Bluetooth transmitter design for IOT nodes

Abstract

the recent year, there has been a marked growth in technologies such as Bluetooth and 802.11b (Wi-Fi) have increased the growth of the short-range communication industry. Bluetooth, the leading WPAN (wireless personal area network) technology, was designed primarily to reduce the cable applications. Bluetooth operates internationally in unlicensed ISM frequency band i.e. 2.4GHz due unlicensed ISM band, it is very popular in short-range wireless communication and support a wider range of applications. In this thesis, Bluetooth transmitter has been discussed and implemented using a mixed signal technology in low cost for IoT nodes. Bluetooth transmitter architecture include GFSK (Gaussian frequency shift keying) modulation scheme which fully in digital domain and remaining stage like digital to analog convertor, Op-Amp based low pass filter, up-conversion mixer and class E power amplifier are designed in 180nm CMOS technology. In this thesis, partially discussed about GFSK (Gaussian frequency shift keying) modulation scheme and DAC and mainly focus on Op-Amp based low pass filter, up-conversion mixer and power amplifier. Op-Amp based low pass filter are designed to remove the glitches which are occur at digital to analog convertor (DAC) due fast switching. Gilbert cell based up-conversion mixer is designed to translate the incoming frequencies from the modulator to desired ISM band i.e. 2.4 to 2.485 GHz. In the thesis, there are two mixer circuit has been implemented i.e. conventional Gilbert up-conversion mixer and current controlled up-conversion mixer, where conversion gain is around 13dB at 5dB LO power. Class E power amplifier circuit for 50Ω load is implemented to provide additional gain to send the signal from the RF antenna.