Extremely low thermal noise floor, high power oscillators usingsurface transverse wave devices

摘要

This paper presents state-of-the-art results on 1-GHz surfacentransverse wave (STW) oscillators running at extremely high loop powernlevels. The high-Q single-mode STW resonators used in these designs havenan insertion loss of 3.6 dB, an unloaded Q of 8000, a residual PM noisenof -142 dBc/Hz at a 1-Hz carrier offset, and operate at an incidentnpower of up to +31 dBm in the loop. Other low-Q STW resonators andncoupled resonator filters (CRF), with insertion losses in the 5-9 dBnrange, can conveniently handle power levels in excess of two Watts.nThese devices were incorporated into voltage controlled oscillatorsn(VCO's) running from a 9.6-V dc source and provide an RF output power ofn+23 dBm at an RF/dc efficiency of 28%. Their tuning range was 750 kHznand the PM noise floor was -180 dBc/Hz. The oscillators, stabilized withnthe high-Q devices and using specially designed AB-class powernamplifiers, delivered an output power of +29 dBm and exhibited a PMnnoise floor of -184 dBc/Hz and a 1-Hz phase noise level of -17 dBc/Hz.nThe 1-Hz phase noise level was improved to -33 dBc/Hz using ancommercially available loop amplifier. In this case, the output powernwas +22 dBm. In all cases studied, the loop amplifier was found to benthe factor limiting the close-to-carrier oscillator phase noisenperformance