Efficiency enhancement of the reltron oscillator using four-grid asymmetrical RF interaction cavity

This paper presents a novel calibration method that equalizes the impulse responses of all the Radio Frequency (RF) modules of an antenna array system operating in Long-Term Evolution (LTE) evolved NodeB (eNB). The proposed technique utilizes the Zadoff-Chu (Z-C) sequence of the Primary Synchronization Signal (PSS) and Sounding Reference Signal (SRS) that are available in every LTE data frame for downlink and uplink, respectively, for estimating and compensating the differences in the impulse responses among the RF modules. The proposed calibration method is suitable for wide bandwidth signal environments of LTE because it equalizes the impulse response of each RF module, which is ultimately equivalent to compensate the phase and amplitude differences among RF modules for the entire frequency band. In addition, the proposed method is applicable while the target eNB is transmitting or receiving a data stream. From various experimental tests obtained from a test-bed implemented with 2 RF modules, it has been verified that the proposed method provides a reliable calibration for Release 10 Time Division Duplex (TDD) LTE signals. Phase errors after the calibration in our test-bed have been found to be about 2.418° and 2.983° for downlink and uplink, respectively.

Radio Frequency (RF) modules have been miniaturized to meet the demand for smaller and more enhanced handsets for wireless applications such as cellular phones. However, area for passive devices used in RF modules has made further miniaturization difficult. Passives embedded in substrates are now being studied intensively. In addition, circuit simulation technology has been developed that enables efficient designing of RF module circuits. Circuit designers, however, have limited database of organic substrates and embedded passives. Further, optimized thermal designs are required to prevent thermal resistance increase due to miniaturization of substrates. In this paper, we describe the high-frequency properties of the capacitors embedded in the organic substrates and present the equivalent circuit models of the embedded capacitors. We also present the thermal design of organic substrates applicable to RF modules.

Better Speech Recognition with Digital RF System in Study of Cochlear Implants

Radio frequency (RF) modules have been miniaturized rapidly due to the increasing demand for compact wireless applications such as cellular phones. RF modules involve many passive devices for decoupling, filtering, and matching impedance. RF designers have been seeking space for these passives. The technology of passive embedment in boards is one of the solutions to meet smaller device space requirement. In this paper, we describe the structure of and the process for printed wiring boards (PWBs) with embedded capacitors. The high frequency properties of the capacitors are introduced including the scattering parameters (S-parameters). In addition, their equivalent circuit models and simulation results are discussed.

The greatest favour of MIMO systems is that more satisfactory performance can be easily achieved without using additional transmit power or extension of the bandwidth. However, its main disadvantage is that additionally high-cost radio frequency (RF) modules are an essential necessity as multiple antennas are deployed. In general, RF modules include components like low noise amplifier (LNA), frequency down-converter and analog-to-digital converter (ADC). In an effort to reduce the cost associated with the multiple RF modules, antenna selection techniques can be used to employ a smaller number of RF modules than the number of transmit antennas. This paper gives the performance evaluation of various antenna selection techniques to improve the channel capacity in MIMO systems.

Short dense electron bunches are attractive from the viewpoint to use them for the implementation of powerful and compact radiation source based on the spontaneous mechanism of radiation. The regime of spontaneous radiation is realized, when the bunch phase size is smaller than 2π. Modern photo-injectors insure formation of mildly relativistic dense electron bunches with duration less than 1 ps. Such bunches are “ready” to radiate waves at terahertz frequencies in the spontaneous regime. However, the repulsion of particles caused by a strong Coulomb field inside the dense electron bunch strictly limits the duration of the radiation process due to the increase in the bunch length. We propose two mechanism of cyclotron radiation to solve this problem. The first one is the regime of group synchronism of particles with the radiated wave; in this case compensation of Coulomb repulsion in the phase space takes place. The second proposed solution is to use compression of bunch by radiated electromagnetic fields.

Give water to crops that is usually called as irrigation is one of the most important activities in farming system. Because water determine the crops growth and development, it should be available sufficiently inside the planting media. Recently, such control technology for crops irrigation has been developed though its application for such drip irrigation is still limited in small cultivated area. For extensive crop cultivation areas such as plantations, it needs a strategy to apply the technology in large cultivated area. We propose a model that is called as a smart irrigation systems (SIS). In the model, the large cultivated area is divided into several plots, where each plot has an independently automatic irrigation system. In order to be easily managed, each irrigation system in each plot can communicate to others and all information should be collected in a data server that is connected to cloud system. Since that common plantation area has limitation of communication lines, we propose a wireless sensor network (WSN) based on a radio frequency (RF) communication to connect all automatic irrigation systems. This paper focuses on designing a WSN prototype based on a radio frequency (RF) module to develop a smart drip irrigation system for large cultivated land. The WSN is designed from a master node functioned as coordinator and three slave nodes. The master and slave nodes are equipped with an RF module with a 2.4GHz frequency for communication. After construction, the WSN prototype with star topology is then tested for its ability, especially for transmitting data from slave to master and vice versa. The prototype has been tested with varied distance of 50 m, 100 m and 150 m between master and slave in a tree-blocked open space. Based on the data losses, the prototype has a good performance if the distances is less than 100 m.

This paper presents the design concept and experimental results about small size radio frequency (RF) module for 5GHz wireless local area network (WLAN). Functions of the RF module include from base band input/output to antenna switch. The size is 20mm × 15mm × 3mm and that is minimum size in modules with same functions as far as the authors get to know. For the purpose of small size and low cost, generally known technologies are used. They are multi chip module on laminated-base dielectric substrate (MCM-L) technology, interconnection of each layer using build-up technology, flip chip technology and ball grid array (BGA) technology. Parts and ICs are on both sides of the RF module's substrate and are vertically connected in the substrate. In order to ensure electrical performance at 5GHz frequency band in the high-density package, transmission line characteristics in the substrate and BGA characteristic are simulated by 3 dimensional (3D) electromagnetic (EM) software. The fabricated RF module is evaluated using the test set up for 5GHz WLAN application and the result is shown.

This paper presents the design concept and experimental results about small size radio frequency (RF) module for 5 GHz wireless local area network (WLAN). Functions of the RF module include from base band input/output to antenna switch. The size is 20 mm/spl times/15 mm/spl times/3 mm and that is minimum size in modules with same functions as far as the authors get to know. For the purpose of small size and low cost, generally known technologies are used. They are multi chip module on laminated-base dielectric substrate (MCM-L) technology, interconnection of each layer using build-up technology, flip chip technology and ball grid array (BGA) technology. Parts and ICs are on both sides of the RF module's substrate and are vertically connected in the substrate. In order to ensure electrical performance at 5 GHz frequency band in the high-density package, transmission line characteristics in the substrate and BGA characteristic are simulated by 3 dimensional (3D) electromagnetic (EM) software. The fabricated RF module is evaluated using the test set up for 5 GHz WLAN application and the result is shown.

A conventional radio frequency (RF) modulator with phase locked loop (PLL) has disadvantages in modulated specification and complicated systems. With the fast development of direct digital synthesis (DDS), DDS can be incorporated into the RF modulator, which results in flexible changing parameters and adding digital filters. However, the DDS modulator also causes some problems such as low output frequency and worse spurs. This paper discusses the results of RF digital modulation combining DDS with PLL and analyzes its modulator character and output spectrum character for ideal conditions. As a result, the RF output character in the loop band width is decided by DDS, and out of the loop band width is decided by a voltage controlled oscillator (VCO). The spurs of the DDS output can be filtered out and thus a good modulated signal spectrum can be achieved. Experimental results are presented. By combination of DDS with PLL, an RF digital modulator with good performance and low cost can be obtained.

In this paper, the design and the features of the Radio frequency (RF) module which is part of a novel Ka-band FMCW SAR system calibrator for both satellite and airborne prototypes is presented. According to controller instructions, this RF module which composed switch array has a function of RF link switching. At the same time, every indexes of RF link meet to calibration mode requirements for radar system. A prototype of the calibrator has been fabricated. The isolation of each channel is above 40dB over the specified operation frequency of 35.4GHz to 36.1GHz. In this scheme, closing the amplifier power and using isolator is effective measure to improve isolation. In this module, a serious problem of flat gain and stability is unpredictable since manufactures cannot provide detailed MMW component data due to bad consistency. To solve this problem, unpredictable flat gain and stability of output signal due to operating temperature between −20 and +45°C is examined both experimentally and theoretically. The developed calibrator features low cost, good flat gain and good stability of output signal. And it has been applied in a FMCW SAR imaging System.

This project has reviewed and implemented an internet of things (IoT) based indoor mobile robot. The robot is used for the housekeeping service through wireless fidelity (Wi-Fi) and called as “smart housekeeper”. The aim of the project is to implement IoT technology for housekeeping robot working as smart. The robot is equipped with wheel structure, camera holding structure and arm lifting machinery. It applies ATmega32 as the main controller and Wi-Fi module is used for communicating with it. An android phone is used as robot’s head. People can operate the robot through web page by another android phone from any place at any time. All the operations can perform from any place at any time using the web page and the radio frequency (RF) module. It can perform lamp and fan switching i.e. on/off, robot movement as forward, backward, left and right, arm lifting for floor duster, floor cleaning, and real-time video transmission through camera or smart phone. The experimental result shows that all the functions work properly. Keywords : IoT, RF module, robot movement, floor cleaning, indoor security Cite this Article Mohini Jogdand, Aparna Shinde, Kamal Jadhav. Review of IoT Based Smart Housekeeping Robot. Recent Trends in Electronics & Communication Systems . 2018; 5(1): 1–6p.

Several different mechanisms of compression of dense electron bunches in self fields are described. It is shown that the spontaneous radiation from a short (shorter than the radiation wavelength) electron bunch can result in a significant axial compression of the bunch under effect of the rf field of the radiated wave. This radiative self-compression can be provided in regimes of both cyclotron and undulator emission. Self-compression in the case of the “negative-mass” regime of the electron motion in an undulator of a special type is also described.

Considering the problem of miss reference database for previous patient’s data and miss interconnection between the medical environment units includes the physician, pharmacy, laboratory, etc… This paper aims to provide an interconnection between the medical environment units and physiological data which describe the conditions of his/her health to provide an important monitoring for the patient veracity. The proposed system consists of two main parts: data entry and querying system and wireless monitoring and acquisition system. The first part is a desktop application with database in the server. The second part consists of two wireless units: patient unit and hospital unit. The patient unit using the wireless sensors which collect the physiological parameter which are (temperature, blood pressure, heartbeat, and oxygen saturation) and forward it to the hospital unit through the Radio Frequency (RF) module, The hospital unit receives the physiological data from the patient unit through the RF module and then the hospital server updates the database by the physiological data which is considered as connecting point between the system parts. The experiential tests of the system were applied to insure the accuracy and integrated linking between the medical environment and patient data. In addition, using this system will help the doctor continuously monitors the physiological signals of patients in real-time. The proposed system was developed simulated and successfully verified. The collected data, using such system, could be useful for further bio-statistical analysis.

Electronic handsets have been rapidly miniaturized in form factor and developed with highly integrated functions, more complexity, and significantly improved performance. Within high density radio frequency (RF) modules, electromagnetic interference (EMI) issues such as unwanted cross-talk among the RF modules in mobile devices, cause electrical performance shifts, and make the modules more susceptible to electromagnetic compatibility (EMC) failures. All of these have raised considerable and critical challenges to RF design, which lead to a greater number of design iterations, prolonged design cycle times, and additional costs in a highly competitive market place. EMC has to be addressed during RF module design and package assembly by minimizing EMI radiation, reducing coupling paths, designing proper shielding, and grounding. The principle of EMI shielding is known as Faraday cage. This paper presents an overview of package level EMI shielding, where a metal layer is applied to partially or completely enclose a package in order to reduce the amount of EMI energy escaping into the external environment and also limit the EMI radiation that can penetrate into the package. Various EMI shielding techniques are compared and contrasted in terms of materials, process complexity, manufacturability, cost and EMI shielding effectiveness. Near-field EMI measurement/characterization is used to precisely capture EMI emission from device to system level or vice versa. The electromagnetic modeling methodology is used to pinpoint the root causes of unwanted EMI radiation on the module level.