND TRANSMISSION OF RADIO WAVES 



Then Pt may be written as 



kTPlLV<TTFT 



Pt 



\'R' 



(4-79) 



in which h = kb'^/i4T)K 



Plots of Equation 4-76 for a specific sea condition and of Equation 4-79 

 will then be as shown in Fig. 4-45. From this, it follows that the range scale 



Fig. 4-45 Target and Clutter Power Relations vs. Range. 



in which the target-to-clutter ratio may 



REGION 1 



REGION 2 



REGION 3: 



kahLR 



kahLR 



(4-80) 



may be divided into three regions, 

 be expressed as follows: 



Pt 

 Pc 



Pt 

 Pc 



Pt 

 Pc 



Obviously, a large antenna width and a short pulse length will increase 

 the target-to-clutter ratio in all three regions. Furthermore, if or is inde- 

 pendent of frequency, then so is Pt/Pc in regions 1 and 3. The locations of 

 the transition ranges Rt and Re can be controlled by the height h of the 

 radar. It is evident from Fig. 4-45 that the largest target-to-clutter ratios 

 generally will be obtained in region 3. 



Since region 3 is one in which destructive interference operates on both 

 the target and clutter signals, this is a region of relatively low signal 



\2hHuio) 



arL ( SHt Y 

 kahLR\2H,i,,)- 



