FM-UWB transmitter using RC oscillators

This work describes the implementation of an FM-UWB transmitter in a standard 0.13 μm CMOS technology. An FM-UWB transmitter requires both a tuneable triangular wave and a tuneable sinusoidal wave. The circuit topology proposed in this paper uses two inductorless relaxation oscillators which provide huge area savings. One of the oscillators is used for the FSK modulator by generating a triangular signal with two different periods, controlled by the transmitted data. The other oscillator, used to produce the carrier signal, is a VCO capable of achieving 1 GHz of tuning range bandwidth with an operation frequency around 8 GHz. Simulation results of the complete transmitter, considering pads, ESD and an antenna with 50 Ω @8.3_GHz are presented. The circuit output respects the UWB mask on the universal sub-band of 7.25-8.5 GHz. The transmitter has a power consumption of 9.7 mW and an active area of 0.071 mm².