Integrated chip design of a 10GHz band voltage controlled oscillator and charge-injected mixer with low phase noise and wide tuning range

A simple low phase noise and wide tuning range voltage-controlled oscillator (VCO) is designed for 10 GHz band application. The proposed oscillator adopts a complementary cross-coupled pair LC-VCO circuit with only one symmetrical inductor and implemented in TSMC 0.18-um CMOS process. A 10 GHz broadband CMOS double-balance mixer for communication receiver is presented. The broadband mixer is fabricated with low power 0.18 μm standard CMOS process. Measurement of the integrated mixer is performed as chipset input return loss is higher than 8.5 dB. At the supply voltage of 1.8 V, measured results achieve a tuning range of 9.6 to 11.08 GHz, corresponding to 13.9 %, a phase noise under -115.1 dBc/Hz at a 1 MHz offset frequency from 10.02 GHz with a tuned control voltage from 0 to 1.7 V and an output power of -2.231 dBm at 50-Ω termination and at 10.02 GHz. The power consumption is 3.58 mW and the chip area including pads is 0.61×0.66 (0.37) mm². The proposed VCO, without the need of any off-chip device, is well suitable for mobile cellular networks applications.

I. Introduction

Requirements of low phase noise, wide tuning range and low cost integrated chip become an important issue. Fully integrated LC-VCO is one of the most important and challenging building blocks in a RF transceiver. With the demand for low phase noise, wide tuning range and low cost, on-chip VCO with no off-chip devices is the best choice. However, the low Q on-chip passive component such as inductor will degrade the VCO phase noise performance. Oscillators can be implemented in several ways, including ring, transformer coupling, and LC VCO etc. Ring VCO circuits don't need L or C components in order to save chip area, but they generate more phase noise, lower operation frequency and higher power dissipation. The transformer coupling VCO circuits accomplish low phase noise performance, but they operate in lower frequency and narrower tuning range [1]–[3]. LCtank oscillators, in comparison to ring oscillators, have rather limited tuning range and feature lower phase noise at lower power consumption, but the chip area is much bigger with integrated coil, but for high frequency up to 10 GHz, coil area is no longer important as the coil size decreases with higher frequencies. Comparing to the transformer-coupled base VCO circuits, LCtank oscillators yield a wide tuning range. Recently, a low voltage VCO, as low as 0.4 V, was published and attractive, but its tuning range is narrow only of 6.4% [4]. Hence, after considering those factors of tuning range, phase noise, operation frequency, power consumption, and chip area, a complementary cross-coupled LC-VCO is proposed and fabricated with TSMC CMOS process. This proposed VCO has the advantages of using a complementary cross-coupled LC-tank architecture, no off-chip devices and push-pull buffers. The simplicity of the circuit that allows the generation of a differential negative resistance with only two MOS transistors in the signal path makes the circuit very attractive for application where low phase noise with wide tuning range and low power consumption at 10 GHz band become key performance indices.