Dual Band VCO Based on a High-Quality Factor Switched Interdigital Resonator for the Ku Band Using 180-nm CMOS Technology

A dual band and low phase noise Ku-band voltage-controlled oscillator (VCO) using 180-nm CMOS technology is presented in this brief. The proposed VCO employs a switched notch filter that can operate in the low and high band, which depends on the state of nmos transistor and has a quality factor that is higher than that of a conventional inductor-capacitor (LC) resonator. The proposed resonator doubles the quality factor compared to LC in the technology and reduces the total die area. The first band is realized by the switched interdigital resonator when a nMOS transistor is in the off state. Furthermore, the second band is realized by turning nmos transistor to the on state, which is located between two fingers in the proposed resonator. The chip is implemented in 180-nm CMOS technology, and found that the proposed VCO operates from 15.5 to 16.7 Hz (low band) and 16.6 to 17.4 GHz (high band). At 1.8-V power supply, the power consumption of the oscillator core is 5.4 and 7.2 mW in the low- and high-frequency bands, respectively. The measured phase noise is -107 dBc/Hz at 1 MHz offset from 16.7-GHz carrier frequency.