Design of 2.4 GHz CMOS LC Oscillator for RF Front End Direct Conversion Receiver

Oscillators are the vital part of RF communication system. The Local Oscillator (LO) signal is required for carrier frequency synthesis to up-convert, down convert, or image reject the signal as required. There are two important criteria to achieve desire performance for a LO in communication system, that is, low phase error and acceptable amplitude. This paper reviews the LC oscillator with oscillation frequency 2.4 GHz designed for low phase noise and low power consumption. The oscillator design is based on differential structure where NMOS & PMOS transistors are cross-coupled. The inductor-capacitor (LC) tank uses varactors for compensating the disturbances in the center oscillating frequency. Certain applications are there which work on 2.4 GHz oscillation frequency like Bluetooth, WLAN, Zigbee, Wi-Fi. The circuit is designed using 180 nm CMOS technology. The operating supply voltage of oscillator is 1.8 V and power dissipation in the circuit is around 1.22 mW. After simulation, the designed oscillator exhibits a phase noise of −130.27 dBc/Hz at 1 MHz offset frequency.