p. J. ALLEN 



M. S. WHEELER 



CHAPTER 10 



ANTENNAS AND RF COMPONENTS* 



Symbols Used in Chapter 10 



of angular error 

 minimum detectable signal 

 group velocity 

 phase velocity 



attenuation constant 

 phase constant 

 propagation constant 

 relative dielectric constant 

 or permittivity 

 d angular displacement from 

 the parabolic centerline 

 beamwidth 



lobing angle (squint angle) 

 free-space wavelength 

 cutoff wavelength 

 wavelength in transmission 

 line 



relative permeability 

 target back-scattering cross 

 section 

 angular frequency (2irf) 



There is at the front end of a radar receiver an almost one-to-one analogy 

 with components of a conventional communications receiver. The only 

 reason for the difference in appearance of this section of the radar as 

 compared with the communications receiver is the difference in frequency 

 handled at the antenna and at the input to the receiver. Both receivers 

 are usually heterodyne receivers and for much the same reason. As such^ 

 a local oscillator and mixer are involved. In the radar receiver, the locaj 



♦Paragraphs 10-1 through 10-9 are by M. S. Wheeler. Paragraphs 10-10 through 10-20 are 

 by P. J. Allen. Paragraph 10-21 is by Dr. P. M. Pan. 



511 



