This paper reports on an optimal support anchoring for bar-type BAW resonators. We demonstrate both theoretically and experimentally the implementation of long (in terms of acoustic wavelength) T-supports without compromising neither on the Q-factor nor on the electromechanical (pull-in) stability of the resonator. Compared to the more common straight supports, these long T-supports provide rigidity for displacements in one direction combined with low stiffness in the other two directions, thus offering more freedom in the structural design, as well as potential for thermal "manipulation", e.g., insulation.

MEMS based timing devices have been proposed as an alternative to Quartz systems for certain applications. Through using an oven-controlled system it is possible to stabilize the frequency response of such a MEMS system over a large ambient temperature range. This work presents a BAW MEMS resonator in poly-SiGe which achieves significantly lower power consumption for frequency stabilization over temperature through Joule heating than for a similar system in SOI, while showing promising phase noise performance in an oscillator setup. Since the poly-SiGe resonator can be processed on top of standard CMOS, this enables the possibility of full integration of an Oven-Controlled MEMS Oscillator.

Substrate noise generated by the switching digital circuits degrades the performance of analog circuits embedded on the same substrate. It is therefore important to know the amount of noise at a certain point on the substrate. Existing transistor-level simulation approaches based on a substrate model extracted from layout information are not feasible for digital circuits of practical size. This paper presents a complete high-level methodology, which simulates a large digital standard cell-based design using a network of substrate macromodels, with one macromodel for each standard cell. Such macromodels can be constructed for both EPI-type and bulk-type substrates. Comparison of our substrate waveform analysis (SWAN) to several measurements and to several full SPICE simulations indicates that the substrate noise is simulated with our methodology within 10%-20% error in the time domain and within 2 dB relative error at the major resonance in the frequency domain. However, it is several orders of magnitude faster in CPU time than a full SPICE simulation.

Substrate noise is a major obstacle for single-chip integration of mixed-signal systems. To reduce this problem and to assess its evolution with CMOS technology scaling, the different mechanisms that generate substrate noise and their dependencies on different parameters need to be well understood. In this paper, we show that with downscaling of the technology, substrate noise due to supply coupling becomes the dominant coupling mechanism when the chip substrate is directly biased with the digital ground. With Kelvin ground substrate biasing on the other hand, source/drain capacitive coupling becomes the dominant coupling mechanism. Further, we show that with downscaling, the peak value of the supply coupling noise component becomes more dependent on the relative ratio of the switching capacitance to the nonswitching capacitance, which is formed by the circuit decoupling and the nonswitching circuit elements, rather than the Ldi/dt noise. These insights illustrated in a quantitative framework are believed to be very useful for the systematic use of digital low-noise design techniques in future CMOS technologies.

Substrate noise coupling caused by digital switching activity on a mixed-signal IC can severely disturb RF circuits on such IC. The authors have developed an accurate approach to predict and model, prior to processing, the substrate noise generation, propagation and resulting analog and RF performance degradation. Measurements on a mixed-signal IC that contains a digital data path (40 K-gates) and an LC-VCO in a 0.18/spl mu/m CMOS process on a lightly-doped substrate, demonstrated that it is possible to understand the mechanisms of substrate noise impact and to accurately predict noise suppression by isolation techniques (a p+/n-well guard ring structure for the test case).

Comparison of digital and analog figures-of-merit of FinFETs and planar bulk MOSFETs reveals an interesting trade-off in analog/RF design space. It is seen that FinFETs possess key advantages over bulk FETs for applications around 5 GHz where the performance-power trade-off is important. In case of higher frequency applications bulk MOSFETs are shown to hold the advantage on account of their higher transconductance (Gm), provided a degraded voltage gain and a higher leakage current can be tolerated

A fully integrated 5-GHz low-power ESD-protected low-noise amplifier (LNA), designed and fabricated in a 90-nm RF CMOS technology, is presented. This 9.7-mW LNA features a 13.3-dB power gain at 5.5 GHz with a noise figure of 2.9 dB, while maintaining an input return loss of - 14 dB. An on-chip inductor, added as "plug-and-play," i.e., without altering the original LNA design, is used as ESD protection for the RF pins to achieve sufficient ESD protection. The LNA has an ESD protection level up to 1.4 A transmission line pulse (TLP) current, corresponding to 2-kV Human Body Model (HBM) stress. Experimental results show that only minor RF performance degradation is observed by adding the inductor as a bi-directional ESD protection device to the reference LNA.

Emerging impulse-based ultra-wideband (UWB) technology shows strong advantages for the implementation of low-power transceivers. In this paper we propose a carrier-based UWB system that brings two distinctive advantages over other UWB systems: 1) lower power operation due to the fact that signal processing is optimally partitioned between analog and digital baseband; 2) better spectrum utilization enabling spectrum diversity and multi-user systems. One of the core blocks in this UWB system is the pulser that serves as the transmitter RF front-end and that serves as the template generator in the receiver. We demonstrate a carrier-based low-cost and low-power UWB pulser ASIC fabricated in a 0.18 /spl mu/m CMOS digital process. The power measurements indicate that our UWB pulser ASIC outperforms the other low-data rate solutions due to its lower baseline power consumption.

Crosstalk from digital to analog in mixed-signal ICs is recognized as one of the major roadblocks for systems-on-chip (SoC) in future CMOS technologies. This crosstalk mainly happens via the semiconducting silicon substrate, which is usually treated as a ground node by analog and RF designers. The substrate noise coupling problem leads more and more to malfunctioning or extra design iterations. One of the reasons is that the phenomenon of substrate noise coupling is difficult to model and hence difficult to understand. It can be caused by the switching of thousands or millions of gates and depends on layout details. From the generation side (the digital domain), coping with the large amount of noise generators can be solved by macromodeling. On the other hand, the impact of substrate noise on the analog circuits requires careful modeling at the level of transistors and parasitics of layout, power supply, package, PCB,... Comparison to measurements of macromodeling at the digital side and careful modeling at the analog side, shows that both the generation and the impact of substrate noise can be predicted with an accuracy of a few dB. In addition, this combination of macromodeling at the digital side and careful modeling at the analog side leads to an understanding of the problem, which can be used for digital low-noise design techniques to minimize the generation of noise, and substrate noise immune design of analog/RF circuits.

Wafer-level packaging (WLP) technology offers novel opportunities for the realization of high-quality on-chip passives needed in RF front-ends. This paper demonstrates a thin-film WLP technology on top of a 90-nm RF CMOS process with one 15-GHz and two low-power 5-GHz voltage-controlled oscillators (VCOs) using a high-quality WLP or above-IC inductor. The 5-GHz VCOs have a power consumption of 0.33 mW and a phase noise of -115 dBc/Hz and -111 dBc/Hz at 1-MHz offset, respectively, and the 15-GHz VCO has a phase noise of -105 dBc/Hz at 1-MHz offset with a power consumption of 2.76 mW.

The paper reports a novel simulation methodology for the analysis and prediction of substrate noise impact on analog/RF circuits taking into account the role of the parasitic resistance of the on-chip interconnect in the impact mechanism. This methodology allows investigation of the role of the separate devices (also parasitic devices) in the analog/RF circuit in the overall impact. In this way, it is revealed which devices have to be taken care of (shielding, topology change) to protect the circuit against substrate noise. The developed methodology is used to analyze the impact of substrate noise on a 3 GHz LC-tank voltage controlled oscillator (VCO) designed in a high-ohmic 0.18 /spl mu/m 1 PM6 CMOS technology. For this VCO (in the investigated frequency range from DC to 15 MHz) impact is mainly caused by resistive coupling of noise from the substrate to the non-ideal on-chip ground interconnect, resulting in analog ground bounce and frequency modulation. Hence, the presented test-case reveals the important role of the on-chip interconnect in the phenomenon of substrate noise impact.

The successful realization of a wireless body area network (WBAN) requires innovative solutions to meet the energy consumption budget of the autonomous sensor nodes. The radio interface is a major challenge, since its power consumption must be reduced below 100 /spl mu/W (energy scavenging limit). The emerging ultra-wide-band (UWB) technology shows strong advantages in reaching this target. First, most of the complexity of an UWB system is in the receiver, which is a perfect scenario in the WBAN context. Second, the very little hardware complexity of a UWB transmitter offers the potential for low-cost and highly integrated solutions. Finally, in a pulse-based UWB scheme, the transmitter can be duty-cycled at the pulse rate, thereby reducing the baseline power consumption. We present a low-power UWB transmitter that can be fully integrated in standard CMOS technology. Measured performances of a fully integrated pulse generator are provided, showing the potential of UWB for low power and low cost implementations. Finally, using a WBAN channel model, we present a comparison between our UWB solution and state-of-the-art low-power narrow-band implementations. This paper shows that UWB performs better in the short range due to a reduced baseline power consumption.

Nowadays, a lot of effort is spent on developing inexpensive orthogonal frequency-division multiplexing (OFDM) receivers. Especially, zero intermediate frequency (zero-IF) receivers are very appealing, because they avoid costly IF filters. However, zero-IF front-ends also introduce significant additional front-end distortion, such as IQ imbalance. Moreover, zero-IF does not solve the phase noise problem. Unfortunately, OFDM is very sensitive to the receiver nonidealities IQ imbalance and phase noise. Therefore, we developed a new estimation/compensation scheme to jointly combat the IQ imbalance and phase noise at baseband. In this letter, we describe the algorithms and present the performance results. Our compensation scheme eliminates the IQ imbalance based on one OFDM symbol and performs well in the presence of phase noise. The compensation scheme has a fast convergence and a small residual degradation: even for large IQ imbalance, the overall system performance for an OFDM-wireless local area network (WLAN) case study is within 0.6 dB of the optimal case. As such, our approach greatly relaxes the mismatch specifications and thus enables low-cost zero-IF receivers.