RF Communication Research Articles

CTA Telescopes as Deep-Space Lasercom Ground Receivers

The amount of scientific data to be transmitted from deep-space probes is very limited due to RF-communications constraints. Free-space optical communication can alleviate this bottleneck, increasing data rate while reducing weight, mass and power of communication onboard equipment. Nevertheless, optimizing the power delivery from spacecraft to Earth is needed. In RF communications, the strategy has been to increase the aperture of ground terminals. Free-space optical communications can also follow it, as they share the limitation of low power received on Earth. As the cost of big telescopes increases exponentially with aperture, new ideas are required to maximize the aperture-to-cost ratio. This work explores the feasibility of using telescopes of the future Cherenkov Telescope Array as optical-communication ground stations. Ground-based gamma-ray astronomy has the same power limitation, hence Cherenkov telescopes are designed to maximize receiver's aperture with minimum cost and some relaxed requirements. Both critical issues of the reutilization and possible adaptations of the telescopes to optimize them for communications, and telescopes simulations and numerical computations of several link budgets applied to worst-case scenarios are discussed, concluding that the proposal is technically feasible and would bring important cost reductions and performance improvements compared to current designs for deepspace optical ground stations.

Optimal location of RFID reader antennas in a three dimensional space

Radio frequency identification (RFID) is a technology most commonly used for the tracking and identification of objects. Optimally implementing RFID is challenging, especially in supply chain management where the use of passive tags is more common. Challenges in RFID implementation include, costs, standardization, privacy, performance, reliability and a need for greater collaboration. Systems integration will be expensive too in most current systems. Due to the nature of RF communications, many RFID systems involve multiple readers. Therefore, determining the number and position of reader antennas has a significant effect on success of the deployment. In this paper, we propose two optimization models and a GRASP metaheuristic that consider the effect of the orientation of antennas, the type of material to identify, and the interference from obstacles in a three-dimensional warehouse. The solution gives the minimal number of readers along with their positions for 100 % coverage of the tagged items.

Towards the Realization of Graphene Based Flexible Radio Frequency Receiver

We report on our progress and development of high speed flexible graphene field effect transistors (GFETs) with high electron and hole mobilities (~3000 cm2/V·s), and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator) and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM) radio receiver operating at 2.4 GHz.

Health Monitoring System Based on Intra-Body Communication

This paper presents a model of a Body Area Network (BAN) health monitoring system based on Intra-Body Communication. Intra-body Communication (IBC) is a communication technique that uses the human body as a medium for electrical signal communication. One of the visions in the health care industry is to provide autonomous and continuous self and the remote health monitoring system. This can be achieved via BAN, LAN and WAN integration. The BAN technology itself consists of short range data communication modules, sensors, controller and actuators. The information can be transmitted to the LAN and WAN via the RF technology such as Bluetooth, ZigBee and ANT. Although the implementations of RF communication have been successful, there are still limitations in term of power consumption, battery lifetime, interferences and signal attenuations. One of the solutions for Medical Body Area Network (MBANs) to overcome these issues is by using an IBC technique because it can operate at lower frequencies and power consumption compared to the existing techniques. The first objective is to design the IBC's transmitter and receiver modules using the off the shelf components. The specifications of the modules such as frequency, data rate, modulation and demodulation coding system were defined. The individual module were designed and tested separately. The modules was integrated as an IBC system and tested for functionality then was implemented on PCB. Next objective is to model and implement the digital parts of the transmitter and receiver modules on the Altera's FPGA board. The digital blocks were interfaced with the FPGA's on board modules and the discrete components. The signals that have been received from the transmitter were converted into a proper waveform and it can be viewed via external devices such as oscilloscope and Labview. The signals such as heartbeats or pulses can also be displayed on LCD. In conclusion, the IBC project presents medical health monitoring model that operates at the range of 21 MHz frequency and reduce the power consumption for a longer battery lifetime.

Underwater wireless communications and networks: theory and application: Part 1 [Guest Editorial

The Earth is a water planet, two-thirds of which is covered by water. With the rapid developments in technology, underwater communications has become a fast growing field, with broad applications in commercial and military water based systems. The need for underwater wireless communications exists in applications such as remote control in the off-shore oil industry, pollution monitoring in environmental systems, collection of scientific data from ocean-bottom stations, disaster detection and early warning, national security and defense (intrusion detection and underwater surveillance), as well as new resource discovery. Thus, the research of new underwater wireless communication techniques has played the most important role in the exploration of oceans and other aquatic environments. In contrast with terrestrial wireless radio communications, the communication channels in underwater wireless networks can be seriously affected by the marine environment, by noise, and by limited bandwidth and power resources, and by the harsh underwater ambient conditions. Hence, the underwater communication channel often exhibits severe attenuation, multipath effect, frequency dispersion, and constrained bandwidth and power resources, etc., which turn the underwater communication channel into one of the most complex and harsh wireless channels in nature. When facing these unique conditions in diverse underwater applications, many new challenges, which were not encountered in terrestrial wireless communications, are emerging in underwater acoustic, optical, and RF communications for future underwater wireless networks. Of these challenges, acoustic and optical are the most compelling, and somewhat complementary, owing to the potential for longer range and high bandwidth networked communications in sizeand power-constrained modems and unmanned systems.

Turbo equalization for single-carrier underwater acoustic communications

Recent research in underwater acoustic communications has taken advantage of MIMO technologies to achieve reliable communication with 10–100 times increase of data rate in comparison to traditional systems. The powerful turbo equalization and FEC coding techniques enable both single-carrier modulation and OFDM systems to combat triply selective UWA channels. This article reviews the time-domain and frequency-domain turbo equalizer schemes for MIMO SCM systems. Low-complexity techniques are presented with both turbo linear equalizers and turbo soft decision feedback equalizers in both the time and frequency domains. Although results are shown specifically for UWA channels, these turbo equalizer techniques are also suitable for terrestrial RF communication systems.

Interposers: A Central Generic Technology for IoT

Also sometimes referred to as 2.5D integration, interposers are now a true and important component of the “3D world” based on die stacking technologies. Considered as an intermediate step in the field of high density die stacking (memory on logic, logic on logic, etc) this technology is on the other hand fully generic to manufacture heterogeneous systems which will constitute the basic of IoT (sensor with simple logic, RF capabilities and even energy harvesting). This paper presents first a short overview of the core technologies needed in this field. The versatility of these technical blocks, allowing to efficiently manufacture a large variety of interposer based devices, is then demonstrated through different subsystems related to IoT: sensors, passives, energy harvesters, RF communication. Some recent achievements in smart systems based on interposers mixing together passive components, microsystems and RF functions are then presented, and more particularly a system dedicated to short range high bandwidth communication for wireless HDMI and a system for implanted medical applications. In both cases, the gain in surface area is particularly important, making such solutions highly attractive.

Hi Density QFN Packages and Modules Incorporating Windings for Inductors, Chokes and Antennae

A QFN (quad flat no-lead) package (Figure 1) is one of the many platforms for fabricating semiconductor related devices. Though not as small as die level packages such as bumped die (CSP-chip scale packaging), the QFN package is designed to minimize its footprint by eliminating the “gull wing” protrusion of metal leads beyond the main package body. When compared to leaded packages QFN packages also provide better thermal performance as well as the reduced size.Figure 1Top and bottom view of finished QFN packagesFigure 1. Top and bottom view of finished QFN packages A QFN can also integrate multiple die, inductors, passives and other components into “modular” solutions where the QFN footprint serves as a multi-function, stand-alone platform. This conceptualization saves board space and improves functionality in a smaller area. In wireless and RFID applications the second die might be a PA (power amplifier) or RF transmitter die. In other applications antennae and coils are incorporated as actual features of the die during design or added post processing as a subsequent metalized layer (which is a poor utilization of silicon real estate). But often times these windings end up as an external feature built into the PCB. These designs are functional and have been sold for years, but adding components and layers onto PC boards or die require additional processing, increase size and cycle time which translate into higher costs. A better process eliminates post processing on the die and reducing the number of extra components added to the QFN or module. An even better process would integrate functionality into the package itself and reduce the size of the finished product. While maintaining leadframe integrity, lead pitch can be reduced by more than 50% down to 175μm over standard QFNs enabling higher density and higher IO count by improving etch control. Controlled etch not only allows for higher density but provides the ability to add windings directly into the package further increasing functionality and versatility. These windings, with 10μm lines and 10um spacing available in various geometrical shapes, can be used for inductors or antennae allowing for energy harvesting and/or RF communications.

UBITag: A Ubiquitous Optical Wireless Tag for Identifying Objects in the Physical Space

In this paper, an infrastructure that enables the association of a unique identification (ID) number to objects in the physical world is proposed. The system consists of a small tag that can be attached to any object. The tag is powered optically and establishes an optical communication link with a Reader. The Reader device can write a unique ID in the tag memory and can also readout the number. Each ID is also stored in a cloud database, which allows for associations of other attributes to the tag. By removing the need for a battery, using optical instead of RF communication, and minimizing the need for storing much information besides a single number, the size requirements on the tag are significantly reduced. A larger scale prototype is developed and end-to-end operation of the infrastructure is demonstrated. Prototyping is comprised the optical tag with active photovoltaic area of $1.44\,\mathrm {mm}^2$ and dimension of 9.7 mm × 6.9 mm, a Reader that optically interrogates with tag through 9600 baud UART protocol, a two-columned debatable for TagID and TagInfo data maintenance and a mobile application. In the end, basic packaging requirements of the tags are discussed and custom spherical packages with 1.8-mm diameter are developed. In the future, it is possible to mass produce the tags at a very low cost and attach them to many physical objects in the environment—creating a bridge between the physical and the cyber worlds.

원격 제어 기능을 포함한 교육용 모바일 로봇 시스템의 설계 및 구현

This paper presents the design and implementation of the educational remote controlled robot system including remote sensing in the embedded environment. The design of sensing information processing, software design and template design mechanism for the programming practice are introduced. LPC1769 ∙제1저자 : 정중수 ∙교신저자 : 정광욱 ∙투고일 : 2015. 2. 13, 심사일 : 2015. 3. 18, 게재확정일 : 2015. 4. 21. * 국립안동대학교 공과대학 정보통신공학과 교수(Dept. of Information & Communication Engineering, Andong National University) ** 구미1대학 정보통신공학과 교수/(주)맨엔텔 대표이사(Dept. of Information & Communication Engineering, Kumi University / CEO of Co, Ltd) ※ “이 논문은 2013년도 안동대학교 특별연구비에 의하여 연구되었음” 34 Journal of The Korea Society of Computer and Information April 2015 using Cortex-M3 core as CPU, LPCXPRESSO as debugging environment, C language as firmware development language and FreeRTOS as OS are used in development environment. The control command is received via RF communication by the server and the robot system which is operated by driving the various sensors. The educational procedure is from robot demo operation program as hands-on practice and then compiling, loading of the basic robot operation program, already supplied. Thereafter the verification is checked by using the basic robot operation to allow demo operation such as hands-on-training procedure. The original protocol is designed via RF communication between server and robot system, and the satisfied performance result is presented by analyzing the robot sensing data processing. ▸

Ubiquitous 3D positioning systems by led-based visible light communications

Currently, LEDs are popularly employed in our daily life due to various advantages. LEDs can also be employed for wireless data communications (i.e., VLC). Based on these LED-VLC systems, we can obtain high-performance positioning systems beyond the performance of RF communications or global positioning systems. In this article, we present a brief overview of positioning approaches in VLC systems, and also propose a maximum likelihood approach for the positioning system. Currently, the main technologies employ triangulations or image sensors for positioning a receiver in VLC systems. The least squares method is popularly employed for triangulation approaches in various ways, and we enhance the positioning performance by employing an iterative maximum likelihood approach by adopting the least square solution as an initial guess. We show the optimality of the proposed approach based on sufficient SNR.

Optical communications using orbital angular momentum beams

Orbital angular momentum (OAM), which describes the “phase twist” (helical phase pattern) of light beams, has recently gained interest due to its potential applications in many diverse areas. Particularly promising is the use of OAM for optical communications since: (i) coaxially propagating OAM beams with different azimuthal OAM states are mutually orthogonal, (ii) inter-beam crosstalk can be minimized, and (iii) the beams can be efficiently multiplexed and demultiplexed. As a result, multiple OAM states could be used as different carriers for multiplexing and transmitting multiple data streams, thereby potentially increasing the system capacity. In this paper, we review recent progress in OAM beam generation/detection, multiplexing/demultiplexing, and its potential applications in different scenarios including free-space optical communications, fiber-optic communications, and RF communications. Technical challenges and perspectives of OAM beams are also discussed.

Autonomous Mobile Robot Navigation System

This project presents a metal detecting robot using RF communication with wireless audio and video transmission and it is designed and implemented with Atmel 89C51 MCU in embedded system domain. The robot is moved in particular direction using switches and the images are captured along with the audio and images are watched on the television .Experimental work has been carried out carefully. The result shows that higher efficiency is indeed achieved using the embedded system. The proposed method is verified to be highly beneficial for the security purpose and industrial purpose. The mine sensor worked at a constant speed without any problem despite its extension, meeting the specification required for the mine detection sensor. It contributed to the improvement of detection rate, while enhancing the operability as evidenced by completion of all the detection work as scheduled. The tests demonstrated that the robot would not pose any performance problem for installation of the mine detection sensor. On the other hand, however, the tests also clearly indicated areas where improvement, modification, specification change and additional features to the robot are required to serve better for the intended purpose. Valuable data and hints were obtained in connection with such issues as control method with the mine detection robot tilted, merits and drawbacks of mounting the sensor, cost, handling the cable between the robot and support vehicle, maintainability, serviceability and easiness of adjustments. These issues became identified as a result of our engineers conducting both the domestic tests and the overseas tests by themselves, and in this respect the findings were all the more practical.

Integrated Localized MicroCooling Using High-Displacement Piezoelectric Actuators

RF communication and radar systems present an extreme thermal management challenge. These systems are comprised of tightly packaged, high-power components requiring a controlled temperature to meet performance and reliability parameters. In these systems, there is little space available for macro-scale air flow or other traditional cooling methods. In addition, heat generating components are typically microscale semiconductor devices fabricated on integrated circuit substrates buried deeply within the system. Localized cooling using integrated microsystems may provide a solution to these thermal management issues. One approach is the integration of miniature synthetic air jets near the heat generating components. Synthetic jets are generated using oscillating piezoelectric actuators that force air through a small nozzle at high flow rates and in close proximity to the heat generating component. The resulting jets provide vorticity within the fluid, leading to enhanced mixing with the surrounding lower temperature environment and a subsequent increase in the heat transfer coefficient. The US Army AMRDEC has been developing and operating microactuator test beds, utilizing high-displacement actuator architectures, including THUNDER and Lightweight Piezo-Composite Actuator (LIPCA) approaches, to reduce actuator size while maintaining sufficient flow rates and vorticity. This investigation has modeled and fabricated potential high-displacement miniature actuators, as well as predicted and characterized resulting jet parameters and heat transfer coefficients utilizing these actuators. This paper will present actuator designs, fabrication process, and cooling results using these high-displacement piezoelectric actuators as the drive element.

Horizontal current bipolar transistor (HCBT) - a low-cost, high-performance flexible BiCMOS technology for RF communication applications

In an overview of Horizontal Current Bipolar Transistor (HCBT) technology, the state-of-the-art integrated silicon bipolar transistors are described which exhibit f T and f max of 51 GHz and 61 GHz and f T BV CEO product of 173 GHzV that are among the highest-performance implanted-base, silicon bipolar transistors. HBCT is integrated with CMOS in a considerably lower-cost fabrication sequence as compared to standard vertical-current bipolar transistors with only 2 or 3 additional masks and fewer process steps. Due to its specific structure, the charge sharing effect can be employed to increase BV CEO without sacrificing f T and f max . Moreover, the electric field can be engineered just by manipulating the lithography masks achieving the high-voltage HCBTs with breakdowns up to 36 V integrated in the same process flow with high-speed devices, i.e. at zero additional costs. Double-balanced active mixer circuit is designed and fabricated in HCBT technology. The maximum IIP3 of 17.7 dBm at mixer current of 9.2 mA and conversion gain of -5 dB are achieved. This article has been corrected. Link to the correction DOI:10.2298/FUEE1703429E

직렬 UART 통신 기반 rf 통신 시스템 구현

무선 모듈을 사용하여 무선 데이터를 mcu모듈과 PC와의 사이에 통신을 하고자 할때는 우선 PC를 기본으로하는 시리얼 통신을 PC자체적으로 구현한 후 구현된 프로그램을 사용하여 MCU와의 통신을 시행한다. PC자체적으로 시리얼 통신을 시행코자 할때는 RS-232C를 사용하여 데이터를 교환한다. 교환된 데이터를 rf모듈을 사용 UART기반 시리얼 통신 원격제어를 MCU를 사용하여 시행한다. MCU 인터페이스 원격제어가 실현되면 통신시스템이 구현된 것이다. Through MCU model, Radio Frequency communication is completed using universal asynchronous receiver and transmitter. The communicatin with PC and MCU is completed using RS-232 cable. At first interconnected communication with PC and MCU is necessary for RF communication because tha UART is based technique for RF communication. Program imbeded in microcontroller unit is ran during RF signal is transmitted to other RF module. Data connected with PC and MCU is transmitted between PC and MCU during PC and MCU is connected.

Wireless gas detection with a smartphone via rf communication.

Chemical sensing is of critical importance to human health, safety, and security, yet it is not broadly implemented because existing sensors often require trained personnel, expensive and bulky equipment, and have large power requirements. This study reports the development of a smartphone-based sensing strategy that employs chemiresponsive nanomaterials integrated into the circuitry of commercial near-field communication tags to achieve non-line-of-sight, portable, and inexpensive detection and discrimination of gas-phase chemicals (e.g., ammonia, hydrogen peroxide, cyclohexanone, and water) at part-per-thousand and part-per-million concentrations.

Printed single-chip UHF passive radio frequency identification tags with sensing capability

Two printed single-chip UHF radio frequency identification (RFID) tags compatible with EPC Gen 2 protocol capable of measuring temperature and relative humidity are presented. The UHF RFID chip SL900A, which includes an on-chip temperature sensor, is used on both tags to drive the relative humidity (RH) sensors and the RF communication. These tags have been fabricated on polyimide substrate (Kapton HN) which presents a well known humidity dependence. Printed RH sensors consist of an array of 12 serpentine electrodes fabricated by inkjet printing and an array of 6 screen printed interdigitated electrodes, respectively, to achieve a capacitance of around 35pF far from the capacitive parasites present in the structure. Both tags are able to provide temperature and relative humidity environmental parameters in digital form answering to the inquiries of a RFID reader in a passive energy mode (without batteries). With very low thermal drifts, below 0.05%RH/°C, a RH range of 30% is covered by both tag with sensitivities of 100fF/RH% for the inkjetted serpentine structure and 54fF/RH% for the screen-printed one. Therefore, we propose passive RFID tags with a single silicon chip providing a cost-effective solution to monitor environmental conditions based on printing technologies.

Editoral: Special Issue on Photonic and RF Communications Systems

Editoral: Special Issue on Photonic and RF Communications Systems

The Development of Underground Personnel Data Terminal Based on RSSI Location

Based on the emerging ZigBee wireless RF communication technology, this paper presents the design of a miner information collection terminal. The entire system is designed around the CC2431 SoC hardware circuit, through ZigBee networking, to achieve the location of underground environment and miner vital signs data acquisition, so that it can provide effective help to quickly carry out rescue work.