RF Electronics Chapter 6: Oscillators Page 195
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Figure 6.37. Resonator Width and Length Calculation
Since a full SPICE model is not available for the MAR6, only a linear analysis of the
oscillator can be carried out. The circuit schematic for the oscillator is shown in
figure 6.38. This design was produced in early 2005 and presented at [8]. At that time the
more advanced X models were just becoming available and as a result MTEE, MCROSS
and MLEF elements were used. For current designs, the more advanced EM based
MTEEX, MCROSSX and MLEFX elements should be used. In addition Rogers had not
yet suggested that Er = 3.55 should be used for simulation of RO4003 substrates, so the
value Er = 3.38 was used in this design. To enable a comparison between the simulations
and measurements to be made, the results in figures 6.41 to 6.45 are obtained from the
original design.
Figure 6.38. Circuit schematic for 1GHz oscillator.
Figures 6.39 and 6.40 show the circuit diagram and layout of the resonator. A capacitor
is incorporated. That capacitor can be replaced with a variable capacitor in the hardware,
to allow the oscillator to be fine-tuned to the correct frequency. With a minor
modification, this can be replaced with a varactor diode, to enable the oscillator to be
phase locked or frequency modulated.
Figure 6.39. Circuit Schematic for 1GHz Microstrip resonator.
RF Electronics: Design and Simulation
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