RF Receiver Research Articles

Balanced to Unbalanced: An Overview of Multifunctional Wideband Balanced-to-Unbalanced Four- and Five-Port Filtering Power Dividers

Fifth-generation (5G) communication techniques are growing in popularity, and 5G will become the commercial operation standard for mainland China in 2020 [1]. As the next-generation mobile communication network, 5G will not only greatly improve communication efficiency; it will also change the way people live and work. The 5G communication system contains the millimeter-wave and sub-6-GHz bands. For the sub-6-GHz band, circuits are becoming ever more compact and multifunction; thus, electromagnetic interference and multicoupling problems will greatly affect the entire system's performance [2]-[4]. In response, balanced circuits with higher immunity to environmental noises [5]-[8], lower electromagnetic interference [9]-[11], and better dynamic range [12]-[15] have attracted increasing attention in the past few years, and a large number of balanced circuits are being conceived [16], [17]. Currently, all feature differential-mode input and output terminals, so they cannot be connected directly to single-ended circuits. Balanced filters, antennas, and power dividers that can be cointegrated with balanced active circuits are required for the development of fully balanced transmitter and receiver RF chains, such as the balanced power dividers that can be connected to a Doherty power amplifier in a balanced system. In this case, balancing is only necessary at the input and output stages. It is expected that the transistor stage is still a single-ended structure, where only two amplifier devices are needed [18].

Flexible reconfigurable GNSS RF receiver for portable application of Internet of Things

A fully integrated single input, dual-channel, single-band reconfigurable GNSS radio frequency receiver supporting GPS, BD2 and Galileo systems is designed and implemented in a 0.18 ​μm CMOS process for portable Internet of Things applications. The receiver incorporates a single RF front-end, low-power fractional-N synthesizer, and reconfigurable complex band-pass filter, which can be flexibly configured to receive GPS L1/BD2 B1 or GPS L1/Galileo E1, and any of these signals separately, and can also effectively simplify the design complexity of the receiver and reduce power consumption. Moreover, a flexible frequency plan is employed to meet the different frequency requirements of the receiver. While drawing 16 ​mA current from a 1.8 ​V supply, this RF receiver achieves a total noise figure of 1.79 ​dB, a maximum voltage gain of 108 ​dB, a gain dynamic range of 56 ​dB and the input third-order intercept point of -18.09 dBm and -23.66 dBm at 1575 ​MHz and 1561 ​MHz, respectively, with an active die area of 1.86 ​mm2.

Steel health monitoring device based on Hall sensors

A new, portable device is presented, which can be used to monitor changes in the magnetic properties of a ferromagnetic material, such as steel, due to stresses or other effects, through measurements of magnetic flux density. The device consists of a yoke, formed of a permanent magnet, which provides a constant flux density, and two high permeability soft ferromagnetic poles. The yoke is placed above the material under test, forming a magnetic circuit. Two Hall sensors placed at the ends of the yoke’s poles measure the magnetic flux density. Through this arrangement, the ambient magnetic field is cancelled and the changes in the magnetic flux density values depend only on the changes in the magnetic properties of the sample’s material participating in the magnetic circuit. The optimal parameters of the device, such as the lift-off distance between the yoke and the sample, were selected based on simulation results. The device includes the above-mentioned sensing element, a microcontroller, a temperature sensor, an Analog-to-Digital converter, an RF transmitter, a Bluetooth module and a battery. The collected data are wirelessly transmitted to a receiving device, consisting of a microcontroller, an RF receiver, an LCD and a battery. The output information can be viewed either on the dedicated device or on any other Bluetooth-compatible device (e.g. smartphone, tablet, laptop etc).

Single-Event Transients in an IEEE 802.15.4 RF Receiver for Wireless Sensor Networks.

This paper presents a procedure to analyse the effects of radiation in an IEEE 802.15.4 RF receiver for wireless sensor networks (WSNs). Specifically, single-event transients (SETs) represent one of the greatest threats to the adequate performance of electronic communication devices in high-radiation environments. The proposed procedure consists in injecting current pulses in sensitive nodes of the receiver and analysing how they propagate through the different circuits that form the receiver. In order to perform this analysis, a Complementary Metal Oxide Semiconductor (CMOS) low-IF receiver has been designed using a 0.18 μm technology from the foundry UMC. In order to analyse the effect of single-event transients in this receiver, it has been studied how current pulses generated in the low-noise amplifier propagate down the receiver chain. The effect of the different circuits that form the receiver on this kind of pulse has been studied prior to the analysis of the complete receiver. First, the effect of SETs in low-noise amplifiers was analysed. Then, the propagation of pulses through mixers was studied. The effect of filters in the analysed current pulses has also been studied. Regarding the analysis of the designed RF receiver, an amplitude and phase shift was observed under the presence of SETs.

Wireless Gesture Control Wheelchair

Wheelchairs have been used by patients who suffer from various physical disabilities to help them with locomotion and cater their day to day needs with ease. But there are some cases where the movement of a wheelchair is dependent on another individual as is the case with patients who lack the required arm strength and movement to properly push the wheels forward such as quadriplegics, paraplegics, stroke patients, elders etc. Joystick oriented wheelchairs, thought to be a solution to those kinds of patients, can pose different problems as it requires basic shoulder movement. It is not always possible for the aforementioned types of patients. In addition, our solution doesn’t have the positional constraints that a joystick wheelchair might have as it is wireless and can be worn on either hand which allows the patient to sit in their preferred position for minimum discomfort. This project is an attempt to help the disabled move around independently. Thus, in this research work, we present a prototype of a wireless gesture-based wheelchair which can be controlled via hand gestures. The framework consists of a transmitter and a receiver that communicate with each other wirelessly. For wireless transmission, 433Mhz RF Transmitter and Receiver Unit has been used as it transmits data through an antenna at the speed of 1Kbps – 10Kbps and the range can be adjusted as required. The transmitter unit consists of an Arduino LilyPad microcontroller and an accelerometer that has been attached to a hand glove. The accelerometer sensor has been used to register the position of the hand while creating a gesture. This glove is supposed to be worn by the patient allowing them to move their hand conveniently, sending signals to the receiver unit connected to the wheelchair leading to the movement of the wheels in the desired direction. The receiver unit consist of motor drivers that convert the voltage as needed by the wheels. This paper presents an alternative to the commercial wheelchairs as it is cost effective, easy to control and efficient. The working and assembly of the system has been explained in the paper.

Adaptive low-power CMOS LNA in internet of things based wireless sensor networks

With the increasing need for the Internet of things (IoT), wireless communication has become a popular technology for the network. This explosion of IoT wireless applications makes the power consumption a key metric in the design of wireless sensor nodes. The major constraint of the wireless sensors nodes is battery energy, which is the mainly challenging problem in designing IoT network. these constraints have imposed new yet stringent specs to the design of RF front-ends. The design of adaptive radio-frequency circuits, in order to reduce power consumption, is of interest. In a RF receiver chain, the Low Noise Amplifier (LNA) stand as critical elements on the power consumption.To address this purpose, this paper proposes a design strategy for an adaptive Low Noise Amplifier as the first element of the receiver chain. Hence the proposed LNA achieves the correct QoS for various scenario of communications. Using the proposed LNA, a significant trade-off between a conversion gain, noise figure and energy consumption is presented.

IOT based Monitoring and Detection of Electromagnetic (EM) Radiation Levels

EM radiations are considered as one of the major reasons for effecting and heating up the body tissues that could even burn when exposed at certain frequencies. At lower frequencies, external electric and magnetic fields induce circulating currents inside the body and radiations from EM devices are very harmful for human health. One such example is mobile phones which we always carry and utilize in our daily routines. Radiations emitted from mobile phones are harmful to human health. Hence, it is of paramount importance to detect and monitor EM radiation levels so that preventive measures could be taken to minimize or to completely avoid such radiations at prohibited areas such as Hospitals. The main aim of the proposed work is real time monitoring of the EM radiations emitted from mobile phones and comparing with FCC and ICNIRP levels that is allowed for general public. The system is mainly composed of arduino uno, RF detector and receiver, 16*2 LCD display, ESP 8266. Arduino Uno acts as a controller and responsible for converting voltage level to electric field value. RF receiver with RF detection circuit detects the radiations from the surrounding. 16*2 LCD will display electric field value. If the electric-filed value is greater than the allowed range, the piezo electric buzzer will turn on. The ESP8266 Wi-Fi module will upload the electric-field value data on the Think Speak cloud so that the radiations level can be monitored remotely. Simulation is done using proteus ISIS and finally the hardware is implemented to showcase the results.

Gesture recognition vehicle using PIC microcontroller

<p>In this paper we introduce a hand controlled robotic vehicle. Hand control robotic vehicle consists of a transmitter module and a receiver module. The transmitter will be placed on a hand glove and the receiver will be placed on the motor drive along with PIC microcontroller and motor driver IC. The RF transmitter sends commands to the IC which then forwards the commands to RF receiver. The RF receiver then sends the commands to PIC microcontroller on the vehicle which processes the commands so that the vehicle moves in the specified direction. It is having proposed utility in field ofconstruction, hazardous waste disposal and field survey near borders etc. This project is developed as a travel buddy and industrial uses. Having future scope of advanced robotics that are designed and can be easily controlled using hand gesture only.</p>

The design of large image rejection and wideband CMOS active polyphase filter for BeiDou RF receiver

The design of large image rejection and wideband CMOS active polyphase filter for BeiDou RF receiver

I/Q Balance-Enhanced Wideband Receiver Front-End for 2G/3G/4G/5G NR Cellular Applications

In this paper, an in-phase (I) and quadrature-phase (Q) balance-enhanced wideband receiver RF front-end is proposed using a quadrature sampling passive mixer configuration, which can be applicable to 2G/3G/4G/5G new radio (NR) applications. Compensating mixer switches are additionally utilized in parallel with main mixer switches in a quadrature mixer for quadrature downconversion. As a consequence, gain and phase errors from the mixer can be mutually compensated at the mixer output, and I/Q imbalance characteristics are significantly improved without an extra calibration process. For the verification of I/Q balancing improvement, the receiver front-end is implemented, which consists of a wideband low noise transconductance amplifier, a double-balanced quadrature sampling passive mixer, transimpedance amplifiers, and quadrature local oscillator signal circuitry. The demonstrated design is fabricated in a 65-nm CMOS process and mainly characterized in long-term evolution (LTE) frequency bands. The implemented design achieves an error-vector magnitude of less than 2% with conversion gains and noise figures of more than 41 dB and less than 4.7 dB for all frequency bands, respectively. Moreover, the design attains in-band and out-of-band IIP3s of higher than −12 dBm and −2.7 dBm for LTE frequency division duplexing test conditions, respectively. The active die area of the implemented receiver front-end is 0.72 mm2. It draws a bias current of 18.2 mA from a nominal supply voltage of 1.2 V.

Hand Gesture Controlled Robot using Arduino and MPU6050

As the use of robots in different fields has been increasing day by day in doing different types works. To make some complicated works easy in industrial areas, military purpose and in any places where human can’t go, the gesture controlled robot are used in which the motion of robot is dependent on the human hand. We are using the MPU6050 sensor which has 6-axis of motion tracking device in which accelerometer has 3-axis, gyroscope has the other 3-axis and it also has an additional feature like temperature sensor. Where the acceleration is a keyword of an Inertial Measurement Unit. Accelerometer meter is a device used to sense acceleration off gravity of directions like forward, backward, left and right. The movement of the robot has been controlled by the accelerometer. By which the information from RF Transmitter to the RF Receiver has been pass through wireless communication system. The other parts are control Arduino in which the code is dumped.

Tradeoffs Between RF Performance and SET Robustness in Low-Noise Amplifiers in a Complementary SiGe BiCMOS Platform

Low-noise amplifiers (LNAs) are necessary components for any communications system. Single-event transients (SETs) induced by energetic particles in space can corrupt the data in an RF receiver. Using p-n-p silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs), instead of their more common n-p-n counterparts, has been shown to be an effective mitigation technique in digital, analog, and RF circuits. Since p-n-p SiGe HBTs tend to have lower performance than n-p-n SiGe HBTs, in this article, the tradeoffs between performance and SET robustness have been evaluated through the use of simulations. Two LNAs were designed using an algorithmic design technique: one using only n-p-n SiGe HBTs, and the other using only p-n-p devices. The n-p-n LNA had higher peak gain and lower noise figure at the center frequency of 5 GHz when compared to the p-n-p LNA, by 3.2 and 0.4 dB, respectively. However, the n-p-n LNA also produced transients with amplitudes larger than the p-n-p LNA across all simulated linear energy transfers. Although the p-n-p LNA has lower overall performance, it is also more robust to SETs. Thus, the choice between using n-p-n and p-n-p SiGe HBTs for an RF design will depend on application requirements.

Experimental Implementation of a Low-Cost, Fully-Analog Self-Jamming Canceller for UHF RFID Devices

It is quite common for transceivers to operate with the RF receiver and transmitter working on different time slots. Typical applications are radars and transceivers in the field of communications. Generally, the receiver is turned off when the transmitter broadcasts and vice versa. This is done in order to prevent the transmitter from blinding the receiver or causing the RF low noise amplification (LNA) stage to saturate. When keeping a receiver active, some leakage of RF energy is inevitable, and therefore shielding is applied to mitigate spurious signals. However, there are many applications wherein the receiver cannot be turned off. To address these applications, we investigate the design and performance of a fully-analog self-jamming canceller able to operate in UHF (Ultra High Frequency) RFID devices. While the traditional cost to design and build this type of topology can be quite high, our proposal is based on a low-cost physical approach. In addition to using common SMT (Surface Mount Technology) devices, we leveraged a new piece of modular technology offered by X-Microwave which allows designers to easily produce RF solutions with a broad portfolio of modular system drop-in blocks. A prototype was realized and the measured results are in close agreement with theoretical simulations. Significant damping of the leaked signal in the receiving channel was realized.

Cloud based RC Book Verification

In the field of transportation , there are such a large amount of documents want to be maintained for every automobile.So, at the same time as driving on public roadways each car proprietor has to carry all of the updated documents of a automobile with them. But it is very hard for proprietor to preserve all of the car documents like RC e book, insurance details, and greater collectively with them always. The misplacement or damaging of files due to climatic situations or as time passes are the biggest issues. If the driving force forgot to carry every body of these documents, he want to present heavy fines.With this "Cloud Based RC book Verification using RF transmitter and Receiver", vehicle documents can be electronically verified which helps in time consumption. The receiver identifies each car with unique frequency emitted from character transmitter. The RF receiver is connected to a cloud, this cloud shops all of the documents related to automobile and fetches all the information associated with the automobile, the statistics's includes RC ebook, proprietor details, smoke check details, and more. This idea may also be helps to tune stolen with the assist of authorities.

Avoidance of Collision using Copy Cat Technology

The project aims to design an android interface Bluetooth controlled robotic car with master-slave configuration involved in it. Robotic car contains arduino microcontroller with basic mobility features. Arduino programs contain instructions mediating between Android controller and Robotic car. An appropriate program in the arduino microprocessor to interact with the android controller has been created. The program has been successfully complied through arduino IDE to the arduino microprocessor & loaded into it after proper checking of logic to decrease any loss/damage of hardware. An android application that would provide a user interface to interact with the arduino powered robotic car was created. This interface is easy to use and provide feedback from the arduino microprocessor through the Bluetooth after giving instruction to arduino for various actions via Bluetooth module. The android application is created with the help of android studio that provides more capability & stability. This project also describes the robots that are configured in master slave technology. In this case the user sends the data from the android device which is received and executed by the master robot and simultaneously the data is broadcasted to the slave robots through the RF transmitter. Slave robots receive the data from the RF receiver, decode it and send the command to Arduino and from then to the motors. Also, there is a provision that any of the robots shall be made the master of the remaining robots. Under any dangerous circumstances (Ex: when the driver is asleep while driving) slave robot uses the path which is followed by master as a navigation and moves in that particular direction. By this technology one shall reduce the number of accidents which leads to decrease of death rate.

Phantom Bat for Military Applications

The aim of this project is to minimize the cause of death of military man and innocent people by gathering their secret informations . The Phantom bat act as spy because it looks similar like a bat. It is fixed with ESP 32 WIFI camera to monitor the activities of the enemies. This bat design does not create any doubt to the enemies we are watching. It flies using a BLDC motor. The BLDC motor help the bat to lift from the ground and allow it to fly in the sky by creating 3 flaps per second to the wings which is fixed with the body of the bat. The two servo motors are used to control altitude and direction. All the electronics components present in flight board are controlled by the Arduino pro micro which is connected with RF receiver. RF transmitter will act as a remote controller and control the operation of bat. Here mobile phone will act as a display for the camera which we used. This bat will play a major role in military to save life. In future it will work on its own by implementing Artificial Intelligence and does not need manual control for this bat.

Through-the-wall radar detection using machine learning

This paper explores the through-the-wall inverse scattering problem via machine learning. The reconstruction method seeks to discover the shape, location, and type of hidden objects behind walls, as well as identifying certain material properties of the targets. We simulate RF sources and receivers placed outside the room to generate observation data with objects randomly placed inside the room. We experiment with two types of neural networks and use an 80-20 train-test split for reconstruction and classification.

A 2.4 GHz 2.9 mW Zigbee RF Receiver with Current-Reusing and Function-Reused Mixing Techniques

This study presents a low-power Zigbee receiver with a current-reusing structure and function-reused mixing techniques. To reduce the overall power consumption, a low noise amplifier (LNA) and a power amplifier (PA) share the biasing current with a voltage-controlled oscillator (VCO) in the receiving (RX) mode and transmitting (TX) mode, respectively. The function-reused mixer reuses the radio frequency trans-conductance (RF gm) stage to amplify the down-converted intermediate frequency (IF) signal, obtaining a free IF gain without extra power consumption. A peak detector circuit detects the receiving signal strength and auto-adjusts the biasing current to save power when a strong signal strength is detected. Meanwhile, the peak detector helps to provide a coarse gain control as part of the auto-gain-control function. As part of the IF gain range is shared by the multiple-feedback (MFB) low-pass filter, the number of programmable-gain IF amplifier stages can be reduced, which also means a decrease in power consumption. A prototype of this wireless sensor network (WSN) receiver was designed and fabricated using the TSMC 130 nm CMOS process under a supply voltage of 1 V. The entire receiver realizes a noise figure (NF) of 3.5 dB and a receiving sensitivity of −90 dBm for the 0.25 Mbps offset quadrature phase shift keying (O-QPSK) signal with a power consumption of 2.9 mW.

Surveillance and Security for Correctional Facilities

Prisoners are segregated in different wards. But it is the tendencies of a few bad elements to leave the barracks on the pretext of availing medical services, canteen services and telephone services etc., and going to some other barracks to receive or distribute prohibited articles. To overcome this situation, a system is proposed for the surveillance of the prisoners, using biometric sensors for monitoring purpose. This project overcomes the limitations of the existing systems of correctional facilities. In this proposed method the finger prints of the prisoners are taken as input and the other parameters that apply are the source and destination along with the time difference. Thus, the proposed system will make prisons more secure. This work provides more secure and efficient way to eliminate the wrong traversals and to inform the officials about it when this happens. The biometric sensor along with LED display, the alarm, RF receiver, RF transmitter is integrated with the PIC microcontroller. The fingerprint module takes the input and identifies the prisoner and then displays the details in the LED screen. Source controller RF and the destination RF interact, as soon as the prisoner checks in, the timer starts to function and counts until prisoner reaches. If the prisoner does not reach before the average time taken, then the alarm goes on and the official can know along with the prisoner ID on the screen. Thus the proposed system gives a better monitoring and control over the prisoners.

System to Control the RF Receiver Noise Parameters of the Radiolocation Pre-Search Station P18 Laura

The article presents a measuring system that allows the noise parameters of the receiver of a radiolocation station to be controlled. The existing solutions of the radiolocation pre-search station P18 Laura control unit have been adapted to the system.