Microwave and Wireless Communications Technology

6 INTRODUCTION TO MICROWAVES

c

'~ = F-q~ (1-2)

and

c

F = X.qf-~ (1-3)

All terms are as defined for Eq. (1-1).

A design standard requires that a parabolic-dish microwave antenna used in

communications or radar be built with a surface smoothness of 1/12 wavelength.

For a 2.2-GHz signal, therefore, the surface should be built to within 13.6 cm/12, or

1.13 cm of the mathematically exact curve. Some of these antennas have diameters

on the order of 15 meters (1,500 cm), so you can see the precision to which the par-

abolic shape must be maintained: this is one reason why microwave design can be

difficult.

The wavelengths of microwave ...