Synthesis of Electronic Frequency Tuning Units for Narrowband Ultra-Low Noise Oscillators with Surface Acoustic Waves Resonators

Introduction. Modern radio engineering systems impose strict requirements on the stability of the frequency of microwave oscillation sources (microwave generators) included in their composition. However, microwave oscillators (on dielectric resonators or resonators on surface acoustic waves), despite the low levels of power spectral density of frequency fluctuations of the generated signals, fail to exhibit the frequency stability required for most precision applications (phase noise meters, aircraft radars, ultra-low-noise frequency synthesizers). It is possible to increase the frequency stability of such oscillators, e.g., by using of a phase-locked loop system; however, for its implementation, as a rule, an electronic frequency tuning unit should be included in the microwave oscillator. The introduction of such a unit into the microwave oscillator can lead to degradation of its other electrical characteristics, e.g., the power spectral density of frequency fluctuations of the generated signals.

Aim. Development of a method for synthesizing electronic frequency tuning blocks with the required range of introduced phase shift and minimal intrinsic power loss for narrow-band microwave oscillators with resonators based on surface acoustic waves.

Materials and methods. The synthesis of electronic frequency tuning blocks is carried out by a numerical-analytical method using the MATLAB (academic license no. 906991) environment. The obtained results are analyzed by a comparative method.

Results. The paper presents a methodology for synthesizing electronic frequency tuning blocks with the required range of changes in the introduced phase shift while maintaining minimal insertion losses, which makes it possible to consider the intrinsic parasitic parameters of the varactor. Recommendations on the correct choice of varactors are given. A comparative analysis of calculated and practical results is carried out. The electronic frequency tuning unit was implemented on the basis of "Radiocomp" in 2023.

Conclusion. The presented methodology for synthesizing electronic frequency tuning blocks is versatile and can be used not only for the synthesis of electronic frequency tuning blocks of various narrow-band microwave oscillators using twoport resonators as a frequency-setting element, but also for the synthesis of narrow-band microwave phase shifters. 

1. Loiko V. A., Dobrovolsky A. A., Kochemasov V. N., Safin A. R. Self-Oscillators Based on Surface Acoustic Waves (A Review). Journal of the Russian Universities. Radioelectronics. 2022, vol. 25, no. 3, pp. 6–21. doi: 10.32603/1993-8985-2022-25-3-6-21

2. Tatopoulos X. Compact Ultra-low Noise SAW Oscillator with Reduced G-Sensitivity for Radar Applications. Intern. Radar Conf. Lille, France, 13–17 Oct. 2014. Piscataway, IEEE, 2014, pp. 1–3. doi: 10.1109/RADAR.2014.7060383

3. Everard J. A Review of Low Noise Oscillator. Theory and Design. Proc. of Intern. Frequency Control Symp. Piscataway, IEEE, 1997, pp. 909–918. doi: 10.1109/FREQ.1997.639208

4. Driscoll M. Low Noise, Microwave Signal Generation Using Bulk and Surface Acoustic Wave Resonators. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. 1988, vol. 35, no. 3, pp. 426– 434. doi: 10.1109/FREQ.1988.27627

5. Parker T. E., Montress G. K. Precision SurfaceAcoustic-Wave (SAW) Oscillators. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. 1988, vol. 35, no. 3, pp. 342–364. doi: 10.1109/58.204555

6. Parker T. E., Andres D. K. Designing Smaller SAW Oscillators for Low Vibration Sensitivity. Proc. of IEEE 48th Annual Symp. on Frequency Control. Boston, MA, USA, June 1994. IEEE, 1994, pp. 352–358. doi: 10.1109/FREQ.1994.398312

7. Bipin Kumar Das, Prakash Kumar. Tailoring of Specifications for Random Vibration Testing of Military Airborne Equipment’s from Measurement. IJRET: Intern. J. of Research in Engineering and Technology. 2015, vol. 4, iss. 12, pp. 293–299.

8. Leeson D. B. A Simple Model of Feedback Oscillator Noise Spectrum. IEEE Proc. 1966, vol. 54, no. 2, pp. 329–332. doi: 10.1109/PROC.1966.4682

9. Parzen B. Clarification and a Generalized Restatement of Leeson’s Oscillator Noise Model. Proc. of the 42nd Annual Frequency Control Symp., Baltimore, USA, 01–03 June 1988. IEEE, 1998, pp. 348–351. doi: 10.1109/FREQ.1988.27623

10. Quendo C., Rius E., Person C. Narrow Bandpass Filters Using Dual-Behavior Resonators Based on Stepped-Impedance Stubs and Different Length Stubs. IEEE Transactions on Microwave Theory and Techniques. 2004, vol. 52, iss. 3, pp. 1034–1044. doi: 10.1109/TMTT.2004.823582

11. Samuilov A. A., Cherkashin M. V., Babak L. I. "Visual" Design Technique for Networks on Lumped Elements Providing Broadband Matching of Two Complex Impedances. Reports of the Tomsk State University of Control Systems and Radioelectronics. 2013, no. 2(28), pp. 30–39.

12. Montress G. K., Parker T. E., Andres D. Review of SAW Oscillator Performance. Proc. of IEEE Ultrasonics Symp. 1994, vol. 1, pp. 43–54. doi: 10.1109/ULTSYM.1994.401550

13. Chomiki M. SAW Oscillators Fly on Airborne Radars. Microwaves and RF. 2010, vol. 49, no. 6, pp. 23–25.

14. Marini A. V., Ramaccia D., Toscano A., Bilotti F. Perfect Matching of Reactive Loads Through Complex Frequencies: from Circuital Analysis to Experiments. IEEE Transactions on Antennas and Propagation. 2022, vol. 70, iss. 10, pp. 9641–9651. doi: 10.1109/TAP.2022.3177571

15. Galantai A. The Theory of Newton’s Method. J. of Computational and Applied Mathematics. 2000, vol. 125, pp. 25–44. doi: 10.1016/S0377-0427(00)00435-0

16. Malyshev V. M., Matveev Yu. A., Nikitin A. B., Khudyakov A. V. Varactor Diode Model Used to Design Wideband Microwave Voltage-Controlled Oscillators. Scientific and Technical Bull. of St Petersburg Polytechnic University J. Physics and Mathematics. 2014, no. 2 (193), pp. 55–60.

17. Skyworks Solutions, Inc. Available at: https://www.skyworksinc.com/-/media/SkyWorks/Documents/Products/101-200/SMV1405_1430_Series_200068W.pdf (accessed 10.05.2023)