RF Electronics Chapter 6: Oscillators Page 200
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Figures 6.47 and 6.48 show the corresponding coupled dual resonator. As described
above, this design was done early in 2005 [8] and the more advanced EM based
Microstrip elements were not used. Like the tuning carried out on the single resonator
shown in figure 6.39, the lengths of TL2 and TL13 of the double resonator are adjusted
to minimise the loading on the resonator by the amplifier, while still giving the correct
open loop gain, corresponding to the switch in figure 6.1 being open. Thus producing a
result similar to figure 6.42 for the single resonator design using OSCTEST.
Figure 6.48. PCB layout of for the dual resonator of figure 6.47.
An oscillator using a MAR6 amplifier, similar to figure 6.43 and 6.44, is designed and
the lengths of TL2 and TL13 and the value of Rc are adjusted to ensure an open loop gain
slightly greater than 0 dB and the length of the transmission lines making up the feedback
loop are adjusted to give a 0 phase shift.
Figure 6.49. Comparison of single and dual resonator open loop gain and phase.
RF Electronics: Design and Simulation
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