Microwave and Wireless Communications Technology

Affenuators 147

C ~, 0 C

O

(A)

O O

R 1

(B)

R2

0

_.L/

T/

(C)

C

(D)

O

~ i ~ i ~

C - - O

(E)

Figure 7-5

Attenuator circuits: A) series in-

line resistor; B) resistor voltage

divider; C) capacitor voltage

divider; D) T pad; E) pi pad.

shown in Fig. 7-5A. This attenuator is a resistance in series with the line and so ab-

sorbs power and thereby provides attenuation.

The second form is the inaptly named

minimum loss

attenuator of Fig. 7-5B.

This attenuator is primarily used in voltage signal systems where impedance

matching is not the issue. The attenuation ratio is determined by the voltage-divider

equation

[VR2/(R1 ...