A low-noise amplifier, direct-conversion quadrature mixer, power amplifier, and voltage-controlled oscillators have been implemented in a 012-/spl mu/m, 200-GHz f/sub T/290-GHz f/sub MAX/ SiGe bipolar technology for operation at 60 GHz At 615 GHz, the two-stage LNA achieves 45-dB NF, 15-dB gain, consuming 6 mA from 18 V This is the first known demonstration of a silicon LNA at V-band The downconverter consists of a preamplifier, I/Q double-balanced mixers, a frequency tripler, and a quadrature generator, and is again the first known demonstration of silicon active mixers at V-band At 60 GHz, the downconverter gain is 186 dB and the NF is 133 dB, and the circuit consumes 55 mA from 27 V, while the output buffers consume an additional 52 mA The balanced class-AB PA provides 108-dB gain, +112-dBm 1-dB compression point, 43% maximum PAE, and 16-dBm saturated output power Finally, fully differential Colpitts VCOs have been implemented at 22 and 67 GHz The 67-GHz VCO has a phase noise better than -98 dBc/Hz at 1-MHz offset, and provides a 31% tuning range for 8-mA current consumption from a 3-V supply

SiGe bipolar transceiver circuits operating at 60 GHz

The unlicensed band around 60 GHz can be utilized for wireless communications at data rates of several gigabits per second. This paper describes a receiver front-end that incorporates a folded microstrip geometry to create resonance at 60 GHz in a common-gate LNA and active mixers. Realized in 0.13-/spl mu/m CMOS technology, the receiver front-end provides a voltage gain of 28 dB with a noise figure of 12.5 dB while consuming 9 mW from a 1.2-V supply.

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A 60-GHz CMOS receiver front-end

A radar system with an ultra-wide FMCW ramp bandwidth of 25.6 GHz (≈32%) around a center frequency of 80 GHz is presented. The system is based on a monostatic fully integrated SiGe transceiver chip, which is stabilized using conventional fractional-N PLL chips at a reference frequency of 100 MHz. The achieved in-loop phase noise is ≈ -88 dBc/Hz (10 kHz offset frequency) for the center frequency and below ≈-80 dBc/Hz in the wide frequency band of 25.6 GHz for all offset frequencies >;1 kHz. The ultra-wide PLL-stabilization was achieved using a reverse frequency position mixer in the PLL (offset-PLL) resulting in a compensation of the variation of the oscillators tuning sensitivity with the variation of the N-divider in the PLL. The output power of the transceiver chip, as well as of the mm-wave module (containing a waveguide transition), is sufficiently flat versus the output frequency (variation <;3 dB). In radar measurements using the full bandwidth an ultra-high spatial resolution of 7.12 mm was achieved. The standard deviation between repeated measurements of the same target is 0.36 μm.

An Ultra-Wideband 80 GHz FMCW Radar System Using a SiGe Bipolar Transceiver Chip Stabilized by a Fractional-N PLL Synthesizer

Silicon planar and three-dimensional inductors and transformers were designed and characterized on-wafer up to 100 GHz. Self-resonance frequencies (SRFs) beyond 100 GHz were obtained, demonstrating for the first time that spiral structures are suitable for applications such as 60-GHz wireless local area network and 77-GHz automotive RADAR. Minimizing area over substrate is critical to achieving high SRF. A stacked transformer is reported with S/sub 21/ of -2.5 dB at 50 GHz, and which offers improved performance and less area (30 /spl mu/m/spl times/30 /spl mu/m) than planar transformers or microstrip couplers. A compact inductor model is described, along with a methodology for extracting model parameters from simulated or measured y-parameters. Millimeter-wave SiGe BiCMOS mixer and voltage-controlled-oscillator circuits employing spiral inductors are presented with better or comparable performance to previously reported transmission-line-based circuits.

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30-100-GHz inductors and transformers for millimeter-wave (Bi)CMOS integrated circuits

This paper describes the design of CMOS millimeter-wave voltage controlled oscillators. Varactor, transistor, and inductor designs are optimized to reduce the parasitic capacitances. An investigation of tradeoff between quality factor and tuning range for MOS varactors at 24 GHz has shown that the polysilicon gate lengths between 0.18 and 0.24 /spl mu/m result both good quality factor (>12) and C/sub max//C/sub min/ ratio (/spl sim/3) in the 0.13-/spl mu/m CMOS process used for the study. The components were utilized to realize a VCO operating around 60 GHz with a tuning range of 5.8 GHz. A 99-GHz VCO with a tuning range of 2.5 GHz, phase noise of -102.7 dBc/Hz at 10-MHz offset and power consumption of 7-15mW from a 1.5-V supply and a 105-GHz VCO are also demonstrated. This is the CMOS circuit with the highest fundamental operating frequency. The lumped element approach can be used even for VCOs operating near 100-GHz and it results a smaller circuit area.

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Millimeter-wave voltage-controlled oscillators in 0.13-/spl mu/m CMOS technology

It is demonstrated that SiGe bipolar technologies are well suited for voltage-controlled oscillators (VCOs) in 77-GHz automotive radar systems. For this, the design of a VCO with powerful output buffer (with good decoupling capability and high output power), comparatively wide tuning range, and reasonably low phase noise is described. To achieve the required high output power, the potential operating range of the output transistors, limited by high-current effects and avalanche breakdown, respectively, had to be exploited using adequate transistor models. The VCOs need a single supply voltage only and have been fully integrated (including resonant circuit and output buffer) on a single small (1 mm/sup 2/) chip, demonstrating their low-cost potential. Experimental results showed, at a center frequency of around 77 GHz, a usable tuning range of 6.7 GHz and a phase noise of -97 dBc/Hz at 1-MHz offset frequency averaged over this range. In addition, the center oscillation frequency can be coarsely adjusted within a wide range by cutting links in the upper metallization layer. The total signal power delivered by both buffer outputs together is as high as 18.5 dBm at a power consumption of 1.2 W. Simulations let us expect a potential doubling of the output power (for two or four outputs) by extension of the output buffer. To get an impression of the maximum frequency achievable with the circuit concept and technology used, a second VCO (again with buffered output) has been developed. To the best of the authors' knowledge, the measured maximum oscillation frequency of about 100 GHz, at 12.4-dBm total output power (14.3 dBm at 99 GHz), is a record value for SiGe VCOs with buffered output operating at their fundamental frequency. The usable tuning range is still 6.2 GHz.

Fully integrated SiGe VCOs with powerful output buffer for 77-GHz automotive Radar systems and applications around 100 GHz

Millimeter-wave voltage-controlled oscillators (VCOs) are presented which are fully integrated in a SiGe bipolar production technology. The low-cost differential circuits have been designed and optimized for low phase noise and wide tuning range. As an example, by varying the bias voltage of the on-chip varactor, the oscillation frequency can be changed from 36 to 46.9 GHz (i.e., by 26%). In this wide frequency range, phase noise between -107 and -110dBc/Hz at 1-MHz offset frequency and single-ended voltage swing of about 0.95V/sub pp/ /spl plusmn/10% (differential: 1.9V/sub pp/) were measured. The circuit consumes 280mW at -5.5-V supply voltage. The high oscillation frequency and low phase noise at wide tuning range are record values for fully integrated oscillators in Si-based technologies. The basic oscillator was then extended by a cascode stage as an output buffer. Now the VCO performance is no longer degraded if nonperfectly terminated transmission lines are driven. Thus, the chip can be mounted in a low-cost socket; however, at the cost of increased phase noise and power consumption.

Millimeter-wave VCOs with wide tuning range and low phase noise, fully integrated in a SiGe bipolar production technology

It is demonstrated that SiGe bipolar preproduction technologies are well suited for VCOs in 77 GHz automotive radar systems. Due to the relatively high output power aimed at, the designer has to consider the physical transistor limits carefully. The VCOs need a single supply voltage only and have been fully integrated (including resonant circuit and output buffer) on a single small (1 mm/sup 2/) chip, demonstrating their low-cost potential. First experimental results based on a not fully optimized design showed at a center frequency of about 77 GHz, a tuning range of 4.3 GHz, and a phase noise of -95 dBc/Hz at 1 MHz offset frequency. The total signal power of both outputs is 14.3 dBm. Simulations demonstrate a further potential increase of total output power (for two or four outputs) by about 5 dBm.

Hao Li

Papers

Fully integrated SiGe VCOs with powerful output buffer for 77-GHz automotive Radar systems and applications around 100 GHz

Millimeter-wave VCOs with wide tuning range and low phase noise, fully integrated in a SiGe bipolar production technology

Design of W-band VCOs with high output power for potential application in 77 GHz automotive radar systems