Description

In this paper, a new method of designing RF ring oscillator using current-mode technology is presented. The current-mode low frequency oscillator theory is transferred to facilitate the design of RF ring oscillator. As an example, a current-mode RF quadrature ring oscillator (RFQRO) for L-band wireless communication applications is presented. The current-mode RFQRO consists of two firstorder all-pass filters, and it provides four quadrature RF sinusoidal outputs. The proposed current-mode RFQRO is verified with GlobalFoundries’ 0.18 µm 1P6M CMOS RF process. The simulated and measured results demonstrate that the proposed RFQRO works at 1.03 GHz, and its frequency tuning range is from 648.9 MHz to 1.17 GHz by adjusting the bias voltage from 0.62 to 1 V. The measured phase noise of the RFQRO is −105.5 dBc/Hz at 1 MHz offset, and it consumes 2.5 mW from 1 V supply voltage.