RF Chip Research Articles

Non-Graded Base Si/Ge Heterojunction Transistor

<strong>Innovation of Heterojunction Bipolar Transistor (HBT) technology is a major game changer in wireless communication, power amplifiers and other major fields of electronics. HBTs play a vital role in extending the advantages of silicon bipolar transistors to significantly higher levels. Research on HBT is focused on reducing cost and improving reliability. These transistors have a wide range of applications namely, digital-to-analog converters, logarithmic amplifiers, RF chip sets for CDMA wireless communication systems, and power amplifiers for cellular communications. Our study focuses on utilizing the high mobility of pure Ge instead of often-used graded Ge base. Non-grtaded Ge base enhanses carrier transport which in turn increases the gain and cut-off frequency of the HBT. We have developed a high frequency, high current gain, high power gain and less noisy heterojunction bipolar transistor operating above 100GHz frequency. Lattice mismatch at emitter and collector junctions is compensated by inserting SiGe buffer layers. ATLAS TCAD - SILVACO software is used for modelling of this novel device.</strong>

Signal transmission and node deployment of a 2.4 GHz wireless sensor network: A case study in a persimmon orchard

The change of received signal strength index and packet loss rate under 2.4 GHz radio communication in a persimmon orchard in flowering phase was investigated. Texas CC2530 RF chip and the TinyOS system based WSN nodes were selected as instruments to conduct interwoven tests along a column of persimmon trees and different rows and columns of the orchard, and measure the receiving signal strength and packet loss rate which were in the three different heights from 0.80 m at the bottom of the canopy to 2.80 m at the top. In the tests, distance of each three trees was set as a tested distance, and there were eight tested distances in each row or column totally. Afterwards, all the obtained data underwent regression analysis. The results showed that when the transmitter and receiver were maintained at a fixed height, the received signal strength decreased, while the packet loss rate increased with the augment of tested distance. Furthermore, under the two situations where receiver was at the fringe of persimmon orchard and both transmitter and receiver were in the orchard, the models of signal strength attenuation affected by different factors along a row of persimmon tree were established and evaluated. Additionally, the curved surface graphs of different transceiver heights and different ranks of trees which were drawn by MATLAB software was able to reflect wireless signal transmission characteristics in persimmon orchard straightly.

(Micro)Metering with Microwaves: A Low-Cost, Low-Power, High-Precision Radar System

Over the last several years, short-range, noncontact microwave radar systems for industrial and medical applications have received significant attention for several reasons [1], [2]. First, today's RF chips are more efficient and smaller than comparable chips of a few years ago. Second, the high demand for new sensor systems in health-care, automotive, and industrial applications, especially as the field of smart factories emerges, has boosted development of ultralow-cost radar modules for the mass market [3], [4].

Design and Implementation of a RFID Reader/Router in RFID-WSN Hybrid System

In order to put Radio Frequency Identification (RFID) and Wireless Sensor Network (WSN) in a hybrid system, this paper presents the design and implementation of a RFID reader/router that can obtain information of both RFID tags and WSN sensor nodes and transmit the information through the WSN to the PC server. The RFID reader and WSN router are combined with both hardware and software. In hardware structure, CC2530 is used as micro controller and RF module for ZigBee wireless communication, and MF RC522 is used as reader RF chip. The software deals with both identity and sensing information and controls the routing. Experiment results show that the RFID reader/router achieves long distance identification, flexibility, scalability, and low cost. It also provides reliable and secured data transmission and broadens the communication range and application scope of RFID readers.

Design of Low Power Handheld Meter Reading Terminal Based on S3C6410 and CLRC632

To meet the requirements of handheld meter reading terminal for fast and accurate, low power consumption and low cost, a low power RFID handheld meter reading terminal based on S3C6410 is designed. Based on high-performance, low-power S3C6410 chip and CLRC632 RF chip to achieve non-contact RFID read and write operations, and supporting the design of the human-computer interaction module, power management module, read and write modules and other circuits. The factors such as the power consumption, the cost, the power supply stability, the security of the data transmission and Friendly human - computer interaction are considered to carry out the hardware and software design of handheld terminals. The experimental results show that the meter reading terminal has the characteristics of fast and accurate group copying, low power consumption and low cost, and has the popularization and application value.

Fractional-N phase-locked loop for split and direct automatic frequency control in A-GPS

ABSTRACTA low-power mixed-signal phase-locked loop (PLL) is modelled and designed for the DigRF interface between the RF chip and the modem chip. An assisted-GPS or A-GPS multi-standard system includes the DigRF interface and uses the split automatic frequency control (AFC) technique. The PLL circuitry uses the direct AFC technique and is based on the fractional-N architecture using a digital delta-sigma modulator along with a digital counter, fulfilling simple ultra-high-resolution AFC with robust digital circuitry and its timing. Relative to the output frequency, the measured AFC resolution or accuracy is <5 parts per billion (ppb) or on the order of a Hertz. The cycle-to-cycle rms jitter is <6 ps and the typical settling time is <30 μs. A spur reduction technique is adopted and implemented as well, demonstrating spur reduction without employing dithering. The proposed PLL includes a low-leakage phase-frequency detector, a low-drop-out regulator, power-on-reset circuitry and precharge circuitry. The PLL is implemented in a 90-nm CMOS process technology with 1.2 V single supply. The overall PLL draws about 1.1 mA from the supply.

4 × 56 Gb/s High Output Power Electroabsorption Modulated Laser Array With up to 7 km Fiber Transmission in L-Band

We present a novel array of electroabsorption modulated lasers as compact and low-cost single-chip solution for future 200 Gb/s transmitters. The array is designed for high optical output power with semiconductor optical amplifiers at the front side of the chip. A common InGaAlAs-MQW active layer structure allows for simple and cost-effective monolithic integration. On chip RF transmission lines are implemented to bring all electrical contacts to the rear side of the array-chip which supports packaging with short wire bonds. The array operates at four different wavelengths spanning over 7.5 nm in the L-band. Uniformity of each wavelength channel is experimentally proven regarding modulation bandwidth >30 GHz, extinction ratio >7 dB, and output power up to 8 dBm. The influence of the semiconducting optical amplifiers on signal quality is investigated by back to back bit error ratio measurements. In transmission experiments over standard single mode fiber links, the array's performance at 4 × 56 GBd NRZ and 4 × 28 GBd PAM4 is demonstrated and the arrays capability for up to 7 km transmission in case of PAM4 signaling is shown.

Design of Intelligent Vehicle Monitoring System Based on ZigBee

In order to meet the needs of real-time positioning and remote dispatching of vehicle, this paper designs a ZigBee-based embedded vehicle terminal and the corresponding ZigBee-GPRS information communication network in hardware and software. With LPC2366 processor and CC2430 RF chip as core, the vehicle terminal acquires the vehicle‘s status in cycle, and completes the vehicle monitoring and scheduling by transmitting data to communication nodes by ZigBee and passing the data on to the monitoring center by GPRS. This vehicle terminal is characterized by small size, low energy consumption and ideal communication distance, which makes the monitoring center effectively monitor and schedule the vehicles.

Design of Wireless Sensor Network Bidirectional Nodes for Intelligent Monitoring System of Micro-irrigation in Litchi Orchards

Wireless sensor network (WSN) bidirectional nodes, including the sensing node and the solenoid valve control node, were developed for information collection and micro-irrigation monitoring system in a litchi orchard, aimed at improving the problem of wireless communication barriers and the micro-irrigation management efficiency. The sensing node was composed of an MCU8051, a CC2530 RF chip for communication, a RFX2401for amplification. This node is supposed to collect data from a DHT22 air temperature and humidity sensor, a GY-30 light intensity sensor and a TDR-3 soil moisture sensor. The control node includes an MCU8051, a CC2530 RF chip for communication, and peripheral drive circuits for adapting the bi-stable pulse solenoid valve. The application software and backstage management software were written with these two nodes as the hardware platform, based on ZStack agreement. The maximum effective bidirectional communication distance of the designed nodes reached 1205m in unoccupied regions and 122m in litchi orchards. Within a 30 min working cycle, it could be estimated that two 3.7 V battery with a rated capacity of 3000 mA•h can power the sensing node for time up to 500d. Test results in litchi orchards show that the average packet loss rate is 0.75%. The system was processing smoothly with the above nodes for information acquisition and controlling micro-irrigation in litchi orchards.

Design a WSN system for monitoring the safety of drinking water quality

For the application of drinking water safety monitoring, a sensor node and a gateway node which were suitable for setting up a Wireless Sensor Network (WSN) in water supply area were developed. The sensor node used an STM32F103 as the processing core, an A7139 RF chip and its peripheral circuits as the wireless communication module, and 4 ASI water quality electrodes including dissolved oxygen (DO), hydrogen ion exponent (pH), ammonia nitrogen and temperature as the sensing module. The gateway node used a GPRS module to upload network data to the server. A flooding routing protocol was designed for increasing the reliability of data transmission between sensor nodes. The results of the 100 days networking experiment indicated that the average PLR of network was 3.55%, which could meet the requirements for stable transmission of network data. In conclusion, the design of sensor node and GPRS gateway is suitable for effective monitoring of water quality of drinking water supply area.

A security-enhanced mutual authentication scheme with privacy protected in wireless sensor networks

In recent years, the debate on user privacy is becoming increasingly fierce. As wireless sensor networks (e.g.: electronic medical system and smart home systems) increasingly penetrate people’s lives, it is imperative to design an identity authentication scheme with user privacy protection for wireless sensor networks. At present, many researchers have given their user authentication schemes by using different methods for user privacy protection. Two factor authentication scheme is now considered a relatively high safety performance. In this paper, we analyze the two factor authentication scheme proposed by Nam et al., and find that the scheme still has defects. The most fatal problem is that the scheme does not provide sufficient protection for privacy in wireless sensor networks. Based on the work of Nam, we are a complement to the defects of the existing scheme. A random number is inserted into the user registration phase to change the identity of the user into a disguised identity and assign ECC key pairs to each sensor node, thus enhancing the security of the node authentication data. In formal analysis, we use BAN logic as our analysis tool to prove that our scheme achieves mutual authentication. Furthermore, we also give informal analysis for almost known attacks, the result shows that our proposed scheme could provide better security features. Finally, we implemented our authentication scheme on the RF chip CC2538, and measured the related execution time parameters. In order to obtain more security features, the proposed scheme is slightly higher than other schemes in terms of time complexity.

Energy Neutral Wireless Bolt for Safety Critical Fastening.

Thermoelectric generators (TEGs) are now capable of powering the abundant low power electronics from very small (just a few degrees Celsius) temperature gradients. This factor along with the continuously lowering cost and size of TEGs, has contributed to the growing number of miniaturized battery-free sensor modules powered by TEGs. In this article, we present the design of an ambient-powered wireless bolt for high-end electro-mechanical systems. The bolt is equipped with a temperature sensor and a low power RF chip powered from a TEG. A DC-DC converter interfacing the TEG with the RF chip is used to step-up the low TEG voltage. The work includes the characterizations of different TEGs and DC-DC converters to determine the optimal design based on the amount of power that can be generated from a TEG under different loads and at temperature gradients typical of industrial environments. A prototype system was implemented and the power consumption of this system under different conditions was also measured. Results demonstrate that the power generated by the TEG at very low temperature gradients is sufficient to guarantee continuous wireless monitoring of the critical fasteners in critical systems such as avionics, motorsport and aerospace.

Optimization and validation of thermal management for a RF front-end SiP based on rigid-flex substrate

This paper mainly presents a new 3D stacking RF System-in-Package (SiP) structure based on rigid-flex substrate for a micro base station, with 33 active chips integrated in a small package of 5cm×5.5cm×0.8cm. Total power consumption adds up to 20.1Watt. To address thermal management and testability difficulties of this RF SiP, a thermal test package is designed with the same package structure and assembly flow, only replacing active chips with thermal test dies (TTDs). Optimization and validation of thermal management for the thermal test package is conducted. Effects of the structure, chip power distribution, and ambient temperature aspects on the thermal performance are studied. Thermal vias designed in the organic substrate provide a direct heat dissipation path from TTDs to the top heatsink, which minimizes junction temperature gap of the top substrate from 31.2°C to 5.3°C, and enables junction temperatures of all the chips on the face to face structure to be well below 82°C. Chip power distribution optimization indicates placing high power RF parts on the top rigid substrate is a reasonable choice. The ambient temperature optimizes with forced air convection and cold-plate cooling method, both of which are effective methods to improve thermal performances especially for this micro base station application where environment temperature may reach more than 75°C. The thermal management validation is performed with a thermal test vehicle. Junction temperatures are compared between finite-volume-method (FVM) simulation and thermal measurement under the natural convection condition. The accordance of simulation and measurement validates this thermal test method. Junction temperatures of typical RF chips are all below 80°C, which shows the effectiveness of thermal management of this RF SiP.

Design of Tropical Flowers Environmental Parameters Wireless Monitoring System Based on MSP430

Considering the importance of real-time monitoring tropical flower environment parameters, the paper designs a wireless monitoring system based on MSP430F149 for tropical flower growing parameters. The proposed system uses sensor nodes to obtain data of temperature, humidity and light intensity, sink node to collect data from sensor nodes through wireless sensor network, and monitoring center to process data downloaded from the sink node through RS232 serial port. The node hardware platform is composed of a MSP430F149 processor, AM2306 and NHZD10AI sensors used to adopt temperature, humidity and light intensity data, and an nRF905 RF chip used to receive and send data. The node software, operated in IAR Embedded Workbench, adopts C Language to do node data collection and process, wireless transmission and serial port communication. The software of monitoring center develops in VB6.0, which can provide vivid and explicit real-time monitoring platform for flower farmers.

Application of Communication Technology in the Distributed Network Sensor Based on Radio Frequency Chip RF

In this paper, the work of transmission test field data to the terminal, the wireless data transmission capacity in order to test the wireless data transmission terminal objective and effective, the choice of the open area and factory two site, to test the receiving terminal in different condition, respectively in the experiment of the terminal data transmission. The transmission distance, transmission rate and bit error rate were tested with satisfactory results. The experimental re- sults are summarized, the increase of transmission distance, were reviewed and ideas to increase transmission range needs to expand its wireless network through a wireless communication base station, in the coverage of wireless communication base station, any wireless data transmission terminal can be effectively complete the data transmission between the host computer, and data exchange.

Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments.

Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

Design of Low Power Data Radio Transceiver Based on A7102C

Low power data radio transceiver was designed based on ATMEGA88PA microcontroller and A7102C RF chip. The design principle was described. The hardware circuit diagram and the software flow chart were given. Experimental results showed that in the 433MHz band the standby current was less than 2uA, the transmitting power was 14.9dbm, the receiving sensitivity was-110dbm and the communication distance was 1.2KM in open space.

RF calibration of on-chip DfT chain by DC stimuli and statistical multivariate regression technique

The problem of parameter variability in RF and analog circuits is escalating with CMOS scaling. Consequently every RF chip produced in nano-meter CMOS technologies needs to be tested. On-chip Design for Testability (DfT) features, which are meant to reduce test time and cost also suffer from parameter variability. Therefore, RF calibration of all on-chip test structures is mandatory. In this paper, Artificial Neural Networks (ANN) are employed as a multivariate regression technique to architect a RF calibration scheme for DfT chain using DC- instead of RF (GHz) stimuli. The use of DC stimuli relaxes the package design and on-chip routing that results in test cost reduction. A DfT circuit (RF detector, Test-ADC, Test-DAC and multiplexers) designed in 65nm CMOS is used to demonstrate the proposed calibration scheme. The simulation results show that the cumulative variation in a DfT circuit due to process and mismatch can be estimated and successfully calibrated, i.e. 25% error due to process variation in DfT circuit can be reduced to 2.5% provided the input test stimuli is large in magnitude. This reduction in error makes parametric tests feasible to classify the bad and good dies especially before expensive RF packaging.

The Research on Magnetic Target Detection Technology Based on Wireless Sensor Network

In the conditions of magnetic dipole model, this paper proposed forward a centroid localization algorithm on magnetic anomaly target based on wireless sensor network node which distribution are random and the improved the weighted centroid localization algorithm based on magnetic induction intensity. According to the fluctuation of magnetic field intensity which detected by magnetic sensors, that can detect the existence of magnetic anomaly target and its location. Established an experimental system of the wireless sensor network for magnetic anomaly detection whose core designs including the HMC1043 three-axis magnetic resistance sensor and the CC2530 Zigbee RF chip. The experimental results show that the algorithm can accurately positioning the magnetic anomaly target within the network.

RFID가 내장된 스마트 옷걸이를 이용한 의류 관리 시스템

In this paper, we proposed the clothing management system using the smart hanger. Proposed system consists of smart hanger, base module, and server, and the smart hanger consists of MCU, LED, RFID reader, RF chip, ring sensor, and battery. The smart hanger reads the RFID tag attached to the clothes and wirelessly transmitted to the server. The server associated base module communicates with the smart hanger and transmits information to the server. The server manages clothing through the DB, and can display various information through the web page and the smart phone. In order to verify the usefulness of the proposed system, we did experiment with the management system for clothing store and laundry where using a lot of hangers. Performance tests of the smart hanger are applied to check the current consumption and can be predicted the battery life with the proposed low power algorithm. The clothing store management system can be increased sales and convenience of the consumer. The laundry management system can be increased the efficiency of laundry category and convenience of the consumer.