A Fundamental 90-GHz CMOS VCO Using New Ring-Coupled Quad

Abstract

A new circuit topology, named ring-coupled quad for millimeter-wave voltage controlled oscillator (VCO) design, is proposed. The proposed circuit topology provides higher open loop voltage gain than conventional cross-coupled pair. The layout of the proposed ring-coupled quad is fully symmetric without additional interconnection lines. A 90-GHz VCO using 90-nm CMOS process is implemented with this ring-coupled quad. This 90-GHz oscillator demonstrates a 2.5-GHz tuning range and higher than 20 dBm output power. The proposed ring-coupled quad is suitable for the realization of high frequency VCOs.

Performance and Trends in Millimetre-Wave CMOS Oscillators for Emerging Wireless Applications

“…The FOM achieved by the state-of-the-art mm-wave CMOS LC-VCOs and ROs published in the last 11 years are shown in Figure 9. Also in this case, as in Figure 7 relative to PN, it can be noted that in the lower part of the mm-wave range (below 60 GHz) LC-VCOs attain overall better FOM 64 [18] 68 [16] 90 [24] 60 [17] [6]…”

“…Oscillator FOM versus oscillation frequency[6,7,[9][10][11][13][14][15][16][17][18][19][20][21][22][23][24].…”

Recent development of millimeter-wave CMOS monolithic integrated circuits

“…Another highlight of MMW VCO development is that a novel ring-coupled quad NMOS is proposed to design MMW VCO [28]. This ring-coupled quad can not only provide better loop gain than the conventional cross-coupled pair, but also eliminate the cross-over in the layout design.…”

An 80‐100 GHz VCO using auxiliary cross‐coupled pair and push‐push topology in 0.18‐μm CMOS

“…Therefore, there are many works to overcome the limitation f max of CMOS on conventional CMOS LC VCOs which can achieve high frequency. The common techniques of CMOS VCOs with fundamental mode up to W‐band have been reported . However, the frequency tuning range is still narrow, which does not exceed 3% of the highest frequency.…”

“…The common techniques of CMOS VCOs with fundamental mode up to W-band have been reported. 1,2 However, the frequency tuning range is still narrow, which does not exceed 3% of the highest frequency. Other approaches adopt the push-push topology to double the output frequencies, which are the second-order harmonic frequency accompanied by the fundamental frequency.…”