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TECHNICAL MEMORANDUM Page 7 of 12 has been observed is the oscillation cycle of start, saturation and subsequent quenching. The quenching or extinguishing of the oscillator is believed to be related to this phenomenon. The common collector oscillator was further explored using the coupled transmission line as a parametric variable. The parameters of output power, phase noise and load line were documented for various coupling values. V. SIMULATION RESULTS The simulation algorithm begins with a frequency search of the required conditions for oscillation under small signal conditions and proceeds to find a large signal, steady-state solution at the identified spectral areas using a probe element as described in Appendix B. The simulation data is graphically summarized within the following illustrations: Figure 8: Spectral Content at V t =4.0 Vdc. The spectral content graphic shows the strong second harmonic as expected with fundamental, third and fourth harmonic levels present. Figure 9: Power Output versus Tune Voltage The oscillator power output remains constant within 0.25 dB over a voltage tuning range of eight volts. Figure 10: Frequency versus Tuning Voltage The oscillator output frequency (fundamental) versus tuning voltage discloses 250 MHz of voltage tuning over 8.0 Volts. The tuning range is a strong function of the varactor coupling capacitors. A tuning range of 1.0 GHz has been noted with larger coupling capacitors Figure 11: Phase Noise versus Offset Voltage Phase noise of the Push-Push oscillator and the single common- collector oscillator. Because one expects a six dB difference, some noise suppression is indicated. Phase noise -100 dBc/Hz has been measured on the Push-Push configuration indicating excellent correlation. 2 4 6 8 10 12 14 16 18 20 Frequency (GHz) CC PP Oscillator A Spectrum -80 -60 -40 -20 0 20 9.217 GHz 13.7 dBm DB(|Pharm(PORT_1)|)[1,4] (dBm) CC PP Oscillator A p1: FREQ = 1 GHz Vdc = 4 V 1 2 3 4 5 6 7 8 Voltage (V) Power Output vs Voltage 10 12 14 16 18 20 p1 8 V 14.19 dBm 1 V 13.53 dBm 4.003 V 13.72 dBm DB(|Pcomp(PORT_1,2)|)[*,X] (dBm) CC PP Oscillator A p1: FREQ = 1 GHz 1 2 3 4 5 6 7 8 Voltage (V) Frequency vs Voltage 4.5 4.55 4.6 4.65 4.7 4.75 p1 8 V 4.6796 GHz 4 V 4.6087 GHz 1 V 4.5525 GHz OSC_FREQ()[*,X] (GHz) CC PP Oscillator A p1: FREQ = 1 GHz 1e-006 1e-005 .0001 .001 Frequency (GHz) Phase Noise -140 -120 -100 -80 -60 -40 p2 p1 DB(PH_NOISE_F(PORT_1,1,1))[*,1] CC Oscillator A DB(PH_NOISE_F(PORT_1,2,1))[*,4] CC PP Oscillator A p1: FREQ = 1 GHz p2: FREQ = 1 GHz Vdc = 4 V X-Band Push-Push Oscillator Simulation and Measurement 7 www.cadence.com/go/awr

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