Microwave and Wireless Communications Technology

308 MICROWAVE DIODES

Rs L s

,J

v 1 i

Figure 15-12

(A) (B) Tunnel diode equivalent circuit.

The tunnel diode will oscillate if the total reactance is zero

(XL- Xc = O) and

if the negative resistance balances out the series resistance. We can calculate two

distinct frequencies with regard to normal tunnel diodes:

resistive frequency (Fr)

and the

self-resonant frequency

(F~). These frequencies are given by

Resistive frequency

1 I R _ 1 (15- 5)

Fr =

2~r R~

Self-resonant frequency

.$ ~-

ill

2rr, LsCj

1

(RCj) 2

(15 -6)

where

F r

= resistive frequency in hertz (Hz)

Fs = self-resonant frequency in hertz (Hz)

R = absolute ...