LC-tank oscillators in the 5∼6 GHz frequency range have been designed and implemented in a commercial 0.6 μm GaAs MESFET technology. One is a voltage-controlled oscillator (VCO), and the other is an oscillator without a controlling element. The output frequency range of the VCO is from 5.44 to 6.14 GHz, and the measured phase-noise is -101.67 dBc/Hz at an offset frequency of 600 KHz from the 5.44 GHz carrier. The phase-noise of the 6.44 GHz oscillator is - 108 dBc/Hz at an offset frequency of 600 KHz, and the phase-noise curve, in the offset frequency range between 100 KHz and 1 MHz, shows a - 20 dB/decade slope. These phase-noise characteristics are comparable to, or better than, those of the reported 5∼6 GHz-band CMOS oscillators. To our knowledge, this is the first GaAs MESFET-based oscillator which has a cross-coupled differential topology and a capacitive coupling feedback to suppress the up-conversion of 1/f noise. Also, it is first reported that the GaAs MESFET-based oscillator shows 1/f 2 phase-noise behavior across the offset frequency range from 100 KHz to 1 MHz.
Bibliographical noteFunding Information:
Manuscript received June 29, 2001; revised October 19, 2001. The fabrication of the MMIC using the TRIQUINT GaAs foundry was supported by TELTRON, Taejon, Korea. The review of this letter was arranged by Associate Editor Dr. Arvind Sharma.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Electrical and Electronic Engineering