Percorrer por autor "Mendes, P.M."
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- A 2.4 GHz wireless electronic shirt for vital signals monitoringPublication . Carmo, João Paulo; Mendes, P.M.; Couto, Carlos; Correia, José H.The paper presents a wireless sensor network for wireless electronic shirts. This allows the monitoring of individual biomedical data, such as the cardio-respiratory function. The solution chosen to transmit the body’s measured signals for further processing was the use of a wireless link, working at the 2.4 GHz ISM band. A radio-frequency (RF) CMOS transceiver chip was designed in the UMC RF 0.18 μm CMOS process. The power supply of the RF CMOS transceiver is of only 1.5 V, thus it can be supplied by a single coin-sized battery. The receiver has a sensibility of -60 dBm and consumes 6.2 mW. The transmitter delivers an output power of 0 dBm with a power consumption of 15.6 mW. Innovative topics concerning efficient power management was taken into account during the design of the RF CMOS transceiver.
- 2.4 GHz wireless sensor network for smart electronic shirtsPublication . Carmo, João Paulo; Mendes, P.M.; Couto, Carlos; Correia, José H.This paper presents a wireless sensor network for smart electronic shirts. This allows the monitoring of individual biomedical data, such the cardio-respiratory function. The solution chosen to transmit the body’s measured signals for further processing was the use of a wireless link, working at the 2.4 GHz ISM band. A radio-frequency transceiver chip was designed in a UMC RF 0.18 μm CMOS process. The power supply of the transceiver is 1.8 V. Simulations show a power consumption of 12.9 mW. Innovative topics concerning efficient power management was taken into account during the design of the transceiver.
- A 2.4-GHz low-power/low-voltage wireless plug-and-play module for EEG applicationsPublication . Carmo, João Paulo; Dias, Nuno; Silva, Hélder; Mendes, P.M.; Couto, Carlos; Correia, José H.This paper presents a plug-and-play module for wireless electroencephalogram (EEG) applications. The wireless module is composed by an electrode, processing electronics, a radio-frequency (RF) transceiver, and an associated antenna. The RF transceiver was fabricated in the UMC RF 0.18 mum CMOS process, and operates in the 2.4-GHz ISM band. The receiver has a sensitivity of -60 dBm and a power consumption of 6.3 mW from a 1.8 V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW, for a range of 10 m. It is also presented the electrical performance and comparison between different electrodes for EEG applications, namely sputtered titanium nitride (TiN) electrodes, standard sintered silver/silver chloride (Ag/AgCl) ring electrodes and sputtered iridium oxide (IrO2) electrodes. The experimental results show a better performance of the sputtered IrO2 electrodes compared with the standard sintered Ag/AgCl ring electrodes. These results promise a new opportunity for the application of a dry IrO2 electrodes in wireless modules for using in a wearable EEG braincap. These wireless EEG modules will allow patients to wear a brain cap and maintain their mobility, while simultaneously having their electrical brain activity monitored.
- A 2.4-GHz RF CMOS transceiver for wireless sensor applicationsPublication . Carmo, João Paulo; Mendes, P.M.; Couto, Carlos; Correia, José H.The paper describes a radio frequency transceiver designed in UMC RF 0.18 µm CMOS process. This process has a poly and six metal layers, allowing the use of integrated spiral inductors (with a reasonable quality factor), high resistor value (a special layer is available) and a low-power supply of 1.8 V. This RF CMOS transceiver will be applied to implemented a wireless sensors network in a wireless electronic shirt for helping health professionals with rapid, accurate and sophisticated diagnostic concerning cardiopulmonary disease in order to evaluate the presence of breathing disorders in free-living patients. Without proper design, communication will increase network power consumption significantly because listening and emitting are power-intensive activities. Thus, in order to optimise power consumption, it was included in the design of the RF transceiver, the use of control signals. With these control signals it is possible to enable and disable all the transceiver subsystems. These signals allows for example to switch off the receiver when a RF signal is being transmitted, to switch off the transmitter when a RF signal is being received, and to put the transceiver in sleeping mode when neither RF signals are being transmitted, nor being received.
- A 2.4-GHz wireless sensor network for smart electronic shirts integrationPublication . Carmo, João Paulo; Mendes, P.M.; Afonso, José A.; Couto, Carlos; Correia, José H.A typical sensing module is composed of sensors, interface electronics, a radio-frequency (RF) CMOS transceiver and an associated antenna. A 2.4-GHz RF transceiver chip was fabricated in a UMC 0.18 μm CMOS process. The receiver has a sensibility of -60 dBm and consumes 6.3 mW from a 1.8 V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW. Innovative topics concerning efficient power management was taken into account during the design of the transceiver. A solution of individual sensing modules allows a plug-and-play solution. The target application is the integration of a wireless sensor network in smart electronic shirts, for monitoring the cardio-respiratory function and posture.
- 5.7 GHz on-chip antenna/RF CMOS transceiver for wireless sensor networkSPublication . Carmo, João Paulo; Mendes, P.M.; Couto, Carlos; Correia, José H.This paper describes a chip-size antenna for operation at 5.7 GHz, assembled with a low-power, low-voltage RF CMOS transceiver, fabricated in UMC RF CMOS 0.18 μm process. Measurements shown a patch antenna with the central frequency of 5.705 GHz, a bandwidth of 90 MHz at −10 dB of return loss, a directive gain of 0.3 dB, with an efficiency of 18%, and a transceiver with a measured total power consumption of 23 mW. This microsystem is intended for the use in each wireless node of a wireless sensor network mounted in a wireless electronic shirt, that monitors the cardio-respiratory function and posture.
- Effects of the ESD protections in the behaviour of a 2.4 GHz RF transceiver: problems and solutionsPublication . Carmo, João Paulo; Mendes, P.M.; Ribeiro, Fernando; Correia, José H.This paper identifies the main problems related to the Electrostatic Discharge (ESD) in submicron CMOS processes. The mitigation of this problem is made with the use of protections, in order to avoid the destruction of the internal and nput/output circuits connected to the bondingpads. In the 2.4 GHz ISM band, the parallel capacitance and the serial resistance of the ESD protections have effects in the behavior of RF transceivers. The major identified effect was the transmission range. It is proposed two strategies to solve the secondary effects, due to the protections. All the measurements and simulations were made for a 2.4 GHz RF CMOS transceiver, designed and fabricated using the UMC 0.18 µm RF CMOS process.
- Low-power 2.4-GHz RF transceiver for wireless EEG module plug-and-playPublication . Carmo, João Paulo; Dias, Nuno; Mendes, P.M.; Couto, Carlos; Correia, José H.The paper presents the design and fabrication of a radio-frequency (RF) transceiver fabricated in a UMC RF 0.18 µm CMOS process. The RF transceiver was built to operate at the 2.4 GHz ISM band. The receiver has a sensibility of -60 dBm and consumes 6.3 mW from a 1.8 V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW. The application is a wireless wearable electroencephalogram (EEG) braincap. Wireless EEG allows patients to wear the brain cap and maintain their mobility while simultaneously having their electrical brain activity monitored. A solution of an individual EEG module composed by an electrode, processing electronics and an antenna, allows a plug-and-play electrodes solution.