Ricardo Meneses Gonzalez

The formation of open-chain thioesters in the reaction of 2-lithio-2-methyl- and 2-lithio-2-phenyl-1,3-dithiane with chlorodiphenylphosphane followed by oxidation ☆

The unexpected formation of open-chain thioesters (3) and (6) from the reaction of 2-lithio-r-2-t-4-t-6-trimethyl (1-Li) and 2-lithio-r-2-phenyl-t-4-t-6-dimethyl-1,3-dithiane (4-Li), respectively, with chlorodiphenylphosphane followed by oxidation was observed instead of the anticipated gem-derivatives. The X-ray diffraction analysis of (6) and the trapped intermediate (10) confirmed the structure and the proposed mechanism of formation of the open-chain products.

Modeling the RFID radio channel applied to vehicular identification as a waveguide environment

Radio Frequency Identification (RFID) Systems are a wireless communication. Recently they are being applied to vehicular identification in road and freeways. This motivates the analysis of the propagation environment for outdoor in such systems. The RFID Systems that are used for the vehicular identification consists of the reader, the tag and the radio channel which is made up on the ground (asphalt), the free space and surrounded by irregular walls (buses, vans, sport cars, etc., located at adjacent lanes). In this work, the radio channel considering a tunnel environment and modeling as a waveguide is analyzed, in order to obtain the electromagnetic performance of the radio channel. The results show that the proposed model is suitable.

Dual frequency Microstrip Antenna design for 700 MHz UHF Band and Wlan Application

Recently Terrestrial Digital Television, TDT, has been implemented in Mexico, as a consequence, the 700 MHZ UHF Band has been opened to new telecommunications services, particularly wireless mobile communication. This technological advance means an antenna design challenge due to it is necessary to design a dual frequency antenna which dimensions must be enough small, satisfy gain, resonance frequency, impedance, wideband requirements, and low cost, in that sense, this work describes the simulation, design and implementation of Microstrip Antenna for 700 MHZ UHF Band (698–806 MHz) and for Wireless Lan Application, (2400–2483.5 GHz Wi Fi ISM) to be used on radio mobile devices.

Spiral Slotted Microstrip Antenna Design for 700 MHz Band Application

This work describes the design and implementation of spiral slotted microstrip antenna. Recently, just like other countries, in Mexico, terrestrial digital television has been implemented (analogic shutdown); as a consequence, the 700 MHz UFH Band (698–806 MHz) has been opened to new telecommunications services, particularly wireless mobile communication. This technological advance represents a radio mobile antenna design challenge because it is necessary to design an antenna whose dimensions must be small enough, which satisfies gain, resonance frequency, and bandwidth requirements and is of low cost.

RFID tag antenna design applied to the public health system as identification alternative

This work describes the design and implementation of a loop antenna altered by a parasitic structure, using the meander line technique, to be used as 915 MHz UHF RFID tag antenna. In order to determine the performance of varying design parameters on impedance, resonance frequency, radiation pattern, polarization, etc., HFSS simulation software has been used and experimental tests under an anechoic camera have been applied. The achieved results show the feasibility of the designed antenna to be installed on the wrist patient, as a identification alternative to be applied to the public health system, in order to be identified inside hospitals.

Discovering spectrum holes in a specific indoor environment for cognitive radio application

This works makes a brief review of the current situation, first principles and objectives of Cognitive Radio, as well as, measurements of the electromagnetic environment in the 800–900 MHz UHF Band are carried out in a specific indoor environment in order to analyze and discover spectrum holes to be used by a cognitive receiver for creating white spaces in the selected site, in accordance with its dynamic spectrum management capacity.

RFID applied to vehicular identification and the failed tag detection

Radio Frequency Identification System, a wireless communication system, recently it is applied to vehicular identification, nevertheless this system is not at all perfect for this application, tests in road show detection errors when the vehicle crosses the portal at high speed due to the number of correct readings is not totally successful. This tag/reader detection error is a limitation of the system applied to vehicular identification, since if the vehicle has been stolen, probably it will be running at very high speed to avoid be detected. In order to propose possible solutions, the focus of the work is to analyze the receiver section of the system and find the origin of this situation.

Some considerations about RFID system performance applied to the vehicular identification

When the RFID Technology is applied to vehicular identification, the objective is to have all the motor vehicle information inside the memory tag, and actually, it is limited to owner name, license, fines, etc. So, the focus of this work is to present some results of the experimental tests and measurements taken in the field and in the electromagnetic compatibility laboratory, from that, hint some parameters that should be readjusted when the application considers not only text information.