6 research outputs found

    Advances in Integrated Circuit Design and Implementation for New Generation of Wireless Transceivers

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    User’s everyday outgrowing demand for high-data and high performance mobile devices pushes industry and researchers into more sophisticated systems to fulfill those expectations. Besides new modulation techniques and new system designs, significant improvement is required in the transceiver building blocks to handle higher data rates with reasonable power efficiency. In this research the challenges and solution to improve the performance of wireless communication transceivers is addressed. The building block that determines the efficiency and battery life of the entire mobile handset is the power amplifier. Modulations with large peak to average power ratio severely degrade efficiency in the conventional fixed-biased power amplifiers (PAs). To address this challenge, a novel PA is proposed with an adaptive load for the PA to improve efficiency. A nonlinearity cancellation technique is also proposed to improve linearity of the PA to satisfy the EVM and ACLR specifications. Ultra wide-band (UWB) systems are attractive due to their ability for high data rate, and low power consumption. In spite of the limitation assigned by the FCC, the coexistence of UWB and NB systems are still an unsolved challenge. One of the systems that is majorly affected by the UWB signal, is the 802.11a system (5 GHz Wi-Fi). A new analog solution is proposed to minimize the interference level caused by the impulse Radio UWB transmitter to nearby narrowband receivers. An efficient 400 Mpulse/s IR-UWB transmitter is implemented that generates an analog UWB pulse with in-band notch that covers the majority of the UWB spectrum. The challenge in receiver (RX) design is the over increasing out of blockers in applications such as cognitive and software defined radios, which are required to tolerate stronger out-of-band (OB) blockers. A novel RX is proposed with a shunt N-path high-Q filter at the LNA input to attenuate OB-blockers. To further improve the linearity, a novel baseband blocker filtering techniques is proposed. A new TIA has been designed to maintain the good linearity performance for blockers at large frequency offsets. As a result, a +22 dBm IIP3 with 3.5 dB NF is achieved. Another challenge in the RX design is the tough NF and linearity requirements for high performance systems such as carrier aggregation. To improve the NF, an extra gain stage is added after the LNA. An N-path high-Q band-pass filter is employed at the LNA output together with baseband blocker filtering technique to attenuate out-of-band blockers and improve the linearity. A noise-cancellation technique based on the frequency translation has been employed to improve the NF. As a result, a 1.8dB NF with +5 dBm IIP3 is achieved. In addition, a new approach has been proposed to reject out of band blockers in carrier aggregation scenarios. The proposed solution also provides carrier to carrier isolation compared to typical solution for carrier aggregation

    Energy-Efficient Wireless Circuits and Systems for Internet of Things

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    As the demand of ultra-low power (ULP) systems for internet of thing (IoT) applications has been increasing, large efforts on evolving a new computing class is actively ongoing. The evolution of the new computing class, however, faced challenges due to hard constraints on the RF systems. Significant efforts on reducing power of power-hungry wireless radios have been done. The ULP radios, however, are mostly not standard compliant which poses a challenge to wide spread adoption. Being compliant with the WiFi network protocol can maximize an ULP radio’s potential of utilization, however, this standard demands excessive power consumption of over 10mW, that is hardly compatible with in ULP systems even with heavy duty-cycling. Also, lots of efforts to minimize off-chip components in ULP IoT device have been done, however, still not enough for practical usage without a clean external reference, therefore, this limits scaling on cost and form-factor of the new computer class of IoT applications. This research is motivated by those challenges on the RF systems, and each work focuses on radio designs for IoT applications in various aspects. First, the research covers several endeavors for relieving energy constraints on RF systems by utilizing existing network protocols that eventually meets both low-active power, and widespread adoption. This includes novel approaches on 802.11 communication with articulate iterations on low-power RF systems. The research presents three prototypes as power-efficient WiFi wake-up receivers, which bridges the gap between industry standard radios and ULP IoT radios. The proposed WiFi wake-up receivers operate with low power consumption and remain compatible with the WiFi protocol by using back-channel communication. Back-channel communication embeds a signal into a WiFi compliant transmission changing the firmware in the access point, or more specifically just the data in the payload of the WiFi packet. With a specific sequence of data in the packet, the transmitter can output a signal that mimics a modulation that is more conducive for ULP receivers, such as OOK and FSK. In this work, low power mixer-first receivers, and the first fully integrated ultra-low voltage receiver are presented, that are compatible with WiFi through back-channel communication. Another main contribution of this work is in relieving the integration challenge of IoT devices by removing the need for external, or off-chip crystals and antennas. This enables a small form-factor on the order of mm3-scale, useful for medical research and ubiquitous sensing applications. A crystal-less small form factor fully integrated 60GHz transceiver with on-chip 12-channel frequency reference, and good peak gain dual-mode on-chip antenna is presented.PHDElectrical and Computer EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/162975/1/jaeim_1.pd

    Microwave and Millimeter-wave Concurrent Multiband Low-Noise Amplifiers and Receiver Front-end in SiGe BiCMOS Technology

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    A fully integrated SiGe BiCMOS concurrent multiband receiver front-end and its building blocks including multiband low-noise amplifiers (LNAs), single-to-differential amplifiers and mixer are presented for various Ku-/K-/Ka-band applications. The proposed concurrent multiband receiver building blocks and receiver front-end achieve the best stopband rejection performances as compared to the existing multiband LNAs and receivers. First, a novel feedback tri-band load composed of two inductor feedback notch filters is proposed to overcome the low Q-factor of integrated passive inductors, and hence it provides superior stopband rejection ratio (SRR). A new 13.5/24/35-GHz concurrent tri-band LNA implementing the feedback tri-band load is presented. The developed tri-band LNA is the first concurrent tri-band LNA operating up to millimeter-wave region. By expanding the operating principle of the feedback tri-band load, a 21.5/36.5-GHz concurrent dual-band LNA with an inductor feedback dual-band load and another 23/36-GHz concurrent dual-band LNA with a new transformer feedback dual-band load are also presented. The latter provides more degrees of freedom for the creation of the stopband and passbands as compared to the former. A 22/36-GHz concurrent dual-band single-to-differential LNA employing a novel single-to-differential transformer feedback dual-band load is presented. The developed LNA is the first true concurrent dual-band single-to-differential amplifier. A novel 24.5/36.5 GHz concurrent dual-band merged single-to-differential LNA and mixer implementing the proposed single-to-differential transformer feedback dual-band load is also presented. With a 21-GHz LO signal, the down-converted dual IF bands are located at 3.5/15.5 GHz for two passband signals at 24.5/36.5 GHz, respectively. The proposed merged LNA and mixer is the first fully integrated concurrent dual-band mixer operating up to millimeter-wave frequencies without using any switching mechanism. Finally, a 24.5/36.5-GHz concurrent dual-band receiver front-end is proposed. It consists of the developed concurrent dual-band LNA using the single-to-single transformer feedback dual-band load and the developed concurrent dual-band merged LNA and mixer employing the single-to-differential transformer feedback dual-band load. The developed concurrent dual-band receiver front-end achieves the highest gain and the best NF performances with the largest SRRs, while operating at highest frequencies up to millimeter-wave region, among the concurrent dual-band receivers reported to date

    Microwave and Millimeter-wave Concurrent Multiband Low-Noise Amplifiers and Receiver Front-end in SiGe BiCMOS Technology

    Get PDF
    A fully integrated SiGe BiCMOS concurrent multiband receiver front-end and its building blocks including multiband low-noise amplifiers (LNAs), single-to-differential amplifiers and mixer are presented for various Ku-/K-/Ka-band applications. The proposed concurrent multiband receiver building blocks and receiver front-end achieve the best stopband rejection performances as compared to the existing multiband LNAs and receivers. First, a novel feedback tri-band load composed of two inductor feedback notch filters is proposed to overcome the low Q-factor of integrated passive inductors, and hence it provides superior stopband rejection ratio (SRR). A new 13.5/24/35-GHz concurrent tri-band LNA implementing the feedback tri-band load is presented. The developed tri-band LNA is the first concurrent tri-band LNA operating up to millimeter-wave region. By expanding the operating principle of the feedback tri-band load, a 21.5/36.5-GHz concurrent dual-band LNA with an inductor feedback dual-band load and another 23/36-GHz concurrent dual-band LNA with a new transformer feedback dual-band load are also presented. The latter provides more degrees of freedom for the creation of the stopband and passbands as compared to the former. A 22/36-GHz concurrent dual-band single-to-differential LNA employing a novel single-to-differential transformer feedback dual-band load is presented. The developed LNA is the first true concurrent dual-band single-to-differential amplifier. A novel 24.5/36.5 GHz concurrent dual-band merged single-to-differential LNA and mixer implementing the proposed single-to-differential transformer feedback dual-band load is also presented. With a 21-GHz LO signal, the down-converted dual IF bands are located at 3.5/15.5 GHz for two passband signals at 24.5/36.5 GHz, respectively. The proposed merged LNA and mixer is the first fully integrated concurrent dual-band mixer operating up to millimeter-wave frequencies without using any switching mechanism. Finally, a 24.5/36.5-GHz concurrent dual-band receiver front-end is proposed. It consists of the developed concurrent dual-band LNA using the single-to-single transformer feedback dual-band load and the developed concurrent dual-band merged LNA and mixer employing the single-to-differential transformer feedback dual-band load. The developed concurrent dual-band receiver front-end achieves the highest gain and the best NF performances with the largest SRRs, while operating at highest frequencies up to millimeter-wave region, among the concurrent dual-band receivers reported to date
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