In this paper, we present a low cost RF oscillator design incorporating a folded parallel coupled resonator. The oscillator is designed on FR4 substrate to achieve low cost. FR4 is a low cost substrate but has a poorly controlled dielectric constant and high loss tangent thereby challenging the design of higher performance circuits. This oscillator operates in 900 MHz band, delivers an output of -3.13 dBm and has phase noise 101.8 dBc/Hz at 10 kHz offset. The size of the folded parallel coupled resonator is 16% smaller than the conventional parallel coupled resonator, thereby making the overall circuit more compact. The power output and phase noise results are better than the oscillator designed with conventional resonator. Open loop analysis method has been adopted for the oscillator design and analysis. The measured data shows good agreement with the simulated results. The performance parameters of this oscillator make it suitable for use in low cost wireless communication solutions in 900 MHz band.
2. Razavi, B., "Challenges in portable RF transceiver design," IEEE Circuits and Devices Magazine, Vol. 12, No. 5, 12-25, September 1996.
3. Leeson, D. B., "A simplfied model of feedback oscillator noise spectrum," Proceedings of IEEE, Vol. 42, 329-330, February 1965.
4. Rhea, R. W., "Designing a low noise VCO on FR4," RF Design, 72-77, September 1999.
5. Robinson, J. M., "SAW coupled resonator oscillator technology," RF Monolithics, INC., www.rfm.com/support/appnotes/.
6. Podcameni, A. and L. F. M. Conrado, "Design of microwave oscillator and filters using transmission-mode dielectric resonators coupled to microstrip lines ," IEEE Transactions on Microwave Theory and Techniques, Vol. 33, 1329-1332, December 1985.
7. Kikkert, C. J., "Dual coupled resonator local oscillator," Paper 1568965076, TENCON, 2005, 2005.
8. Makimoto, M. and S. Yamashita, Microwave Resonators and Filters for Wireless Communications, Springer-Verlag, Berlin Heidelberg, New York, 2000.
9. Chen, J. L., S. F. Chang, and S. W. Kuo, "A low phase-noise oscillator with a planar capacitively loaded microstrip resonator," IEEE Proceedings of APMC 2001, Vol. 3, 1092-1095, 2001.
10. Toledo, N. G., "Practical techniques for designing microstrip tapped hairpin resonator filters on FR4 laminates,", available: www.wireless.asti.dost.gov.ph/sitebody/techpapers/hairpin pej.-DOC.
11. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001.
12. Rhea, R. W., "High-Q resonators on FR4," Applied Microwave & Wireless, 64-66, 1999.
13. Jones, E. M. T. and J. T. Bolljahn, "Coupled-strip transmission line filters and directional couplers," IRE Transactions on Microwave Theory and Techniques, Vol. 4, No. 4, 75-81, April 1956.
14. Matthaei, G. L., "Interdigital band-pass filters," IEEE Transactions on Microwave Theory and Techniques, Vol. 10, 479-491, November 1962.
15. Dishal, M., "A simple design procedure for small percentage bandwidth round rod interdigital filters," IRE Transactions on Microwave Theory and Techniques, 696-698, September 1965.
16. Caspi, S. and J. Adelman, "Design of combline and interdigital filters with tapped-line input," IEEE Transactions on Microwave Theory and Tecniques, Vol. 36, 759-763, April 1998.
17. Wong, J. S., "Microstrip tapped line filter design," IEEE Transactions on Microwave Theory and Techniques, Vol. 27, No. 1, 44-50, January 1979.
18. Pozar, D. M., Microwave Engineering, 2 Ed., Wiley, New York, 1998.
19. Park, E. and C. Seo, "Low phase noise oscillator using microstrip square open loop resonator," IEEE MTT-S International Microwave Symposium Digest, 585-588, June 2006.
20. Rhea, R. W., Oscillator Design and Computer Simulation, Noble, 1995.
21. Rhea, R. W., "Designing a low noise VCO on FR4,", www.rfdesign.com, September 1999.