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ABSTRACT A fully CMOS integrated low TX noise UHF RFID digital transmitter with tunable directional coupler is proposed. The transmitter decreases the AM noise density to −144.6 dBc/Hz at 10 kHz offset by eliminating noisy conventional analog components and optimizing LO chain. The tunable transformer-based directional coupler which is feasible for CMOS integration exhibits high isolation performance of −55 dB over the entire band. The transmitter with quadrature DPA structure supports DSB/SSB/PR-ASK modulation, and with the directional coupler, it achieves 22.8 dBm peak power with drain efficiency of 37.8%. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1750-1756, 2016 [ABSTRACT FROM AUTHOR]

This article presents a 2-GHz fully-differential CMOS power amplifier (PA) fabricated in a standard 0.35-μm RF CMOS process. Virtual grounds are introduced at both drive-stage and output-stage transistors' sources of the two-stage differential PA, which guarantees a stable reference ground and thus improves the PA performance. A performance of 15-dB gain, 26.6 dBm Pout, and 26% PAE is achieved. At 15 dBm Pout, the ACPR1 and ACPR2 are -35.3 and -66.3 dBc, respectively. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2780–2784, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22849 [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a post-CMOS selective grown porous silicon (SGPS) technique is proposed to achieve high-performance integrated inductor and effective isolation. The inductors and isolation structures are fabricated in standard CMOS process and then this post-CMOS SGPS technique is carried out to greatly improve the performances of inductors and crosstalk isolation. For a 4.5nH inductor fabricated in standard CMOS process, an over 100% increase (from 4.8 to 9.7) in peak Q-factor and an about 200% increase (from 4GHz to 12GHz) in resonance frequency are obtained. Furthermore, a thick SGPS trench for crosstalk isolation has been formed and about 20dB improvement in substrate isolation is achieved. These results demonstrate that the post-CMOS SGPS technique is very promising for RFIC applications. [Copyright &y& Elsevier]

A fully integrated ultrawideband (UWB) bipolar cascode with metal oxide semiconductor field effect transistor (BiFET) mixer using standard commercial 0.35-μm silicon germanium bipolar complementary metal oxide semiconductor technology was first proposed and fabricated in this study. This presented BiFET mixer using bipolar junction transistor as the transconductor stage and metal oxide semiconductor field effect transistor as the switch stage to achieve noise power and linearity trade-off. This 3–5-GHz UWB mixer achieves a conversion gain of 4.5 ± 0.5 dB at the designed band. The mixer core draws a current of 2.5 mA from a supply voltage of 3 V, while consumes chip area of 0.9 × 0.9 mm2. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 965–968, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22305 [ABSTRACT FROM AUTHOR]

This letter proposes a miniature CMOS stacked spiral-coupled (SSC) directional coupler for a fully integrated CMOS transceiver to isolate the large transmit power from the transmitter to the receiver. It consists of two 90 ^\circ-rotated center-aligned SSC coils. The path center of one coil is aligned to the gap center of the other coil. The grounded secondary coil plays a role of ground shielding for reducing the insertion loss. Two capacitors are utilized for tuning the center frequency and isolation level. Fabricated in a standard CMOS process, it achieves an isolation of -67 dB, an insertion loss of -0.8 dB, and a coupling of -16.1 dB and only occupies \0.3 \times \0.3\ \mm^2 of silicon area. To the authors' knowledge, this is the first CMOS directional coupler at the UHF band, with the smallest form factor when compared with other implementations of directional couplers. [ABSTRACT FROM PUBLISHER]

Characteristics of symmetrical spiral inductor in differential mode is studied and optimized in this work. The characteristics of interest include inductor value, quality factor, peak frequency and self-resonance frequency. Both single-layer and double-layer inductor using top metals are characterized. Inductor excited in differential mode and single-ended mode are characterized for comparison. The optimized symmetrical spiral inductors are fabricated in standard digital 0.35 μm CMOS process. Experimental results show 60–100% improvement of quality factor and peak frequency, meanwhile 10–20% improvement of self-resonance frequency by exciting the symmetrical spiral inductors in differential mode compared with single-ended mode. To further validate the characterized inductor, the differential spiral inductors are adopted in optimizing low power and low phase noise fully integrated 2.4 GHz voltage-controlled oscillator (VCO). The designed VCO achieved phase noise of more than -105 dBc/Hz at 100 kHz offset with approximately 4.5 mA at 3.0 V supply. [Copyright &y& Elsevier]