Short-range Applications Research Articles

Design and analysis of an optical camera communication system for underwater applications

The growing interest in underwater explorations has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication (UWC) systems. The study presents the design and implementation techniques of a short-range unidirectional UWC system which uses optical camera communication (OCC) principles. OCC systems have light emitting diodes at the transmitter, with the receiver being a camera. Overall system design considerations, synchronisation and frame selection, and a novel spatial position-based image processing algorithm to decode data from frames are discussed. Also, the optimisation techniques used in the image processing algorithm are also elaborated. Importance of few of key features of an OCC system, namely camera quality, transmission distance and the threshold value used for image binarisation are demonstrated through numerical results using simulations via synthetically generated images. Further, the bit error rate (BER) performance of the system is evaluated using the experimental proof of concept setup in clear water, muddy water and under turbulence conditions. Overall BER performance in the order of 10 -3 within the communication distance of 1 m is observed, and it shows that the proposed system design and algorithms can be used to realise an UWC link for short-range applications successfully.

Millimeter Wave Propagation Measurements and Characteristics for 5G System

In future 5G systems, the millimeter wave (mmWave) band will be used to support a large capacity for current mobile broadband. Therefore, the radio access technology (RAT) should be made available for 5G devices to help in distinct situations, for example device-to-device communications (D2D) and multi-hops. This paper presents ultra-wideband channel measurements for millimeter wave bands at 19, 28, and 38 GHz. We used an ultra-wideband channel sounder (1 GHz bandwidth) in an indoor to outdoor (I2O) environment for non-line-of-sight (NLOS) scenarios. In an NLOS environment, there is no direct path (line of sight), and all of the contributed paths are received from different physical objects by refection propagation phenomena. Hence, in this work, a directional horn antenna (high gain) was used at the transmitter, while an omnidirectional antenna was used at the receiver to collect the radio signals from all directions. The path loss and temporal dispersion were examined based on the acquired measurement data—the 5G propagation characteristics. Two different path loss models were used, namely close-in (CI) free space reference distance and alpha-beta-gamma (ABG) models. The time dispersion parameters were provided based on a mean excess delay, a root mean square (RMS) delay spread, and a maximum excess delay. The path loss exponent for this NLOS specific environment was found to be low for all of the proposed frequencies, and the RMS delay spread values were less than 30 ns for all of the measured frequencies, and the average RMS delay spread values were 19.2, 19.3, and 20.3 ns for 19, 28, and 38 GHz frequencies, respectively. Moreover, the mean excess delay values were found also at 26.1, 25.8, and 27.3 ns for 19, 28, and 38 GHz frequencies, respectively. The propagation signal through the NLOS channel at 19, 28, and 38 GHz was strong with a low delay; it is concluded that these bands are reliable for 5G systems in short-range applications.

Development and Demonstration of MIMO-SAR mmWave Imaging Testbeds

Multiple-input multiple-output (MIMO) radars and synthetic aperture radar (SAR) techniques are well researched and have been effectively combined for many imaging applications ranging from remote sensing to security. Despite numerous studies that apply MIMO concepts to SAR imaging, the design process of a MIMO-SAR system is non-trivial, especially for millimeter-wave (mmWave) imaging systems. Many issues have to be carefully addressed. Besides, compared with conventional monostatic sampling schemes or MIMO-only solutions, efficient image reconstruction methods for MIMO-SAR topologies are more complicated in short-range applications. To address these issues, we present highly-integrated and reconfigurable MIMO-SAR testbeds, along with examples of three-dimensional (3-D) image reconstruction algorithms optimized for MIMO-SAR configurations. The presented testbeds utilize commercially available wideband mmWave sensors and motorized rail platforms. Several aspects of the MIMO-SAR testbed design process, including MIMO array calibration, electrical/mechanical synchronization, system-level verification, and performance evaluation, are described. We present three versions of MIMO-SAR testbeds with different implementation costs and accuracies to provide alternatives for other researchers who want to implement their testbed framework. Several representative examples in various real-world imaging applications are presented to demonstrate the capabilities of the proposed testbeds and algorithms.

海洋光学系统中的时空方法

Ocean optical systems have played an increasingly important role in ocean exploration, development and monitoring. Underwater wireless optical communication and underwater lidar are two types of ocean optical systems that are rapidly developing and have good application prospects. Underwater wireless optical communication is an ideal communication option for short and medium range applications due to high speed and low latency. Underwater lidar is also a highly precise and efficient observation method in applications like deriving geographic information and target detection. However, the complex optical characteristics of seawater channels have brought challenges to the further improvement of the performance of ocean optical systems. In seawater channels, not only strong absorption and scattering, but also dynamic interference factors such as turbulence and bubbles exist in the channel. In order to deal with these challenges, on one hand, signal to noise ratio can be increased with temporal or spatial methods. On the other hand, the conversion between temporal and spatial domains is beneficial to achieving better system performance. This article reviews solutions above and the development trend of ocean optical systems is pointed out.

Ultra-wideband monopole antenna with U and L shaped slotted patch for applications in 5G and short distance wireless communications

In this paper, a monopole antenna with Ultra-wideband (UWB) characteristics is presented for applications in 5G and short-distance wireless communications. It consists of a rectangular shaped patch having truncated corners and central notch with an extended stub at top edge. Two layers of slots are engraved in the middle of the patch within which the outer layer contains four L shaped slots and the inner layer contains two face to face vertically placed U-shaped slots. A partial ground is structured with staircase slots to attain ultra-wideband response with sufficient gain and efficiency. The proposed antenna provides 124% of impedance bandwidth (2.8 GHz–12 GHz) implemented on a low-cost FR4 substrate having the electrical dimension of 0.3𝜆 × 0.19𝜆 at the low cutoff frequency. The effect of the inclusion of slots within the patch is clearly observable as it increases gain and efficiency. The proposed antenna exhibits better response with a maximum measured gain of 6.5 dBi and efficiency of 85% within the bandwidth. Near constant time delay around 1 nS and good fidelity factor of 0.8316 represents that this slotted antenna can be used for undistorted reliable signal transfer. This antenna also provides symmetrical radiation patterns with less cross-polarization effects. Therefore, this monopole antenna can be an appropriate candidate for short-range communication applications like 5G, wireless local area networks, transfer data from biomedical sensors and imaging.

Double-Solenoid Ferrite Coils for Magnetic-Field Amplification in LF and MF Bands

A design method to amplify the magnetic fields in the high-frequency (HF) band by a planar double-loop coil is known. We applied the design method to double-solenoid ferrite coils for amplifying magnetic fields in the low-frequency (LF) and medium-frequency (MF) bands. It was demonstrated that the design method can be applied to the ferrite coils operating in the LF and MF bands. Hence, the design method is applicable to magnetic field amplification without increasing the power consumption in the frequency range from the LF to HF bands. This feature is useful for reducing power consumption of short-range wireless applications such as radio frequency identification (RFID) and wireless power transmission (WPT).

Metamaterial Inspired Microstrip Offset Feed Truncated Antenna for Automotive Radar Application

A state-of-the-art design of microstrip offset feed truncated antenna for automotive radar applications operating at 24 GHz UWB band is proposed. The rectangular patch is truncated and ring shaped co directional complementary split ring resonator is imprinted on edge truncated rectangular patch to radiate in the short-range radar UWB band. The proposed antenna with Co-directional complementary split ring resonator antenna is having measurement of 5.1 x 4.65 x1.6 mm3 with operating frequency ranges from 24.6 to 30.3 GHz.This work comprises the thorough inquiries such as return loss, distribution of surface current, gain and radiation pattern. With the help of parametric analysis width of slit (z), width of feed (Wf) and length of feed (lf) the dimension of the proposed antenna is obtained. Simulation have shown decent fairness which proves the feasibility of the projected antenna for the automotive short-range RADAR application.

Multi-Layer PCB Bow-Tie Antenna Array for (77–81) GHz Radar Applications

In this article, a new wideband cavity-backed bow-tie microstrip antenna is presented for short-range 77–81 GHz radar applications. The design is based on a subarray consisting of two single elements. Each element consists of a multilayer bow-tie patch antenna surrounded by a metallic cavity to suppress the surface waves and parallel plate modes. The subarray elements are fed through a laminated waveguide with 180° phase shift. An eight-layer build-up and a new advanced multilayer PCB technology, the so-called any-layer PCB technology, is used for the fabrication. The performance of this antenna has been verified by both simulations and measurements. A bandwidth of more than 8% is achieved. The gain is 7.9 dBi, and the radiation efficiency is 70% at 79 GHz. Beam widths of 84° in the E-plane and 48° in the H-plane are obtained, which are compatible with radar requirements for short-range applications.

A 3.5-GHz Class-F Power Amplifier with Current-Reused Topology in 0.13-μm CMOS for 5G Application

In this paper, a 3.5-GHz class-F Power Amplifier with current-reused topology in 0.13-[Formula: see text]m CMOS for 5G application is presented. This proposed circuit has a two-stage structure by a current-reused topology driving to improve gain and the stability of PA. An output matching network is constructed by an open-circuited third harmonic resonator that can integrate the current and voltage waveform in the time domain adopted to improve the output power and reduce power consumption. The simulation results show that the proposed PA provides a 13[Formula: see text]dBm output power with a PAE of 50.5% and a small signal gain of 32.5[Formula: see text]dB that is higher than reported for a two-stage design in CMOS at the 3.5-GHz frequency, while the minimum output return loss ([Formula: see text]) is [Formula: see text]14.4[Formula: see text]dB with a minimum value of [Formula: see text]24.67[Formula: see text]dB. Many experiments are carried out to prove that the proposed PA has higher gain and higher efficiency compared to the traditional class-F power amplifier and is suitable for 5G short-range applications. Finally, the layout occupies a compact chip area of [Formula: see text][Formula: see text]mm2, including testing pads.

High-Resolution 160-GHz Imaging MIMO Radar Using MMICs With On-Chip Frequency Synthesizers

A high-resolution frequency-modulated continuous wave imaging radar for short-range applications is presented. A range resolution of about 1 cm is achieved with a bandwidth of up to 16 GHz around 160 GHz. In order to overcome losses and large tolerances on a printed circuit board (PCB), eight coherently coupled monolithic microwave integrated circuits (MMICs) are used, each with one transmit and receive antenna on-chip and each representing a single-channel radar system. The signals on the PCB are below 12 GHz, which facilitates fabrication and enables a design with low-cost substrates. The MMIC comprises a phase noise (PN)-optimized architecture with a fully integrated on-chip frequency synthesizer. Due to partly uncorrelated PN between the frequency synthesizer components, the noise level is increased in bistatic radar measurements between two different MMICs, which is explained by a thorough PN analysis. Time-division multiplexing is used to realize a multiple-input multiple-output system with a virtual array of 64 elements and an angular resolution better than 1.5° for the designed array. The positioning tolerances of the MMICs are included into the design resulting in a robust array design. The high-resolution radar performance is proven by imaging radar measurements of two exemplary scenarios.

Solar Power based Modeling and Monitoring of an Anti-theft luggage system through Smartphone for developing a Smart Society

The stolen of a luggage from any public transport system is a daily basics issue in almost all major areas of any country. So, the security of a packed luggage must be the key concern to all the people in our society while travelling in public transport. This paper will be purposeful to meet those challenges by installing an accelerometer sensor, Bluetooth interfaced to a microcontroller system. The senses of acceleration due to gravity in the X, Y and Z axis will be sensed by the accelerometer and an analog output will be produced by it immediately. For communicating between the system present in the luggage and the Smartphone, Bluetooth will be helpful to text the message alert signal to the owner of the luggage if there is any system violation happened from its last position of the luggage. The overall system power is taken from a solar panel of 11.32V, 0.8A as an input and the output is observed as 6V, .62A.For short range application Bluetooth module application can be useful. In case of long range GPS and GSM facilities can be installed for future benefit. The system will be beneficial to all the people in the society to make a corruption free country in this aspect.

Lubricity of Low-Viscosity Aviation Fuel JP-10 and Tribological Behaviors of Silver (Ag) Films in JP-10

To increase the thrust-to-weight ratio and reliability of gas turbine engines, conventional oil-lubricated bearings are desired to be replaced by fuel-lubricated bearings in fuel pumps. The present study aimed to examine the lubricity of low-viscosity aviation fuel JP-10 with ball-on-disc (Si3N4 ball/M50 steel disc) friction tests at ambient temperature and evaluate the tribological performance of self-lubricious silver (Ag) films while sliding in JP-10 against an Si3N4 ball. Four hundred–nanometer-thick Ag film was deposited on M50 steel by magnetron sputtering and high-current pulsed electron beam (HCPEB) was employed to alloy the as-deposited Ag film. Coefficients of friction (COFs) and wear topographies indicate that JP-10 had decent boundary and hydrodynamic lubrication performance, which was significantly better than that of deionized water but far weaker than that of professional lubricant. In JP-10, the counterpart almost immediately tore the as-deposited Ag film down from the M50 steel substrate, but the wear of the exposed steel surface was slight compared to that of bare M50 steel. Transferred Ag on the friction interface was probably responsible for the significant wear reduction but cannot effectively decrease the COF. The HCPEB-treated Ag film exhibited low friction (0.12) and effective wear protection in JP-10, but it can only function in a relatively short time in low-load conditions because of rapid wear. After wear-out, the COF rapidly rose higher than 0.2. The present work suggests that both types of Ag films are potential tribological surface modification approaches to raceways of fuel pump hybrid bearings for short-range applications.

Experimental Investigation of a Planar Antenna with Band Rejection Features for Ultra-Wide Band (UWB) Wireless Networks

The Federal Communication Commission (FCC) has authorized the use of unlicensed ultra-wide band (UWB) spectrum in the frequency range from 3.1 to 10.6 GHz for a variety of short-range applications, including wireless monitors and printers, camcorders, radar imaging, and personal area networks (PANS). However, the interference between coexisting narrowband channels and UWB signals that share the same spectrum should be avoided by designing UWB antennas with band notch characteristics. This work presents a printed monopole antenna (PMA) with slots of different shapes etched in the radiating element to obtain band rejection in the three coexisting communication bands, i.e., Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), and International Telecommunication Union (ITU). A rectangular slot is etched to reject the WiMAX band (3.01-3.68 GHz), an upturned C slot stops the WLAN band (5.18-5.73 GHz) while an inverted-U slot halts the ITU frequency band (7.7-8.5 GHz). The proposed antenna occupies a volume of 32 x 30 x 1.6 mm3 and it radiates efficiently (>90%) with a satisfactory gain (>1.95 dBi) in the unnotched UWB frequency range. The simulations are performed in High Frequency System Simulator (HFSS), while the measurements are conducted in antenna measurement facility and found in close agreement with the former.

Characterization of polymer-based piezoelectric micromachined ultrasound transducers for short-range gesture recognition applications

This paper deals with the design, simulation and characterization of polymer-based piezoelectric micromachined ultrasound transducers (PMUT) (arrays) intended for short-range gesture recognition applications. The presented process flow is fully compatible with existing flat-panel display fabrication. Finite element models were developed for the evaluation of the frequency response, deflection and acoustic pressure output of single PMUT as a function of the membrane diameter. A laser Doppler vibrometer was used to measure the frequency response, membrane velocity and displacement, as well as mode shapes of the microfabricated PMUT in air. An optical microphone was used to measure the pressure emitted by a single PMUT at various distances along the normal axis of the oscillating membrane. A strong correlation between simulations and measurement results is shown. The device geometries most suitable for short-range gesture recognition purposes are selected and the radiation pattern of square arrays is analyzed using simulations. The resonance properties of single PMUT in an array are determined using measurements. An optimized array is used to demonstrate pulse-echo measurements, and the requirements for a simple gesture recognition platform are elucidated.

Analysis and Design of an Ultra-Low-Power Bluetooth Low-Energy Transmitter With Ring Oscillator-Based ADPLL and 4$\times$ Frequency Edge Combiner

In this paper, we present an all-digital ring oscillator (RO)-based Bluetooth low-energy (BLE) transmitter (TX) for ultra-low-power radios in short range Internet-of-Things (IoT) applications. The power consumption of state-of-the-art BLE TXs has been limited by the relatively power-hungry local oscillator (LO) due to the use of LC oscillators for superior phase noise (PN) performance. This paper addresses this issue by analyzing the PN limit of a BLE TX and proposes an RO-based solution for power and cost savings. The proposed transmitter features: 1) a wideband all-digital phase-locked loop (ADPLL) featuring an $f_{\mathrm {RF}} / {4}$ RO, with an embedded 5-bit TDC; 2) a 4 $\times $ frequency edge combiner to generate the 2.4-GHz signal; and 3) a switch-capacitor digital PA optimized for high efficiency at low transmit power levels. These not only help reduce the power consumption and improve PN performance but also enhance the TX efficiency for short range applications. The TX is prototyped in 40-nm CMOS, occupies an active area of 0.0166 mm2, and consumes 486 $\mu \text{W}$ in its low-power mode, while configured as a non-connectable advertiser. The TX has been validated by wirelessly communicating beacon messages to a mobile phone.

Investigation on non‐linear aspects of pattern reconfigurable hexagon shaped planar loop antenna

A planar electronically pattern-reconfigurable antenna based on Alford-loop-type hexagon shaped radiator is presented. The antenna consists of three half-wavelength dipole radiators arranged on both sides of an FR-4 substrate. It has an overall profile of 0.47λ 0 × 0.47λ 0 × 0.012λ 0 (λ 0 free space wavelength at 2.35 GHz). The bottom ground layer is tapered to allow impedance matching. Three PIN diodes are used to control the direction of radiation pattern by switching them in a controlled manner. Thus the antenna provides reconfigurable radiation patterns in six spatial directions with by switching three PIN diodes in ON and OFF states. The antenna has a measured impedance bandwidth of 2.35-to 2.45 GHz (4.16% fractional Bandwidth) and steers the beam in six directions 0°, 60°, 120°, 180°, 240°, and 300° covering the entire azimuthal plane. The antenna offers a maximum measured gain of 2.66 dB with simulated efficiency over 75%. Further, an investigation of non-linear effects due to PIN diodes shows that the antenna operates in the linear region up to an input power level of 27 dBm where the strength of received spurious harmonic and intermodulation signals is negligible. It makes the antenna suitable for indoor and short-range communication applications in the 2.4 GHz band.

Accurate and Robust CW-LFM Radar Sensor: Transceiver Front-End Design and Implementation

This paper outlines the design and implementation of a continuous-wave linear-frequency-modulated sensor for short-range radar applications. Low-cost technologies have been selected to implement the sensor. It was integrated on a 0.127-mm-thin ceramic substrate using the miniature hybrid microwave integrated circuit technology. Two 16-dBi gain $8\times 2$ patch antenna arrays are implemented in the transmitter and receiver modules. The receiver is a six-port homodyne quadrature down-converter. The integrated power detectors are fabricated using HSCH-9161 Schottky diodes. The complete sensor, in the metallic fixture, measures $35\times 45$ mm. The performance of the sensor to detect a target range and velocity is validated using system simulations and measurement systems on a test bench. System simulations use computer models based on S-parameter measurement results. Measurements show that an accuracy of $\pmb {\pm } 16.23~ {\mu }\text{m}$ can be achieved with the sensor over a range of 15cm. To precisely measure the six-port radar accuracy, due to our RF laboratory capabilities, this result is obtained by changing the electrical length, instead of varying the physical distance.

Banwidth Reconfigurable Filtering Antenna

A microstrip bandwidth reconfigurable filtering antenna is implemented by simply tuning the transmission zeroes. The proposed filtering antenna is developed by integrating the filter characteristics into the 50 Ω microstrip feed line of the antenna through two independent coupled resonators. The energy coupling between the transmission line and the planar loop resonator and dual F shaped resonator generates the transmission zeroes. These transmission zeroes at specified lower frequencies are generated in order to provide better selectivity over the edges of the pass band to promote high suppression of interferences. The varactor diodes are explicitly loaded at distinct locations in the resonators to achieve bandwidth reconfiguration. The two transmission zeros are tuned between 1.6–1.9 GHz and 2.1–2.42 GHz respectively by varying the capacitance of the two varactor diodes with percentage bandwidth of 17.1% and 14.1% respectively to support mobile and wireless short range applications. The proposed filtenna provides insertion loss less than 3 dB with good impedance matching below 15 dB.

Time‐domain properties of dual‐band‐notched circle‐like slot antenna in indoor environments

A previous investigation of a modified circle-like slot antenna with dual-band-notched properties is extended. Frequency-domain characteristics have proved that the proposed antenna has very wide impedance bandwidth and shows good radiation characteristics. In this Letter, time-domain properties in terms of the antenna pulse response and power spectral density are investigated. Moreover, a study of indoor propagation channel characteristics when the proposed antenna is applied as transmitter and the receiver antenna is presented. A frequency-domain measurement setup and a sub-band divided ray tracing method are applied to measure and simulate the ultra-wideband indoor channel characteristics. The results show that the proposed antenna has also good time-domain characteristics and it is suitable for indoor and short range applications.

Toward Millimeter-Wave Joint Radar Communications: A Signal Processing Perspective

Synergistic design of communications and radar systems with common spectral and hardware resources is heralding a new era of efficiently utilizing a limited radio-frequency (RF) spectrum. Such a joint radar communications (JRC) model has advantages of low cost, compact size, less power consumption, spectrum sharing, improved performance, and safety due to enhanced information sharing. Today, millimeter-wave (mmwave) communications have emerged as the preferred technology for short distance wireless links because they provide transmission bandwidth that is several gigahertz wide. This band is also promising for short-range radar applications, which benefit from the high-range resolution arising from large transmit signal bandwidths. Signal processing techniques are critical to the implementation of mm-wave JRC systems. Major challenges are joint waveform design and performance criteria that would optimally trade off between communications and radar functionalities. Novel multiple-input, multiple-output (MIMO) signal processing techniques are required because mm-wave JRC systems employ large antenna arrays. There are opportunities to exploit recent advances in cognition, compressed sensing, and machine learning to reduce required resources and dynamically allocate them with low overheads. This article provides a signal processing perspective of mm-wave JRC systems with an emphasis on waveform design.