A Quadrature Generator-Splitter and Vector Modulator Adders for a 5.8-GHz FMCW Phased Array Transmitter in 65nm CMOS

Abstract

This paper presents a quadrature generator network and vector modulator adders for a 4-channel phased array for a frequency-modulated-continues-wave (FMCW) transmitter in the 5.8 GHz frequency band. The study employed the quadrature generator as a 4-way splitter to split the generated FMCW signal into transmitter channels. The phase of each channel is controlled by a 6-bit active vector modulator that enables 360° coverage with a phased resolution of 22.5° followed by VGA driver and PA. The addition of utilizing active loads with feedback resistors enabled inductor-less design and cost effective array integration in this frequency band. The TX quadrature generator splitter network and 4-channel vector modulators unit is implemented with the size of $0.25\text{mm}\times 1.5\text{mm}$ in 65 nm CMOS technology. The simulated and measured phase RMS error less than 2° and 5° has been achieved, respectively as well as simulated and measured RMS gain error of less than 0.2 dB and 0.6 dB. The power consumption of the entire unit is 23 mW from a 1 V supply.