Millimeter Wave CMOS Circuit Design

We have developed a 27- and 40-GHz tuned ampli- fier and a 52.5-GHz voltage-controlled oscillator using 0.18- m CMOS. The line-reflect-line calibrations with a microstrip-line structure, consisting of metal1 and metal6, was quite effective to extract the accurate -parameters for the intrinsic transistor on an Si substrate and realized the precise design. Using this technique, we obtained a 17-dB gain and 14-dBm output power at 27 GHz for the tuned amplifier. We also obtained a 7-dB gain and a 10.4-dBm output power with a good input and output return loss at 40 GHz. Additionally, we obtained an oscillation frequency of 52.5 GHz with phase noise of 86 dBc/Hz at a 1-MHz offset. These results indicate that our proposed technique is suitable for CMOS millimeter-wave design.

THE RAPID growth of wireless communication using, for example, mobile phones and wireless local area networks (LANs), has created a great demand for Si-based RF integrated circuits (RFICs), operating at microwave and millimeter-wave bands. These applications require a low production cost, thus, CMOS is the most attractive solution and the best component. However, the CMOS maximum oscillation frequency , an important parameter for analog circuits, is no higher than those of other devices, such as SiGe HBT and III–V devices. Therefore, it has been difficult to realize analog circuits, especially tuned amplifiers, which operate at close to millimeter-wave frequencies. The III–V devices have accurate parameters around these frequencies because they are fabricated on semi-insulating substrates, and it is easy to eliminate the parasitic parameters. However, CMOS has to be fabricated on a conductive substrate, and its parameters are not applicable to this frequency range. Amplifiers based on III–V and SiGe technologies have been reported. However, there have been very few reports about CMOS amplifiers [1]. In this paper, we propose an accurate parameter-extraction technique with a line-reflect-line (LRL) calibration for CMOS technology, and report a 27- and 40-GHz tuned amplifier and a 52.5-GHz voltage-controlled oscillator (VCO). This parameter-extraction technique provides us with accurate -parameters of the intrinsic transistor and enables the precise design of the integrated circuits. The extraction of accurate parameters for transistors and transmission lines is important for millimeter-wave circuit design. To achieve this, we used a microstrip-line (MSL) structure, which consists of a metal1 ground and a metal6 signal line . This line structure eliminates the effect of the conductive substrate and provides us with accurate characteristic impedance, allowing us to avoid unwanted differences between the simulation and measured values. The MSL characteristics, obtained through electric–magnetic (EM) simulation, agreed well with the measured results, even though our metal1 had slots to relax the stress. This enabled us to design the matching circuits more precisely. We prepared the parameter-extraction pattern for the transistor,

Free download research paper