Radio Frequency Receiver Research Articles

Single-Equipment with Multiple-Application for an Automated Robot-Car Control System.

The integration of greater functionalities into vehicles increases the complexity of car-controlling. Many research efforts are dedicated to designing car-controlling systems that allow users to instruct the car just to show it what it should do; however, for non-expert users, controlling the car with a remote or a switch is complicated. So, keeping this in mind, this paper presents an Arduino based car-controlling system that no longer requires manual control of the cars. Two main contributions are presented in this work. Firstly, we show that the car can be controlled with hand-gestures, according to the movement and position of the hand. The hand-gesture system works with an Arduino Nano, accelerometer, and radio-frequency (RF) transmitter. The accelerometer (attached with the hand-glove) senses the acceleration forces that are produced by the hand movement, and it will transfer the data to the Arduino Nano that is placed on hand glove. After receiving the data, Arduino Nano will convert it into different angle values in ranges of 0–450° and send the data to the RF receiver of the Arduino Uno, which is placed on the car through the RF transmitter. Secondly, the proposed car system is to be controlled by an android based mobile-application with different modes (e.g., touch buttons mode, voice recognition mode). The mobile-application system is the extension of the hand-gesture system with the addition of Bluetooth module. In this case, whenever the user presses any of the touch buttons in the application, and/or gives voice commands, the corresponding signal is sent to the Arduino Uno. After receiving the signal, Arduino will check this against its predefined instructions for moving forward, backward, left, right, and brake; then it will send the command to the motor module to move the car in the corresponding direction. In addition, an automatic obstacle detection system is introduced to improve the safety measurements to avoid any hazards with the help of sensors placed at the front of the car. The proposed systems are designed as a lab-scale prototype to experimentally validate the efficiency, accuracy, and affordability of the systems. The experimental results prove that the proposed work has all in one capability (hand-gesture, touch buttons and voice-recognition with mobile-application, obstacle detection), is very easy to use, and can be easily assembled in a simple hardware circuit. We remark that the proposed systems can be implemented under real conditions at large-scale in the future, which will be useful in automobiles and robotics applications.

Automatic Corporation Water Supply Control Using Arduino

The main aim of our project is to control the corporation water supplying for several areas from one control board. Here we have used Arduino board for controlling the System. For the communication purpose Radio Frequency (RF) transmitter and receivers are used. This will made the system more efficient for signal and information passing. Our project proposes an economic, efficient, eco-friendly system for controlling the corporation water supply. The advantages by our project are time management, proper drinking water supply with defined time, can reduce wastage of water.

Optical Comb Assisted OFDM RF Receiver

Orthogonal frequency-division multiplexing (OFDM) is a widely used signaling format in wireless communication and ultrawide band radio-frequency (RF) applications. An OFDM transceiver relies on a discrete Fourier transform (DFT) processor that matches both the resolution and the bandwidth of wireless link. A conventional wideband OFDM receiver necessarily relies on high-speed analog-to-digital converters (ADC) followed by a Fourier processing core. Both fundamental and practical ADC considerations that include bandwidth-resolution tradeoff impose strict limits on high precision digitization of the wideband OFDM signal. In addition to the quantization barrier, computational complexity of the high-speed DFT processor leads to high dissipation levels in conventional receivers. This report demonstrates an alternative OFDM receiver architecture that eliminates the need for high-speed ADC and digital DFT processor. The new design is based on hybrid, optoelectronic DFT processor, capable of generating DFT coefficients of wideband RF signal in real time. We demonstrate demodulation of a 4-quadratic amplitude modulation OFDM signal with 60 subcarriers positioned within 4–15.8 GHz band and separated by 200 MHz. The error vector magnitude is measured for all channels to characterize the performance of the comb-assisted OFDM RF receiver.

Water-Tunable Highly Sub-Wavelength Spiral Resonator for Magnetic Field Enhancement of MRI Coils at 1.5 T

In magnetic resonance imaging (MRI), several studies have demonstrated that the metamaterial-based structures can effectively improve the sensitivity, and thus the signal-to-noise ratio (SNR), of receiving radio-frequency (RF) coils. However, the use of metamaterials for this type of the MRI application is often limited due to the bulkiness of the metamaterial structure at RF wavelengths and a lack of frequency tunability of the final design. In this work, we propose a planar compact sub-wavelength (<; λ/50) spiral resonator to increase the sensitivity of a receive coil with frequency tunability for the 1.5 T MRI. Its double-layered spiral design with a cavity embedded in the substrate between the two spirals allows water deposition for frequency tuning. At the resonance frequency of 64 MHz, the spiral resonator shows a 24% improvement in terms of the B 1 - field at the depth of 30mm into a load experimentally. Even at a penetration depth as much as 60 mm (deep brain in the case of head imaging), an enhancement of 9% was observed. Moreover, the magnetic field enhancement comes with a decrease (10%) in specific absorption rate (SAR). In terms of tuning, by controlling the water level in the cavity, the proposed spiral resonator shows a wide tuning range of 35MHz, centered around 64 MHz, with high tunability sensitivity (2.4-0.75 MHz/ml or 15-4.8 MHz/mm), which is due to the fact that the tuning cavity is located between the two spirals, where the fields are highly confined.

Construction of a Wireless Smart Home System based on Voice Recognition

In this paper a design and construction of a wireless smart home system on voice recognition has been presented. The proposed system consists of a voice recognition module, Arduino Uno microcontroller, relay circuit and radio frequency transmitter and receiver. The voice recognition module needs to be trained first before it can be used to recognize commands. Upon successful recognition of voice command, the Arduino drives the corresponding load with the help of the relay circuit. Keyword : Wireless, smart home system, voice recognition DOI : 10.7176/ISDE/10-1-01

The Transimpedance Amplifier [A Circuit for All Seasons

Many of today's communication systems incorporate a transimpedance amplifier (TIA). Although the TIA concept is as old as feedback amplifiers [1], it was in the late 1960s and early 1970s that TIAs found widespread usage in optical coupling and optical communication receivers. In a patent filed in 1967, Miller proposes the circuit shown in Figure 1 [2], which consists of two TIAs for converting a photodiode's current to a differential output voltage. Additionally, these amplifiers have become popular in radio-frequency (RF) receivers in the past 10 years [3]. This article deals with TIA design for optical and RF applications.

The input protective circuit of receiver radio frequency path with fixed restriction level

Представлены результаты разработки входной защитной цепи, предназначенной для ограничения сигналов большой мощности, которые могут наводиться в антенне и поступать в радиочастотный тракт коротковолнового приемника. Входная защитная цепь интегрируется в радиочастотный тракт и предохраняет чувствительные узлы приемника от перегрузки и выхода из строя. Проведены успешные практические испытания опытных образцов входной защитной цепи, установленной на входе серийно выпускаемого коротковолнового приемника. Обоснован экономический эффект от внедрения разработки. Посный О. А., Долгушев С. В., Посная Е. А. Входная защитная цепь радиочастотного тракта приемника с заданным уровнем ограничения. Ural Radio Engineering Journal . 2019;3(3):243–250. DOI: 10.15826/ urej.2019.3.3.002

Design and Measurement of 3D Flexible Antenna Diversity for Ambient RF Energy Scavenging in Indoor Scenarios

Ambient radiofrequency (RF) energy scavenging has been recently addressed with a wide range of studies to provide alternative powering for low-power applications. However, due to the low power level of the ambient electromagnetic field, the efficiency of the latter systems is still below expectations. Multipath in the environment may be considered and antenna diversity is then a solution for quasi-omnidirectional RF reception to reach a higher probability of receiving energy in a realistic situation. A 3D flexible antenna diversity, which can be integrated into the rectangular packaging, is proposed in order to take advantage of system packaging form. The angle and polarization diversity antenna was designed on flexible substrate in order to achieve the flexibility and low-cost. This design overcomes the low performance of the substrate while maintaining a compact, high isolation, and good radiation efficiency of the antenna. An indoor experimental setup was carried out to compare different rectenna configurations. The measurement results validate the principle and demonstrate the performance of the 3D flexible diversity system. The probability measurements were carried out under precise conditions in indoor scenarios and the results in comparison with statistic models confirmed the performance of the system in such low power conditions.

A Generic Receiver Architecture for MIMO Wireless Power Transfer With Nonlinear Energy Harvesting

This letter investigates a multiple-input multiple-output (MIMO) wireless power transfer (WPT) system under practical non-liner energy harvesting (EH) models. We propose a new generic energy receiver (ER) architecture consisting of $N$ receive antennas and $L$ rectifiers, for which one power splitter is inserted after each antenna to adaptively split the received radio frequency (RF) signals among the $L$ rectifiers for efficient non-linear RF-to-direct current (DC) conversion. With the proposed architecture, we maximize the total harvested DC power at the ER, by jointly optimizing the transmit energy beamforming at the energy transmitter (ET) and the power splitting ratios at the ER. Numerical results show that our proposed design by exploiting the nonlinearity of EH significantly improves the harvested DC power at the ER, as compared to two conventional designs.

Design and Fabrication of an Electrostatic AlN RF MEMS Switch for Near-Zero Power RF Wake-Up Receivers

We describe an aluminum nitride (AlN)-based resonant switch for use in a near zero power radio frequency (RF) wake-up receiver. A folded beam structure with a slot compensates for the curvature caused by the stress gradient in the sputtered AlN film and ensures that the released contact gap is approximately equal to the designed contact gap. A 80 kHz resoswitch with a Q of 8600 and an actuation gap of approximately 600 nm turns on when a −4 dBm, 800 MHz signal, square wave modulated at 80 kHz, is applied to the actuator. This AlN electrostatic resonant switch is designed to enable integration with a high gain AlN RF piezoelectric transformer to form a complete ultra-low power RF receiver.

Design and Optimization of a Direct-Conversion Double-Balanced Mixer for RF Receiver Front-End

Differential implementation is becoming highly favoured in RFIC (radio frequency integrated circuit) design, notably its high immunity to common-mode noises, acceptable rejection of parasitic coupling, and increased dynamic range. One specific RF front-end building block that is usually designed as a differential circuit is the mixer. This technical paper presents a study of a differential mixer, notably the double-balanced mixer implemented on a direct-conversion architecture in a standard 90nm CMOS (complementary metal-oxide semiconductor) process. Operating frequency is set at 5GHz, which is a typical frequency for RF (radio frequency) receiver. Impedance matching was essential to fully optimize the mixer design. The direct-conversion double-balance mixer design eventually achieved conversion gain of 11.463dB and noise figure of 16.529dB, comparable to mixer designs from past research and studies.

Analysis of time-switching and power-splitting protocols in wireless-powered cooperative communication system

SWIPT techniques combined with wireless cooperative communication provides a sustainable solution to extend the lifetime of the communication networks. It prolongs the battery life of wireless low-powered devices and enables additional efficiency in terms of power in wireless communications. This paper explores performance difference of two simultaneous wireless information and power transfer (SWIPT) protocols named Time-Switching (TS) and Power-Splitting (PS). Two identical decode-and-forward relaying communication networks with multiple relays are considered, where energy constrained relay nodes harvest energy from the received Radio Frequency (RF) and use harvested energy to assist information transmission between the source and the destination. All relay nodes in one network use TS protocol while the relay nodes in the other network use PS protocol. In particular, we evaluate throughput and outage probability of maximal ratio combiner (MRC) output at the destination node of both systems. In order to evaluate throughput, outage probability is derived for delay-limited transmission mode. The numerical results provide practical insight into the performance difference in various system parameters for both TS and PS protocols. Simulation results obtained depict that the TS protocol is superior to PS protocol in performance parameters, BER, Outage probability and throughput in low transmission rate. However, in higher transmission rates PS becomes superior to TS protocol, though overall performance reduce compare to lower transmission rate.

A Digital Multibeam Array With Wide Scanning Angle and Enhanced Beam Gain for Millimeter-Wave Massive MIMO Applications

A novel full-digital multibeam array with wide scanning angle and enhanced beam gain is proposed for millimeter-wave massive multiple-input multiple-output applications. The array consists of 16 dual exponentially tapered slot antenna (DETSA) elements. Each element is integrated with a radio frequency receiver, an intermediate frequency chain, and an analog-to-digital converter (ADC). The H-plane radiation pattern of the proposed DETSA is very wide to enable the beam scanning in the azimuth plane. The beam gain is further enhanced by employing a 1-D multilayered planar lens that transforms the spherical wave into a plane wave in the E-plane for increasing the beam gain and keeping the phase compensation unaltered in the H-plane. Meanwhile, the planar lens is optimized to guarantee the wide scanning angle. In addition, all the signals received by the 16 independent channels are converted to a digital signal via ADC simultaneously and then used for synthesizing the multibeam patterns in the digital domain. Furthermore, the calibration and the verification of the synthesizing weights are discussed in detail. The measured results show that a scanning coverage of ±40° in the H-plane (or in horizontal plane) and an estimated maximum gain of 24.8 dBi with a gain tolerance of 3 dB can be achieved by the proposed 16-element array with a 1-D lens.

Design of Low Noise Amplifier for 1.5 GHz

Low Noise Amplifier (LNA) is a front-end device of a radio frequency (RF) receiver used to increase the amplitude of an RF signal without much additional noise, thereby increasing the noise figure of the system. This paper presents design, simulation, and prototype of an LNA operating at 1.5 GHz for the bandwidth of 100 MHz. The circuit was simulated using Advanced Design System (ADS). The components used are Surface Mount Devices (SMDs); with transistor "Infineon BFP420" as a major component. Other components are resistors, capacitors, and inductors; inductors being superseded by microstrip lines. The circuit was fabricated on FR4 board. The measurements of several parameters of LNA were made using Vector Network Analyzer (VNA), Noise Figure Meter; and Spectrum Analyzer. The LNA has minimum gain of 15.4 dB and maximum noise figure of 1.33 dB. It is unconditionally stable from 50 MHz to 10 GHz. DC supply is 5V and the current consumption is 10 mA. This LNA offers Output-Third­Order-Intercept-Point (OJP3) of about 1 4 dBm.

Broadband lower-IF RF receiver based on microwave photonic mixer and Kramers-Kronig detection.

A broadband lower- intermediate-frequency (IF) radio frequency (RF) receiver with low cost and complexity based on a microwave photonic mixer and Kramers-Kronig (KK) detection is proposed and experimentally demonstrated. The feasibility of the proposed RF receiver is verified by comparing the error vector magnitude (EVM) performance of a down-converted IF signal with and without KK detection. EVM is measured as a function of IF carrier frequency, input local oscillator (LO) power, input RF power, and the coupling ratio between RF and LO paths. With KK detection, EVM can be improved by more than 9.5% when the IF carrier frequency is close to half of the signal bandwidth. This implies that a lower IF frequency can be down-converted with good EVM and that a low-speed photodetector and a low sampling rate analog to digital converter can be used for wideband RF signal reception.

A Decomposition Method for MIMO OTA Performance Evaluation

Diagnosis and troubleshooting are critical to efficiently detecting the imperfections and improving the radio frequency designs for wireless systems in the research and development stage. For achieving these, this paper proposes a decomposition method for the measurement of multi-input multi-output (MIMO) devices’ over-the-air (OTA) performance. By using the proposed method, the antenna active envelope correlation coefficient, the radiated sensitivity of each receiver, the total isotropic sensitivity, the self-interference, and the desensitization can all be achieved separately, and in the OTA working mode. In consideration of the MIMO system's complex array antennas and radio frequency receivers, the parameters obtained by this decomposition method are significant for discovering the imperfections, for debugging, and for improving the design of the devices. It is a valuable tool to raise the debugging efficiency of MIMO systems.

Development of an Automatic Mini-Conveyor System for Product Monitoring

This thesis presents the development of an automatic mini-conveyor system for product monitoring. It is aimed at solving relative industrial and manufacturing problems such as product pilferage, inefficient supervision, monitoring and workmanship. It is also to improve production management system, using ICT based platform to enhance monitoring control and data acquisition (MCDA) system in manufacturing process. ASSEMBLY programming language was used on a programmable logic controller (Atmel 89C52) microcontroller for control and monitoring protocol. The method includes; simulation, hardware development; to include; sensing, counting and signalling wireless system containing sensors and a wireless radio frequency transmitter and receiver. Design calculation analysis, fabrication and operational tests were carried out on the developed mini-conveyor. The operational and test result shows that, the time the product travels along the conveyor through a distance of 0.8m between entrance and exit point sensors was between 15.7sec to 16.3sec. At a distance of 0.096metres between sensors, the response to display time on LCD is approximately 1.0 second. The developed mini-conveyor system is able to remotely monitor a product on a communication distance of 22 metres in which the required information is displayed on computer screen on a telnet hyper-terminal platform, through a baud rate of 1200. Therefore, the developed machine has open opportunities for product monitoring control and data acquisition in material handling systems in the industries for more accountability.

A 1-GS/s 11-Bit SAR-Assisted Pipeline ADC With 59-dB SNDR in 65-nm CMOS

We present an 11-bit 1-GS/s time-interleaved ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 2$ </tex-math></inline-formula> ) successive approximation register (SAR)-assisted pipeline analog-to-digital converter (ADC) for wideband direct sampling radio-frequency receivers. The proposed ADC architecture combines the speed advantage of the pipeline algorithm and the structural simplicity of the SAR structure. Consequently, both the structure and the operation of the pipeline stages are simplified, thereby enhancing the conversion rate and accuracy. In particular, the proposed ADC eliminates the multiplying digital-to-analog converter in the conventional pipeline ADC, hence compatible with process portability. The prototype ADC fabricated in 65-nm CMOS process achieves SNDR ≥ 56-dB across 500-MHz Nyquist bandwidth at 1GS/s conversion rate with 230-mW power dissipation. When benchmarked against state-of-the-art pipeline ADCs, it features a competitive figure-of-merit, i.e., 449.2 fJ/conv.-step.

Antarctic surface reflectivity calculations and measurements from the ANITA-4 and HiCal-2 experiments

The balloon-borne HiCal radio-frequency (RF) transmitter, in concert with the ANITA radio-frequency receiver array, is designed to measure the Antarctic surface reflectivity in the RF wavelength regime. The amplitude of surface-reflected transmissions from HiCal, registered as triggered events by ANITA, can be compared with the direct transmissions preceding them by O(10) microseconds, to infer the surface power reflection coefficient $\cal{R}$. The first HiCal mission (HiCal-1, Jan. 2015) yielded a sample of 100 such pairs, resulting in estimates of $\cal{R}$ at highly-glancing angles (i.e., zenith angles approaching $90^\circ$), with measured reflectivity for those events which exceeded extant calculations. The HiCal-2 experiment, flying from Dec., 2016-Jan., 2017, provided an improvement by nearly two orders of magnitude in our event statistics, allowing a considerably more precise mapping of the reflectivity over a wider range of incidence angles. We find general agreement between the HiCal-2 reflectivity results and those obtained with the earlier HiCal-1 mission, as well as estimates from Solar reflections in the radio-frequency regime. In parallel, our calculations of expected reflectivity have matured; herein, we use a plane-wave expansion to estimate the reflectivity R from both a flat, smooth surface (and, in so doing, recover the Fresnel reflectivity equations) and also a curved surface. Multiplying our flat-smooth reflectivity by improved Earth curvature and surface roughness corrections now provides significantly better agreement between theory and the HiCal 2a/2b measurements.

Real-Time Magnetic Resonance Imaging of Bubble Behavior and Particle Velocity in Fluidized Beds

Snapshots of particle concentration and velocity fields in bubbling gas–solid fluidized beds were acquired using magnetic resonance imaging. Using a recently developed multichannel radiofrequency receiver coil in combination with fast readout techniques, adapted from medical MRI protocols, the temporal resolution was 7 and 18 ms for two-dimensional images of particle concentration and velocity fields, respectively. A cylindrical bed with 190 mm diameter and 300 mm height was filled to heights of 100, 150, and 200 mm with spherical 1 and 3 mm diameter particles and fluidized at ratios of superficial gas velocity to minimum fluidization velocity (U/Umf) of 1.2, 1.5, 2.0, 3.0, and 4.0. The effects of these varying parameters on the number of bubbles, bubble diameter, bed height, and particle speed are investigated. It is hoped that these data sets will become important benchmarks against which computational, analytical, and empirical models can be validated.