of WLAN applications. A parametric study is implemented to investigate the characteristic of the proposed antenna. Two dominant parameters that determine the antenna's performance are discussed, and the simulated curves are given. The antenna not only has good impedance matching properties, but also the advantages of simple structure, small size, and low cost. All results demonstrate that the proposed antenna is of great use for WLAN applications. REFERENCES 1. J. Janapsatya, K.P. Esselle, and T.S. Bird, A dual-band and wideband planar inverted-F antenna for WLAN applications, Microwave Opt Technol Lett 50 (2008), 138-141. 2. D.-U. Sim and J.-Jck Choi, A compact wideband modified planar inverted F antenna (PIFA) for 2.4/5-GHz WLAN applications, IEEE Antennas Wirel Propag Lett 5 (2006), 391-394. 3. X.L. Bao and M.J. Ammann, Microstrip-fed dual-frequency annular-slot antenna loaded by split-ring-slot, IET Microwaves Antennas Propag 3 (2009), 757-764. 4. C.-M. Wu, Dual-band CPW-fed cross-slot monopole antenna forABSTRACT: This article present a development of low phase noise 14bit digitally controlled oscillator (DCO) based on ring oscillator with quadrature output in 0.18-lm CMOS technology. Proposed design use digital control and feed-forward technique to obtain wider output swing and stable quadrature output on even number of stages respectively. Designed DCO has tuning frequency range from 212 MHz to 1 GHz. Phase noise at 1-MHz frequency offset is À123.93 dBc/Hz, which is the lowest among the recently published result.