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At rates of 100Gb/s and above, CMOS DSP-based transceivers integrated with high-sampling-rate data converters are critical to realize the phase-sensitive modulation schemes based on coherent detection that are essential to metro and long-haul networks [1]. To support dual-polarization QPSK format, quad low-power DACs and ADCs are needed and precise phase alignment has to be maintained between XI, XQ, YI, and YQ channels, in order to transmit and extract the phase information in the coherent system, as shown in Fig. 29.2.1. For long-haul transmission at 100Gb/s, because of the FEC overhead, the baud rate per channel can be as high as 32Gb/s. In addition, the receiver often requires double sampling at 64GS/s for robust clock-data recovery and SNR improvement for stressed channels. Double sampling also enables the DSP to implement more complicated equalization schemes and more flexible spectrum engineering at high frequency on the transmitter side. This paper reports the receiver and transmitter fully integrated in a 100G coherent DSP chip, using 4×64GS/s ADCs and DACs with 8b resolution, fabricated in a standard 20nm CMOS process.

A multi-modal transit station is a complex system in the urban system and takes important roles in our daily life. Since various transportation systems a large scale of passenger participates to the station, design and analysis of the multi-modal transit station are important problem. This paper presents a modeling and simulation method to support designing the transit station. First, we introduce the modeling method to build a simulation models to capture the behavior of vehicles and the crowds using the Discrete Event System (DEVS) formalism. Then, we introduce a simulation environment for multi-modal transit station which is based on the DEVSim++. In this simulation environment, we support requirement verification method based on the untimed DEVS model, and it checks the requirements by executing the simulation model and the untimed DEVS model altogether.

This paper reports a continuously tunable lumped bandpass filter implemented in a third-order coupled resonator configuration. The filter is fabricated on a Borosilicate glass substrate using a surface micromachining technology that offers hightunable passive components. Continuous electrostatic tuning is achieved using three tunable capacitor banks, each consisting of one continuously tunable capacitor and three switched capacitors with pull-in voltage of less than 40 V. The center frequency of the filter is tuned from 1 GHz down to 600 MHz while maintaining a 3-dB bandwidth of 13%-14% and insertion loss of less than 4 dB. The maximum group delay is less than 10 ns across the entire tuning range. The temperature stability of the center frequency from -50°C to 50°C is better than 2%. The measured tuning speed of the filter is better than 80 s, and the is better than 20 dBm, which are in good agreement with simulations. The filter occupies a small size of less than 1.5 cm × 1.1 cm. The implemented filter shows the highest performance amongst the fully integrated microelectromechanical systems filters operating at sub-gigahertz range.

This paper reports on the implementation of miniaturized ultra-wideband filters integrated with tunable notch filters using a silicon-based integrated passive device technology. An ultra-wideband bandpass filter is realized on a micromachined silicon substrate, showing an insertion loss of 1.1 dB, return loss of better than 15 dB, and attenuation of more than 30 dB at both lower and upper stop-bands, with a spurious-free response up to 40 GHz. The filter occupies only 2.9 mm 2.4 mm of die area. To address the in-band interference issues associated with ultra-wideband communication, very compact tunable notch filters are monolithically integrated with the bandpass filters. A two-pole tunable notch filter integrated with an ultra-wideband filter provides more than 20 dB rejection in the 5-6 GHz range to reject U-NII interferences, with a total footprint of 4.8 mm 2.9 mm. The power handling, linearity, and temperature stability of filters are characterized and presented in this paper.

In this letter, we report on the design, fabrication, and measured results of a directly heated phase change RF switch (or via) using germanium telluride in a four-terminal configuration. The switch is heated using a separate heater path combining the advantages of directly heated vias, such as low power dissipation for phase transition, and indirectly heated vias, such as high power handling capability. The phase change switch shows an insertion loss of less than 0.6 dB and an isolation of higher than 20 dB at frequencies up to 20 GHz, indicating a cutoff frequency of more than 3.7 THz. The switch area is only 4 μm× 6 μm, which is smaller than RF MEMS switches with similar insertion loss performance. To the best of our knowledge, this is the first report on a four-terminal, directly heated, RF phase change switch.

We report on a thermoelectric model that can be used to analyze the nonlinearity and power handling capability of RF switches based on phase change (PC) materials. To analyze the nonlinear behavior of the PC switches, the Poole-Frenkel effect, the variation of thermal and electrical conductance with temperature, and the effect of Joule heating with increased RF signal power are all taken into account. The simulated input third-order intercept point and the 1-dB compression point (P1dB) are compared with measured results of directly heated PC switches, showing a good agreement. Using this model, we provide insights into the effect of electrical resistance, and thermal properties, as well as the operation frequency on the switch nonlinearity and power handling capability.

Diverse RF passive devices and microelectro- mechanical systems (MEMS) can be monolithically integrated on a high-resistivity silicon (HR-Si) substrate. However, parasitic surface conduction (PSC) at the interface of HR-Si and a silicon dioxide (SiO2) passivation layer reduces the effective substrate resistivity, which in turn results in deterioration of the device quality factor (Q) and non-linearity. Trap-rich HR-Si has been proposed as a low substrate loss alternative, eliminating the problems associated with PSC. However, the full potential of trap-rich HR-Si as a common platform for implementing MEMS passives is not fully explored. In this letter, we evaluate the effectiveness of the trap-rich layer by comparing the frequency response of a number of RF passive devices fabricated on standard and trap-rich HR-Si substrates. In addition, we suggest an electromagnetic (EM) simulation setup that can be used to efficiently and accurately simulate the device performance.

RF losses and non-linear behavior of RF passive elements such as coplanar transmission lines and inductors are analyzed. The investigated trap-rich HR-Si wafers with a fixed oxide layer of 150 nm-thick show true effective resistivity values higher than 4 kΩ-cm up to 5 GHz and harmonic distortion levels lower than −90 dBm for a 900 MHz input with signal level of +25 dBm. High quality factor of 60 is measured for a 2 nH inductor on a trap-rich HR-Si substrate at 2.73 GHz frequency of operation. Our investigations confirm the capability of trap-rich HR-SOI wafer for the integration of passive elements for RF systems.

Phase change materials are attractive candidates for use in ohmic switches as they can be thermally transitioned between amorphous and crystalline states, showing several orders of magnitude change in resistivity. Phase change switches are fast, small form factor, and can be readily integrated with MEMS and CMOS electronics. As such, they have a great potential for implementing next-generation high-speed reconfigurable RF modules. In this paper, we report on the RF properties of germanium tellurium, a PC material, and its use in RF switching applications. Intrinsic resistance and capacitance at the ON (crystalline) and OFF (amorphous) states of a directly heated switch are compared and characterized. Other properties such as phase transition conditions, insertion loss, return loss, and power handling capability of the switch are also measured and analyzed.

This paper reports on a high-performance MEMS lumped bandpass filter continuously tuned from 1 GHz to 0.6 GHz using 12 electrostatically actuated MEMS capacitors. To demonstrate the benefits of MEMS technologies, a reconfigurable filter array is implemented on a PCB using SMT components and its performance is compared to that of the MEMS filter. Besides the advantage in size, the MEMS filter also exhibits lower loss and greater rejection. To become a viable solution for RF applications, other performance specifications of MEMS filters such as tuning speed and reliability need to be improved.

This paper reports on micromachined tunable bandstop filters that exhibit an octave frequency tuning range with high stopband rejection and low out-of-band loss. In addition to continuous frequency tuning, stopband switch on-off capability is realized by employing ohmic switches along with tunable capacitors. The fully re-configurable filters in this work are fabricated using a silicon-based integrated passive device technology and are the smallest-size bandstop filters reported in the low SHF range.

Summary form only given, as follows. Miniaturized UWB filters with low loss, steep rejection, and spurious-free response on a silicon substrate are reported. A UWB filter is demonstrated with less than 1 dB insertion loss, more than 30 dB stop-band rejection, occupying 2.9 mm × 2.4 mm of die area. A UWB filter with a notch filter is presented having a footprint of 4.6 mm × 2.9 mm. The notch filter centered at 5.285 GHz provides a maximum attenuation of 23 dB with 10 dB bandwidth of 7% and shows excellent temperature stability.

This paper reports on the implementation of miniaturized UWB filters with low loss, steep rejection, and spurious-free response on a silicon substrate. A UWB filter is demonstrated with an insertion loss of less than 1 dB, 3 dB bandwidth of 7.25 GHz, attenuation of more than 30 dB in both the lower (10 MHz–2.6 GHz) and the upper (12 GHz–20 GHz) stop-bands, occupying only 2.9 mm × 2.4 mm of die area. In addition, a novel design is proposed for the implementation of a narrowband notch filter, which can be integrated with UWB bandpass filters for rejecting strong in-band interferences. A UWB filter integrated with a notch filter is presented having a total footprint of 4.6 mm × 2.9 mm. The notch filter centered at 5.285 GHz provides a maximum attenuation of 23 dB with 10 dB fractional bandwidth of 7% to reject WLAN/WiMAX interferences. The temperature stability of the notch filter is better than 0.4 % in the temperature range of −30 °C to 70 °C.

This paper reports on a continuously tunable MEMS capacitor with a wide tuning range of 5∶1, high quality factor of better than 100 (at 1 GHz) at each tuned state, and self-resonance frequency of more than 13.5 GHz. The temperature stability of the capacitance in the temperature range of −50 °C to 60 °C is better than 7%, which is one of the best reported for continuously tuned capacitors. The maximum tuning speed of the capacitor is measured to be better than 40 µsec.

We report on the experimental verification of the acoustoelectric effect in gallium nitride (GaN) and present a model to describe this effect in GaN thickness-mode bulk acoustic filters. Filters are fabricated using 2.2 µm thick n-type GaN on high resistivity silicon epiwafers obtained from SOITEC. Acoustoelectric effect was observed by applying an electric field parallel to c-axis, the direction of acoustic wave propagation. Improvement in the insertion loss and out-of-band rejection was observed and Q amplifications exceeding 240% was achieved. Acoustoelectric effect makes it possible to dynamically tune the frequency response of GaN resonators and filters.

This paper reports on a new implementation of integrated lumped filters with improved out-of-band rejection and passband loss. Inductive parasitics are exploited to provide additional transmission zeros at the high frequency end, which can improve both the out-of-band rejection and roll-off. Thick silver is electroplated to reduce the insertion loss and achieve high quality factor. An insertion loss of better than 3dB has been achieved for filters across 220MHz to 640MHz with unloaded Q as high as 50. The out-of-band rejection of filters is as high as 60dB. These are believed to be the highest performing integrated filters in terms of out-of-band attenuation and spurious-free response implemented on silicon substrate.

The rapid growth of data center traffic, driven by cloud technology adoption, has propelled the development of a variety of spectrally efficient modulation formats, such as 4-level pulse amplitude modulation (PAM4), quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM). High speed CMOS DSP-based transceivers provide complex equalization scheme to compensate for the channel loss as well as the nonlinearity impairments introduced by chromatic and polarization dispersion. The recent development of ultra-high speed data converters has been a key enabling technology converting data signal between analog and digital domain, which has shaped the traditional communication transceiver systems. This paper covers the advancement of CMOS data converter technology and its wide application, as well as the future development and trend.