We present a photonically-excited antenna array at E-band for scanning by beam switching in wireless links. First, we discuss the proposed technique applied to photonic-enabled (sub)millimeter-wave ...transmitters. Next, we present our implementation; it consists of two sub-arrays of stacked patches as primary feeds of a Polytetrafluoroethylene (PTFE) lens, with one photodiode feeding each sub-array. To validate the assembly, the return loss and radiation patterns have been measured for one of the sub-arrays excited with a coplanar probe. In turn, the lens illuminated by one of the sub-arrays yields a directivity of 27 dBi. The radiation patterns measured for the transmitter module (including the lens) are in very good agreement with full-wave simulations, and they show that excitation of one of either sub-arrays allows beam switching between <inline-formula><tex-math notation="LaTeX">\pm 2.7^\circ</tex-math></inline-formula> with a beam crossover at <inline-formula><tex-math notation="LaTeX">-3\, \mathrm{dB}</tex-math></inline-formula>. Finally, we have tested the transmitter in a 0.6 m wireless link. Depending on the position of the detector and on which sub-array is excited, we have accomplished 5 Gbps transmission for on-off-keying modulation and direct detection (BER <inline-formula><tex-math notation="LaTeX">=10^{-11}</tex-math></inline-formula>). The system constitutes an initial proof of photonic-assisted beam switching for mm-wave transmitters enabling broadband operation with a directive and switchable beam.
A novel feeding method for a dielectric resonator array antenna is introduced. Unlike in a corporate feed network, power dividers or quarter-wave transformers are not needed in the new feeding scheme ...as the design is based on the standing-wave concept. Consequently, the feed network is greatly simplified, and undesired spurious radiation in the feeding network is minimized. The simulated and measured results are in good agreement. A 3-D printer is utilized where the entire array structure is fabricated as a single piece with a dielectric material of polylactic acid. The 3-D printer provides a cost-efficient, simple, and rapid manufacturing process.
Quantum transducers are key components for hybrid quantum networks, enabling the transfer of quantum states between microwave and optical photons. In the quantum community, many efforts have focused ...on creating and verifying the entanglement between microwave and optical fields in systems that typically operate at temperatures in the millikelvin range. Our goal is to develop an integrated microwave optical entanglement device based on a lithium niobate whispering gallery mode resonator (WGMR). To investigate the feasibility of developing such an integrated device, first, a passive photonic integrated circuit (PIC) was designed, fabricated, and characterized. The PIC was developed on a thin-film lithium niobate (TFLN) on an insulator platform, and it includes eight ring resonators and four asymmetric Mach–Zehnder interferometers. This paper presents the design and operational principles of the integrated device for microwave–optical entanglement, as well as the results of the characterization of the passive PIC.
Multifrequency microstrip patch antennas partially filled with left-handed (LH) structures are presented. The presence of LH structures also enables miniaturized antennas. Thus, multifrequency, ...dual-mode, and miniaturized antennas based on single patches partially filled with LH structures have been obtained. First, multiple operation over several band frequencies is proven from the transmission-line theory. Then, an implementation based on microstrip patches partially filled with mushroom-like structures is proposed. Two multifrequency patch antennas have been designed, built, and measured. The first one shows two dipolar (patch like) modes at 1.06 GHz and 2.16 GHz and a monopolar mode (null at broadside) at 1.45 GHz. The ratio between the resonant frequencies of both dipolar modes can be arbitrarily chosen (by means of a proper design of the patch and the LH structures) and, in this case, is 2.04. The second antenna is designed to work at closer frequencies. In this case, the frequency ratio is dramatically reduced to produce a dual dipolar antenna working at 1.81 GHz and 2.20 GHz (giving a ratio of 1.21).
This paper presents a fast calibration method to determine the transfer function for spatial correspondences in image transmission devices with Incoherent Optical Fiber Bundles (IOFBs), by performing ...a scan of the input, using differential patterns generated from a Gray code (Differential Gray-Code Space Encoding, DGSE). The results demonstrate that this technique provides a noticeable reduction in processing time and better quality of the reconstructed image compared to other, previously employed techniques, such as point or fringe scanning, or even other known space encoding techniques.
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In this paper, the most adequate architecture to implement dual frequency amplifiers is shown. Composite Right/Left Hand (CRLH) and Extended Composite Right/Left Hand (ECRLH) transmission lines are ...studied and evaluated to find the most suitable structure for dual band power amplifiers. As an example, the performance of a class CE amplifier, working in TETRA and GSM frequency bands, is compared with simulations and measurement, showing good agreement.
This paper presents a full duplex active RF identification system with arbitrary values for any of the two frequencies in the different radio links. First, the antennas proposed in this paper are ...based on linearly polarized self-diplexed patch antennas working in a full-duplex way at 2.45 GHz for the reader-transponder (or tag) link and at a lower variable frequency (1.7 GHz) for the transponder-reader link reducing the propagation losses for the most critical link. Secondly, in order to reduce the multipath losses, antennas with circular polarizations for the reader and linear polarization for the transponder have been designed for the corresponding radio links. Patch antennas partially filled with metamaterial cells have offered the possibility of achieving multifrequency performance with two dipolar radiation modes, one due to the patch and the other to the metamaterial cells. This fact makes it possible to obtain high isolation levels between different ports. In addition, the inclusion of coupled or slot lines to feed the antenna has increased this isolation level. Finally, the diplexing level has been increased by including some filtering lines with metamaterial particles at the input of the feeding line. This approach avoids using an external filter or diplexer.
Clinical evaluation of the patellar reflex is one of the most frequent diagnostic methods used by physicians and medical specialists. However, this test is usually elicited and diagnosed manually. In ...this work, we develop a device specifically designed to induce the patellar reflex and measure the angle and angular velocity of the leg during the course of the reflex test. We have recorded the response of 106 volunteers with the aim of finding a recognizable pattern in the responses that can allow us to classify each reflex according to the scale of the National Institute of Neurological Disorders and Stroke (NINDS). In order to elicit the patellar reflex, a hammer is attached to a specially designed pendulum, with a controlled impact force. All volunteer test subjects sit at a specific height, performing the Jendrassik maneuver during the test, and the medical staff evaluates the response in accordance with the NINDS scale. The data acquisition system is integrated by using a tapping sensor, an inertial measurement unit, a control unit, and a graphical user interface (GUI). The GUI displays the sensor behavior in real time. The sample rate is 5 kHz, and the control unit is configured for a continuous sample mode. The measured signals are processed and filtered to reduce high-frequency noise and digitally stored. After analyzing the signals, several domain-specific features are proposed to allow us to differentiate between various NINDS groups using machine learning classifiers. The results show that it is possible to automatically classify the patellar reflex into a NINDS scale using the proposed biomechanical measurements and features.
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Dengue (DEN) is an infectious disease caused by the DEN virus (DENV), which belongs to the Flavivirus genus in the family Flaviviridae. It has a (+) sense RNA genome and is mainly transmitted to ...humans by the vector mosquito Aedes aegypti. Dengue fever (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related virus serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). Epidemiological and evolutionary studies have indicated that host and viral factors are involved in determining disease outcome and have proved the importance of viral genotype in causing severe epidemics. Host immune status and mosquito vectorial capacity are also important influences on the severity of infection. Therefore, an understanding of the relationship between virus variants with altered amino acids and high pathogenicity will provide more information on the molecular epidemiology of DEN. Accordingly, knowledge of the DENV serotypes and genotypes circulating in the latest DEN outbreaks around the world, including Mexico, will contribute to understanding DEN infections.
1. We obtained 88 isolates of DENV, 27 from Oaxaca and 61 from Veracruz. 2. Of these 88 isolates, 16 were serotype 1; 62 serotype 2; 7 serotype 3; and 2 serotype 4. One isolate had 2 serotypes (DENV-2 and -1). 3. Partial nucleotide sequences of the genes encoding C- prM (14 sequences), the NS3 helicase domain (7 sequences), the NS5 S-adenosyl methionine transferase domain (7 sequences) and the RNA-dependent RNA polymerase (RdRp) domain (18 sequences) were obtained. Phylogenetic analysis showed that DENV-2 isolates belonged to the Asian/American genotype. In addition, the Asian/American genotype was divided into two clusters, one containing the isolates from 2001 and the other the isolates from 2005-2006 with high bootstrap support of 94%.
DENV-2 was the predominant serotype in the DF and DHF outbreak from 2005 to 2006 in Oaxaca State as well as in the 2006 outbreak in Veracruz State, with the Asian/American genotype prevalent in both states. Interestingly, DENV-1 and DENV-2 were the only serotypes related to DHF cases. In contrast, DENV-3 and DENV-4 were poorly represented according to epidemiological data reported in Mexico. We found that isoleucine was replaced by valine at residue 106 of protein C in the isolates from these 2005-2006 outbreaks and in those from the 1997, 1998 and 2001 outbreaks in the Caribbean islands. We suggested that this amino acid change may be used as a signature for isolates arising in the Caribbean islands and pertaining to the Asian/American genotype. Other amino acid changes are specific for the Asian/American, Asian and American strains.
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