Riccardo Brama graduated summa cum laude in 2004 from Università di Modena e Reggio Emilia, Italy, working on Class-E Power Amplifiers (PAs) and continued his research on RF PAs and Integrated Circuits Design receiving the Ph.D. degree from Università di Modenae Reggio Emilia in 2008. He worked in cooperation with STMicroelectronics and the Università di Pavia, focusing on High Speed Analog Circuits for SATA applications and mm-wave PAs. Since 2009 he is with CMC Labs, a division of CMC S.r.l. working on IoT and Cyber-Physical Systems. His current interests are in the field of communication protocols, interoperability standards, autonomous systems and wireless devices.
ABSTRACT We present a novel fully differential input/output distributed transformer topology used... more ABSTRACT We present a novel fully differential input/output distributed transformer topology used for the design of millimeter-wave power amplifiers. Input/output distributed transformers are used to feed the input signal to four differential couples and to combine their output power. This topology improves the stability and the efficiency of the power amplifier, minimizing the chip area. The PA prototype realized in a standard 65nm CMOS technology, supplied with 1.2V, achieves a 1dB single-ended output power compression point of 14dBm at 56GHz with a PAE of 8.3%, occupying only 0.2mm2.
Wireless sensor networks are drawing much attention as an effective means to enable the Internet ... more Wireless sensor networks are drawing much attention as an effective means to enable the Internet of Things. In this context, energy efficiency is an important requirement in applications where battery-powered sensing devices are exploited. Battery power saving can be addressed using many techniques, concerning different layers of the OSI model. This work addresses energy consumption in MAC protocols from a transceiver usage perspective. We first describe a set of protocols that includes IEEE 802.15.4 and IEEE 802.15.4e DSME. Then, we analyze their energy consumption and propose a set of Enhancements for Low-Power Instrumentation DSME Applications. Finally, given a wireless network topology, we compare the performance of the above mentioned protocols by simulations. Obtained results show that, for end devices, the proposed approach allows an energy consumption reduction up to a factor of 9 with respect to the IEEE 802.15.4, while enabling for higher throughput, and up to a factor of 7 with regard to native IEEE 802.15.4e DSME.
ABSTRACT A 65 nm CMOS receiver including a tapered chain linear equalization and a mixer based cl... more ABSTRACT A 65 nm CMOS receiver including a tapered chain linear equalization and a mixer based clock recovery circuit capable of SSC tracking is presented. The proposed architecture works up to 10 Gb/s with transmission channels with more than 20 dB loss at Nyquist, while consuming 110 mA and occupying 0.25 mm2.
2014 IEEE World Forum on Internet of Things (WF-IoT), 2014
ABSTRACT The ability to gather and analyze distributed data adding value to extracted information... more ABSTRACT The ability to gather and analyze distributed data adding value to extracted information is a core concept in the Internet of Things. Smart-Objects with multi-sensor capability further enhance environmental awareness with coherent and meaningful information. In this paper we first investigate a modular architecture for multi-sensors Smart-Objects allowing to ease their customization and maintainability. Then, we introduce and detail an efficient and flexible inter-device communication protocol: flexSPI. Built on top of Serial Peripheral Interface (SPI), the proposed approach allows reducing routing overhead and enabling modularity by exploiting packet-oriented messaging. To achieve these improvements, SPI bus is completely shared between connected devices avoiding conflicts by keeping free (i.e. in input direction) the Slave Output/Master Input SOMI signal and occupying it only after proper, advanced addressing. Low power and high bandwidth characteristics of SPI bus are maintained while enabling smart features such as hotpluggability, link diagnosis, devices discovery, synchronization and master solicitation.
2014 Ieee World Forum on Internet of Things, Mar 1, 2014
ABSTRACT The ability to gather and analyze distributed data adding value to extracted information... more ABSTRACT The ability to gather and analyze distributed data adding value to extracted information is a core concept in the Internet of Things. Smart-Objects with multi-sensor capability further enhance environmental awareness with coherent and meaningful information. In this paper we first investigate a modular architecture for multi-sensors Smart-Objects allowing to ease their customization and maintainability. Then, we introduce and detail an efficient and flexible inter-device communication protocol: flexSPI. Built on top of Serial Peripheral Interface (SPI), the proposed approach allows reducing routing overhead and enabling modularity by exploiting packet-oriented messaging. To achieve these improvements, SPI bus is completely shared between connected devices avoiding conflicts by keeping free (i.e. in input direction) the Slave Output/Master Input SOMI signal and occupying it only after proper, advanced addressing. Low power and high bandwidth characteristics of SPI bus are maintained while enabling smart features such as hotpluggability, link diagnosis, devices discovery, synchronization and master solicitation.
Wireless sensors networks enable the chance to
investigate with enhanced freedom physical phenome... more Wireless sensors networks enable the chance to investigate with enhanced freedom physical phenomena, aiming to increase the informative content obtained by sensors measurements. In this work we will focus on a system allowing to experimentally measure pressure profiles obtained from sensor nodes deployed on a NACA0012 aircraft wing model. By exploiting measurements gathered from sensors, allowing to measure pressure fluctuations of ±600Pa with a resolution of 4Pa, together with results obtained by Computational Fluid Dynamics (CFD) models, the system enables extracting flow profile, thus obtaining information on flow separation and stall phenomenon. Wireless measures are delivered with an enhanced version of IEEE802.15.4e, allowing to decrease power consumption by a factor of 7. Packet routing, based on Routing Protocol for Low- Power and Lossy Networks (RPL), has been improved by means of a newly introduced Lifetime and Latency Aggregatable Metric (L2AM) leading to a 18% increased network lifetime.
2006 IEEE International Reliability Physics Symposium Proceedings, 2006
ABSTRACT The target in the design of CMOS radio-frequency (RF) transceivers for wireless applicat... more ABSTRACT The target in the design of CMOS radio-frequency (RF) transceivers for wireless application is the highest integration level, despite reliability issues of conventional submicron MOSFETs, due to high RF voltage and current peaks. In this scenario, this paper investigates gate-oxide breakdown under RF stress by using a class-E power amplifier (PA) for experiments. We showed that maximum RF voltage peaks for safe device operation are much larger than usual DC limits, and that the physical mechanism of oxide degradation is triggered by the rms value of oxide field, and not by its maximum, as generally believed. This finding has a strong impact on RF circuit designs, especially in MOSFET scaling perspectives. Finally, breakdown effects on PA operations are discussed
RFIC) Symposium, 2005. Digest of Papers. 2005 IEEE Radio Frequency integrated Circuits, 2005
ABSTRACT The design of CMOS power amplifiers (PA) is still a challenging issue. Efficiency is one... more ABSTRACT The design of CMOS power amplifiers (PA) is still a challenging issue. Efficiency is one of the key requirements, but it is usually obtained at the expense of large device stress. The latter can be reduced by introducing a cascode solution, which features an efficiency penalty due to dissipative mechanisms associated with MOS capacitive parasitics, overlooked up to date. A class-E PA is proposed which allows simultaneously high efficiency and reduced stress by means of an integrated inductor tuning out the parasitic. Prototypes, realized in a 0.13 μm CMOS technology, demonstrate 67% PAE while delivering 23 dBm peak power at 1.7 GHz. PAE is still above 60% within the range 1.4-2 GHz.
ABSTRACT This paper shows that CMOS Class-E PAs are capable of high Power-Added Efficiency (PAE),... more ABSTRACT This paper shows that CMOS Class-E PAs are capable of high Power-Added Efficiency (PAE), even when delivering large output powers at Radio Frequency (RF). In particular, a cascode device is used to obtain high efficiency while assuring reliable operation. A differential solution has been adopted to maximize 2nd harmonic suppression and minimize potential on-chip interference. Prototypes realized in 0.13 mum CMOS technology using thick oxide devices show the following performances: 31 dBm maximum output power at 1.7 GHz with 67% drain efficiency and 58% PAE, -51 dBc and -39.5 dBc suppression for 2nd and 3rd harmonics, respectively.
Abstract Integration of the power amplifier together with signal processing in a transmitter is s... more Abstract Integration of the power amplifier together with signal processing in a transmitter is still missing in demanding RF commercial products. Issues preventing PA integration include LO pulling phenomena, thermal dissipation, and power efficiency. In this work we ...
ABSTRACT We present a novel fully differential input/output distributed transformer topology used... more ABSTRACT We present a novel fully differential input/output distributed transformer topology used for the design of millimeter-wave power amplifiers. Input/output distributed transformers are used to feed the input signal to four differential couples and to combine their output power. This topology improves the stability and the efficiency of the power amplifier, minimizing the chip area. The PA prototype realized in a standard 65nm CMOS technology, supplied with 1.2V, achieves a 1dB single-ended output power compression point of 14dBm at 56GHz with a PAE of 8.3%, occupying only 0.2mm2.
Wireless sensor networks are drawing much attention as an effective means to enable the Internet ... more Wireless sensor networks are drawing much attention as an effective means to enable the Internet of Things. In this context, energy efficiency is an important requirement in applications where battery-powered sensing devices are exploited. Battery power saving can be addressed using many techniques, concerning different layers of the OSI model. This work addresses energy consumption in MAC protocols from a transceiver usage perspective. We first describe a set of protocols that includes IEEE 802.15.4 and IEEE 802.15.4e DSME. Then, we analyze their energy consumption and propose a set of Enhancements for Low-Power Instrumentation DSME Applications. Finally, given a wireless network topology, we compare the performance of the above mentioned protocols by simulations. Obtained results show that, for end devices, the proposed approach allows an energy consumption reduction up to a factor of 9 with respect to the IEEE 802.15.4, while enabling for higher throughput, and up to a factor of 7 with regard to native IEEE 802.15.4e DSME.
ABSTRACT A 65 nm CMOS receiver including a tapered chain linear equalization and a mixer based cl... more ABSTRACT A 65 nm CMOS receiver including a tapered chain linear equalization and a mixer based clock recovery circuit capable of SSC tracking is presented. The proposed architecture works up to 10 Gb/s with transmission channels with more than 20 dB loss at Nyquist, while consuming 110 mA and occupying 0.25 mm2.
2014 IEEE World Forum on Internet of Things (WF-IoT), 2014
ABSTRACT The ability to gather and analyze distributed data adding value to extracted information... more ABSTRACT The ability to gather and analyze distributed data adding value to extracted information is a core concept in the Internet of Things. Smart-Objects with multi-sensor capability further enhance environmental awareness with coherent and meaningful information. In this paper we first investigate a modular architecture for multi-sensors Smart-Objects allowing to ease their customization and maintainability. Then, we introduce and detail an efficient and flexible inter-device communication protocol: flexSPI. Built on top of Serial Peripheral Interface (SPI), the proposed approach allows reducing routing overhead and enabling modularity by exploiting packet-oriented messaging. To achieve these improvements, SPI bus is completely shared between connected devices avoiding conflicts by keeping free (i.e. in input direction) the Slave Output/Master Input SOMI signal and occupying it only after proper, advanced addressing. Low power and high bandwidth characteristics of SPI bus are maintained while enabling smart features such as hotpluggability, link diagnosis, devices discovery, synchronization and master solicitation.
2014 Ieee World Forum on Internet of Things, Mar 1, 2014
ABSTRACT The ability to gather and analyze distributed data adding value to extracted information... more ABSTRACT The ability to gather and analyze distributed data adding value to extracted information is a core concept in the Internet of Things. Smart-Objects with multi-sensor capability further enhance environmental awareness with coherent and meaningful information. In this paper we first investigate a modular architecture for multi-sensors Smart-Objects allowing to ease their customization and maintainability. Then, we introduce and detail an efficient and flexible inter-device communication protocol: flexSPI. Built on top of Serial Peripheral Interface (SPI), the proposed approach allows reducing routing overhead and enabling modularity by exploiting packet-oriented messaging. To achieve these improvements, SPI bus is completely shared between connected devices avoiding conflicts by keeping free (i.e. in input direction) the Slave Output/Master Input SOMI signal and occupying it only after proper, advanced addressing. Low power and high bandwidth characteristics of SPI bus are maintained while enabling smart features such as hotpluggability, link diagnosis, devices discovery, synchronization and master solicitation.
Wireless sensors networks enable the chance to
investigate with enhanced freedom physical phenome... more Wireless sensors networks enable the chance to investigate with enhanced freedom physical phenomena, aiming to increase the informative content obtained by sensors measurements. In this work we will focus on a system allowing to experimentally measure pressure profiles obtained from sensor nodes deployed on a NACA0012 aircraft wing model. By exploiting measurements gathered from sensors, allowing to measure pressure fluctuations of ±600Pa with a resolution of 4Pa, together with results obtained by Computational Fluid Dynamics (CFD) models, the system enables extracting flow profile, thus obtaining information on flow separation and stall phenomenon. Wireless measures are delivered with an enhanced version of IEEE802.15.4e, allowing to decrease power consumption by a factor of 7. Packet routing, based on Routing Protocol for Low- Power and Lossy Networks (RPL), has been improved by means of a newly introduced Lifetime and Latency Aggregatable Metric (L2AM) leading to a 18% increased network lifetime.
2006 IEEE International Reliability Physics Symposium Proceedings, 2006
ABSTRACT The target in the design of CMOS radio-frequency (RF) transceivers for wireless applicat... more ABSTRACT The target in the design of CMOS radio-frequency (RF) transceivers for wireless application is the highest integration level, despite reliability issues of conventional submicron MOSFETs, due to high RF voltage and current peaks. In this scenario, this paper investigates gate-oxide breakdown under RF stress by using a class-E power amplifier (PA) for experiments. We showed that maximum RF voltage peaks for safe device operation are much larger than usual DC limits, and that the physical mechanism of oxide degradation is triggered by the rms value of oxide field, and not by its maximum, as generally believed. This finding has a strong impact on RF circuit designs, especially in MOSFET scaling perspectives. Finally, breakdown effects on PA operations are discussed
RFIC) Symposium, 2005. Digest of Papers. 2005 IEEE Radio Frequency integrated Circuits, 2005
ABSTRACT The design of CMOS power amplifiers (PA) is still a challenging issue. Efficiency is one... more ABSTRACT The design of CMOS power amplifiers (PA) is still a challenging issue. Efficiency is one of the key requirements, but it is usually obtained at the expense of large device stress. The latter can be reduced by introducing a cascode solution, which features an efficiency penalty due to dissipative mechanisms associated with MOS capacitive parasitics, overlooked up to date. A class-E PA is proposed which allows simultaneously high efficiency and reduced stress by means of an integrated inductor tuning out the parasitic. Prototypes, realized in a 0.13 μm CMOS technology, demonstrate 67% PAE while delivering 23 dBm peak power at 1.7 GHz. PAE is still above 60% within the range 1.4-2 GHz.
ABSTRACT This paper shows that CMOS Class-E PAs are capable of high Power-Added Efficiency (PAE),... more ABSTRACT This paper shows that CMOS Class-E PAs are capable of high Power-Added Efficiency (PAE), even when delivering large output powers at Radio Frequency (RF). In particular, a cascode device is used to obtain high efficiency while assuring reliable operation. A differential solution has been adopted to maximize 2nd harmonic suppression and minimize potential on-chip interference. Prototypes realized in 0.13 mum CMOS technology using thick oxide devices show the following performances: 31 dBm maximum output power at 1.7 GHz with 67% drain efficiency and 58% PAE, -51 dBc and -39.5 dBc suppression for 2nd and 3rd harmonics, respectively.
Abstract Integration of the power amplifier together with signal processing in a transmitter is s... more Abstract Integration of the power amplifier together with signal processing in a transmitter is still missing in demanding RF commercial products. Issues preventing PA integration include LO pulling phenomena, thermal dissipation, and power efficiency. In this work we ...
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Papers by R. Brama
investigate with enhanced freedom physical phenomena, aiming
to increase the informative content obtained by sensors measurements.
In this work we will focus on a system allowing to
experimentally measure pressure profiles obtained from sensor
nodes deployed on a NACA0012 aircraft wing model. By exploiting
measurements gathered from sensors, allowing to measure
pressure fluctuations of ±600Pa with a resolution of 4Pa,
together with results obtained by Computational Fluid Dynamics
(CFD) models, the system enables extracting flow profile, thus
obtaining information on flow separation and stall phenomenon.
Wireless measures are delivered with an enhanced version of
IEEE802.15.4e, allowing to decrease power consumption by a
factor of 7. Packet routing, based on Routing Protocol for Low-
Power and Lossy Networks (RPL), has been improved by means
of a newly introduced Lifetime and Latency Aggregatable Metric
(L2AM) leading to a 18% increased network lifetime.
investigate with enhanced freedom physical phenomena, aiming
to increase the informative content obtained by sensors measurements.
In this work we will focus on a system allowing to
experimentally measure pressure profiles obtained from sensor
nodes deployed on a NACA0012 aircraft wing model. By exploiting
measurements gathered from sensors, allowing to measure
pressure fluctuations of ±600Pa with a resolution of 4Pa,
together with results obtained by Computational Fluid Dynamics
(CFD) models, the system enables extracting flow profile, thus
obtaining information on flow separation and stall phenomenon.
Wireless measures are delivered with an enhanced version of
IEEE802.15.4e, allowing to decrease power consumption by a
factor of 7. Packet routing, based on Routing Protocol for Low-
Power and Lossy Networks (RPL), has been improved by means
of a newly introduced Lifetime and Latency Aggregatable Metric
(L2AM) leading to a 18% increased network lifetime.