The Design Of Voltage Controlled Oscillator And High-speed Divider For WLAN 802.11b Application

The voltage-controlled oscillator(VCO)is the core module that generates local oscillator signal in wireless communication system.It cooperates with the high-speed frequency divider circuit to generate orthogonal differential signals.In wireless local area network(WLAN)applications,802.11 b has the advantages of avoiding network conflicts and greatly improving network efficiency.Therefore,the voltage-controlled oscillator and high-speed divider designed for WLAN 802.11 b in this paper have a good engineering background and application value.The orthogonal VCO designed in this article is based on the 40 nm RF CMOS process,the operating frequency band covering 2.4?2.5GHz.The orthogonal VCO is composed of a VCO and a high-speed frequency divider.The VCO operating frequency band covers 4.8?5.0GHz.After the high-speed frequency divider divides the frequency,the operating frequency band covers2.4?2.5GHz,while generating orthogonal differential signals.In order to meet the low power consumption requirements of wearable devices,the voltage-controlled oscillator uses a complementary cross-coupling LC-VCO structure to improve power consumption through current multiplexing technology.In the design of the high-speed frequency circuit,in order to reduce power consumption and reduce the quadrature error,the design uses tail current injection type injection locked frequency divider(ILFD)to divide the output signal of the oscillator by two and generate quadrature signal.In order to meet the requirements of low tuning gain and wide tuning range,Both VCO and ILFD use a four-bit binary switched capacitor array,this structure uses segmented tuning to achieve low tuning gain,while achieving a wide tuning range to overcome the frequency deviation caused by different process angles.The post-simulation results under the Cadence Spectre environment show that under 1.1V supply voltage,the power consumption of the VCO is less than 2.98 m A,the operating frequency range is 4.72 ? 5.24 GHz,the tuning gain is less than 249.88MHz/V,the phase noise is less than-115.31 d Bc/Hz@1MHz.The power consumption of ILFD is less than 2.57 m A,the division range is 4.72 ? 5.24 GHz.The layout area of the cascade circuit formed by VCO and ILFD is about 1.31mm2.The performance of the circuit based on the 40 nm RF CMOS process designed in this subject meets the design index requirements,and can be applied to the phase-locked loop of the wireless communication system after tape-out verification.The performance of the circuit based on the40 nm RF CMOS process designed in this subject meets the design index requirements,and can be applied to the phase-locked loop of the wireless communication system after tape-out verification.