RF Module Research Articles

Analyzing the BER and optical fiber length performances in OFDM RoF links

Radio over fiber (RoF) can be assessed as a system of most convenient combination of optical fiber and radio signals. The technique of orthogonal frequency division multiplexing (OFDM) considers as a data distribution over a huge number of carriers having spaced from each other with specific frequencies at overlap bands. Hence incorporates OFDM with the optical fiber, OFDM-RoF system can be increased the modulation RF access capacity besides high-speed data transmission, it considers a broadband communication trend of the current and future applications specifically for 5G mobile. The optical network scenarios of various RF can be model with optisystem software, and OFDM in addition to use a section of the orthogonal multiplex frequency of 16-quadrature amplitude modulation (QAM) RF modulating signal. In the optical domain, Mach-Zehnder modulator (MZM) optical modulators are used to carry out different results with different fiber lengths. An OFDM-RoF wireless communication system considers as advanced data rate transmission achievement by minimum delays. The essential goal of this paper is for identifying the minimum bit error rate (BER) for the 16-QAM modulation with varying fiber length. The OFDM-RoF system can be able for realizing a fiber length 100 km with a restricted decreasing in the received power so that the constellation noise is became greater despite of applying electrical amplification and optical amplification.

Y(Luminance)-Based Modulation for Visual-MIMO

In color-space-based Visual-MIMO (Multi-Input Multi-Output), which means the communication between the LED array (LEA) and the camera, we have fixed the luminance (Y) to maintain the same color intensity. In this paper, we propose a method to use Y as a carrier of Visual-MIMO corresponding to the carrier of the RF communication. The key of the proposed method is to make Y act as a carrier as in the RF modulation and to recover the information through the adjustment of the receiver dynamic range and the circular Hough transform at the receiving end.

Women’s Safety and Tracking System with GSM AND GPS

Abstract: This paper aims at providing reliable and robust safety device that notifaies police in the area and family whenever the user sense crisis .In today’s world the life has become untroubled and comfortable due to the connectivity technologies so in this paper we have developed system that uses these technologies for the safety proposes of women .We have used the GPS sensor to track the current location of the user and GSM module to send the location to the authorities via text message .An RF Module TX and RX is also added to make the control circuitry compact. Keywords: Women’s Safety, Safety, GSM, GPS, Arduino, RF module.

Ultra simple low-power RF signal detection based on an optoelectronic feedback DFB laser.

An ultra simple and low cost method to detect low-power RF signal is proposed and experimentally demonstrated based on optoelectronic feedback DFB semiconductor laser. To our knowledge, according to public reports, this is the simplest photonics-assisted method which avoids using high sensitive optical modulators and narrow bandwidth optical filters. The RF signal, which matches the oscillation mode at the relaxation oscillation peak of the DFB laser, is amplified based on optoelectronic feedback. The RF signal from 1 to 4.5 GHz can be detected by adjusting the frequency of relaxation oscillation which is related to the laser bias current. The system provides a maximum gain of 15 dB for the low-power RF signal. The sensitivity of the system can reach up to as high as -97 dBm. Considering the real application of the detection system, the properties like dynamic range, resistance to large signals and performance for detecting modulated RF signal are also investigated.

Self-oscillating optical frequency comb generation based on the gain-switching dual-tone semiconductor laser

A novel method to generate the optical frequency comb (OFC) based on the gain-switching integrated semiconductor laser is proposed in this paper. In the system, by modulating the core device, i.e., dual-tone monolithic integrated semiconductor laser (DT-MISL), which is biased appropriately, with an enough large amplitude RF signal, it would be pushed into the gain-switching state and thus various OFCs with distinct comb lines can be generated. The superior advantage here is that the RF modulation signal is offered by the local oscillator, which can be originally generated after the photodetector based on the DT-MISL itself. In this case, no additional external microwave driver is required and thus the OFC generator is fully self-oscillating. To my best of knowledge, it is the first try based on the integrated laser source under the gain-switching state. Compared to other discrete systems, this compact structure is potential to develop for photonic integration. In the experiment, one discernible OFC with 114.448-GHz bandwidth and 17 comb lines within 10-dB amplitude variation is obtained, indicating the feasibility of this scheme. In addition, the tunability and the application of the OFCs in the generation of the multi-carrier signals are discussed at last.© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Study of the Third-Order Parametric Resonance Induced by RF Modulation

Study of the Third-Order Parametric Resonance Induced by RF Modulation

Electro-optic polymer and silicon nitride hybrid spatial light modulators based on a metasurface.

Spatial light modulators (SLMs) are important for various applications in photonics, such as near-infrared imaging, beam steering and optical communication. After decades of advances, current commercial devices are typically limited to kilohertz modulating speeds. To realize higher operating speeds, an electro-optic (EO) polymer and silicon nitride hybrid SLM has been demonstrated in this work. We utilize a specially designed metasurface to support a relatively high quality resonance and simultaneously confine most of the incident light in the active EO polymer layer. Combing with the high EO coefficient of the polymer, a clear modulation at 10 MHz with a driving voltage of Vp-p=±10 V has been observed in the proof-of-concept device. Our first-generation device leaves vast room for further improvement and may open an attractive route towards compact SLM with an RF modulation higher than 100 GHz.

Smart Helmet an Aid to Save Rider by Using Microcontroller

A smart helmet is a type of protective headgear used by the rider which makes bike driving safer than before. To Provide safety for the rider, the rider has to wear the helmet. By using advanced features like alcohol detection, accident identification, location tracking, fall detection. It is a hands free device. This is not only a smart helmet but also a feature of a smart bike. It is compulsory to wear the helmet, without which the ignition switch cannot turn ON. An RF Module is used as an wireless link for communication between receiver and transmitter. The ignition gets locked automatically when the rider is drunk , and sends a message to the registered number with his current location. If accident occurs it will send a message through GSM along with location with the help of GPS module. The distinctive utility of project is fall detection; if the rider falls down from the bike it sends a message to the registered mobile number.

Intelligent speed breaker system design for vehicles using Internet of Things

Bad visibility conditions which occur due to fog in winters or night time driving are the major causes of road accidents in India. The principal cause for such accidents is the unintentional ignorance of speed breakers which may be due to the driver not being able to detect them or may be due to over speeding of vehicles. This paper brings an idea of an intelligent speed breaker system that helps in detecting speed breakers well in time so that such accidents can be avoided. This system makes use of a RF module that warns the person who is driving about the existence of a speed breaker in proximity, with this it assists in automatically reducing the vehicle’s speed if no action is taken by the driver in time. Through Internet of Things (IoT), GPS Location (latitude & longitude) of speed breaker can be sent to cloud using GPS and stored on cloud to use it for future to avoid mishaps.

Obtaining of carbon nanoparticles in pulsed modulated RF discharge plasma

Carbon nanoparticles were synthesized using a 13.56 MHz RF discharge plasma in pulsed mode to control the size of the nanoparticles. An Ar/CH4 gas mixture was injected into the chamber to create capacitive coupled plasma medium, the main part of which is an electrode connected to the RF generator and a grounded electrode arranged in parallel. The synthesis experiments were carried out at room temperature and under the following conditions: pressure in the working chamber 0.99 Torr; concentration of Ar(96%)+CH4(4%) gas mixture; synthesis time 5 seconds; at discharge power 10 W. The frequency of the RF discharge plasma pulse during modulation was varied from 10 Hz to 10 kHz, also the duty-cycle was 50% for each performed experiment. Experimental observations have revealed that the size of carbon nanoparticles increases with the frequency of the pulse signal. It has also been determined that by using a frequency of the modulated pulsed RF signal it is possible to control the size of carbon nanoparticles in the range of 40-70 nm. The synthesized nanoparticles were collected directly on a copper mesh for TEM microscopy, which was placed on the surface of the bottom electrode. TEM image analysis showed two types of nanoparticles, some of which are an agglomerate of nanoparticles with an amorphous structure, while the others are nanometer-sized with crystalline structures.

Optimization and visualization of phase modulation with filtered and amplified maximal-length sequence for SBS suppression in a short fiber system: a theoretical treatment.

We use a model to investigate both the temporal and spectral characteristics of a signal lightwave which has been spectrally broadened through phase modulation with a maximal-length sequence (MLS), which is a common type of pseudo-random bit sequence. The enhancement of the stimulated Brillouin scattering (SBS) threshold of the modulated lightwave in a fiber system is evaluated by numerically simulating the coupled three-wave SBS interaction equations. We find that SBS can build up on a nanosecond-level time scale in a short fiber, which can reduce the SBS suppressing capability of MLS modulation waveforms with GHz-level clock rate, if the sub-sequence ("run") lengths with the same symbol (zero or one) of the MLS extend over several nanoseconds. To ensure the SBS buildup is perturbed and thus suppressed also during these long sub-sequences, we introduce a low-pass filter to average the signal over several bits so that the modulation waveform changes gradually even during long runs and amplify the RF modulation waveforms to the level required for sufficient spectral broadening and carrier suppression of the optical signal. We find that the SBS suppression depends non-monotonically on the parameters of the filtered and amplified MLS waveform such as pattern length, modulation depth, and the ratio of low-pass filter cutoff frequency to clock rate for maximum SBS mitigation. We optimize the SBS suppression through numerical simulations and discuss it in terms of the temporal and spectral characteristics of the lightwave and modulation waveform using derived analytical expressions and numerical simulations. The simulations indicate that the normalized SBS threshold reaches a maximum for a RMS modulation depth of 0.56π and a ratio of filter cutoff frequency to clock rate of 0.54 and that MLS9 is superior to other investigated patterns.

Broadband linearity enhancement method for a 1.3 GHz–2.5 GHz digitally-assisted oscillator in a 55-nm CMOS technology

At the L/S band, the digital array radars with digital beam-forming characteristics require a compact RF module for a plane array. Such an RF module would require a small-sized local clock generation to synchronize with the central distributed clock signal. This paper proposes a 0.04 mm2, broadband local clock generation for the RF module in digital array radar. In such a multi-band digital array radar, the linearity of the clock generator is a bottleneck. A linearity enhanced algorithm for switched-capacitor digitally-assisted oscillators is proposed in this paper. In this linearity enhancement technique, a calibration resistor array is used to improve frequency-tuning characteristics. The digitally-assisted oscillator has a highly linearized frequency tuning curve without demanding much more power and silicon area. A prototype is fabricated using a 55-nm CMOS process. From measurement, it has a frequency tuning range from 1.3 GHz to 2.5 GHz while occupying 225 × 180 μm2. The measured coarse bank tuning maximum DNL is 0.39 LSB, and the maximum INL is 4.64 LSB, which has been reduced to 43% of the other state-of-art work. The maximum power consumption is 15.8 mW from a 1.2 V supply voltage.

Conceptualization and Modelling the Functioning of The Networking Unit in Cyber Physical System for Smart Water Management

The paper concentrates on the networking part of Cyber physical system (CPS) perspective for water inflow and outflow details in the storage tanks. The system comprises the communication of customized existing water pipeline infrastructure in the storage tank interfaced with RF modules, Data Transfer Unit and aggregator. Finally in web server, the resulting information collected in the monitoring unit (RF module+ aggregator + Data transfer unit) will be displayed. In this paper, we focus in detail on communication between RF module, aggregator and DTU unit. This helps us to find out when water is most needed

Structural Design and Thermodynamic Analysis of a Missile Borne RF Module

The volume, weight and heat dissipation resources of missile borne SAR seeker are seriously limited, and the working environment is extremely harsh. Therefore, more stringent requirements are put forward on the structural design and thermal design of the electronic module on the missile borne SAR seeker. In this paper, the modular structure design and passive thermal control of a missile borne RF module are studied. In order to improve the interchangeability of products and simplify the design, a universal RF module based on JVPX connector is designed in this paper. In view of the high-speed and high-temperature physical working environment of the SAR seeker, the structure of phase-change heat sink is adopted in the module, which solves the thermal control problem of short-term reliable operation of the heating chip on the module. Finally, the effectiveness of the passive heat dissipation is verified by simulation analysis.

Hybrid material integration in silicon photonic integrated circuits

Hybrid integration of III–V and ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits (PICs). Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs. Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths, higher linearity, lower optical loss integrated optical modulators on chip. In this paper, we review existing integration strategies of III–V materials and present a route towards hybrid integration of both III–V and ferroelectrics on the same chip. We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media, similar to approaches adopted to maximize optical overlap with the gain section, thereby reducing lasing thresholds for hybrid III–V integration with silicon PICs. Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.

IOT based Fire and Toxic Gas Extinguisher using RF Module

IOT based Fire and Toxic Gas Extinguisher using RF Module

Black phosphorus photoconductive terahertz antenna: 3D modeling and experimental reference comparison

This paper presents a 3D model of a terahertz photoconductive antenna (PCA) using black phosphorus, an emerging 2D anisotropic material, as the semiconductor layer. This work aims at understanding the potential of black phosphorus (BP) to advance the signal generation and bandwidth of conventional terahertz (THz) PCAs. The COMSOL Multiphysics package, based on the finite element method, is utilized to model the 3D BP PCA emitter using four modules: the frequency domain RF module to solve Maxwell’s equations, the semiconductor module to calculate the photocurrent, the heat transfer in solids module to calculate the temperature variations, and the transient RF module to calculate the THz radiated electric field pulse. The proposed 3D model is computationally intensive where the PCA device includes thin layers of thicknesses ranging from nano- to microscale. The symmetry of the configuration was exploited by applying the perfect electric and magnetic boundary conditions to reduce the computational domain to only one quarter of the device in the RF module. The results showed that the temperature variation due to the conduction of current induced by the bias voltage increased by only 0.162 K. In addition, the electromagnetic power dissipation in the semiconductor due to the femtosecond laser source showed an increase in temperature by 0.441 K. The results show that the temperature variations caused the peak of the photocurrent to increase by ∼ 3.4 % and ∼ 10 % , respectively, under a maximum bias voltage of 1 V and average laser power of 1 mW. While simulating the active area of the antenna provided accurate results for the optical and semiconductor responses, simulating the thermal effect on the photocurrent requires a larger computational domain to avoid false rise in temperature. Finally, the simulated THz signal generation electric field pulse exhibits a trend in increasing the bandwidth of the proposed BP PCA compared with the measured pulse of a reference commercial LT-GaAs PCA. Enhancing signal generation and bandwidth will improve THz imaging and spectroscopy for biomedical and material characterization applications.

Tuning plasma parameters to control reactive species fluxes to substrates in the context of plasma catalysis

The key reactive plasma-produced gas phase species responsible for the enhanced conversion of chemicals in plasma catalysis compared to thermal catalysis have to date not been identified. This outstanding question is mainly due to the inherent large variety of plasma-produced species and the challenge of controlling and measuring the flux of each constituent of the cocktail of reactive species to a (catalytic) substrate. In this paper, we explore the possibility to control the dominant reactive species fluxes, relevant for plasma–catalysis, to a substrate in the effluent of an RF driven Ar–O2 plasma jet. The absolute species densities of the major reactive species (O, O2(a 1Δg), O3 and ions) were quantified by molecular beam mass spectrometry (MBMS) to assess the possibility of using treatment distance, O2 admixture concentration, plasma dissipated power, RF modulation frequency and duty cycle as well as the feed gas flow rate to alter the dominant species densities. Selected experimental results were also compared with a pseudo-1D plug flow model. The short-lived and long-lived species can be effectively separated by changing the treatment distance and the RF modulation frequency. Furthermore, adjusting the O2 admixture concentration enables to change the ratio of the O2(a 1Δg) and O3 density. The changes in the trend of ion and O flux were found to be very similar for nearly all investigated parameters. Nonetheless the gas flow rate was able to significantly change the ratio of the O and ion density in the plasma jet effluent. The impact of the surface-dependent loss probability and boundary layer reactions on the species flux to a substrate and how this qualitatively relates to the MBMS density measurements is further addressed.

IFMIF-DONES RF System

The IFMIF-DONES accelerator cavities require around 5.7 MW of continuous RF power at 175 MHz to deliver a 125 mA and 40 MeV deuteron beam at the lithium target. The IFMIF-DONES RF System is composed of 56 RF Stations able to provide up to 200 kW RF power at 175 MHz in CW, delivering a grand total of 7.4 MW.Such a massive system requires an ambitious approach to be able to comply with the accelerator requirements with a high efficiency and a high availability. The newest advancements in the field of RF systems for accelerators, which are already implemented independently in some facilities, are integrated for the first time in a single system from the early design phases. The result of this approach is the RF Station, which is a totally independent and compact RF module containing all the components needed to feed, control, and protect the accelerator cavities. The amplification technology chosen is the Laterally-Diffused Metal-Oxide Semiconductor (LDMOS) transistor, providing a good efficiency and high robustness. The proposed RF power combination of up to 160 transistors is based on resonant cavity combiner, allowing a single-step combination that highly reduces the losses with respect to more traditional corporate combining schemes. In this proposal, the RF generation relies on a fully digital Low-Level RF (LLRF) providing accurate amplitude/phase control and high flexibility to implement all the required functions for a proper cavity operation. The RF Station has been designed maximizing the modularity and the reliability. In order to achieve the required modularity, the LDMOS transistors have been grouped in Amplifier Modules (AMDs) containing four of them but keeping independent outputs. Furthermore, the AC/DC power converters have also been grouped in modules feeding a common DC bus. The RF Station will have redundant modules to be able to operate properly in any condition, even with some of them failed.This innovative proposal for the IFMIF-DONES RF System design and detailed information on the RF Stations architecture are presented in this paper.

Raspberry Pi based Multi-optional Wireless Wheelchair Control and Gesture Recognized Home Assist System

Smart Wheelchair is a controlled device designed with the help of the user command to have self-mobility. It reduces the human effort of the user and encourages wheelchair riding. In fact, it also provides an opportunity for physically impaired people to move from one location to another. The main work of this paper is to gain more information, to construct a wheelchair using Raspberry Pi and RF controller to solve the difficulties faced by the physically challenged person. The device is fitted with the RF module, GSM and GPS module, servo motor, wheelchair and the whole module is controlled by wheelchair. To achieve a desire movement, the user will provide input commands to control the wheelchair and it is interfaced by RF communication and voice command. Depending upon the user convenience either RF communication or voice command can be used. Solution has also been proposed during an emergency by using an alert system. The movements received and the hand gesture shown by the visually impaired are recognizedandcontrastedwiththemodelsstoredonthereceiver.Ifthetemplates suit the templates stored then the home appliances are managedaccordingly.