Effective Radiated Power Research Articles

Discrete Bio-Hazard Model of EM Radiation for Crowded People

This study investigates the behaviour of electromagnetic (EM) waves in densely populated environments using a Multicomponent Discrete Propagation Model (MCDM). Our analysis focuses on four critical parameters: Specific Absorption Rate (SAR), Electrical Field, Skin Depth, and Effective Radiated Power (ERP) by working on crowd densities and frequencies relevant to mobile technologies. This study is the first to employ a Propagation Model for such an analysis, offering a novel approach. Through comprehensive simulations, we explore how variations in electrical field strengths impact SAR, skin depth, and ERP. The results are compared to established safety limits for whole-body SAR exposure, providing valuable insights for guidelines. This research aims to contribute to designing future electronic devices that minimize overall RF emissions. This innovative approach has the potential to improve public confidence in the safety of wireless technologies significantly

Спектральные характеристики плазменных волн ионосферы при возбуждении мощными КВ-радиоволнами на частотах излучения вблизи гирогармоник электронов и критической частоты слоя F2

We present the result of the studies into characteristics of high-latitude ionospheric F-region longitudinal plasma waves (Langmuir and ion-acoustic), caused by the impact of powerful HF radio waves of ordinary (O-mode) or extraordinary (X-mode) polarization of the EISCAT/Heating facility, Tromsø, Norway. The powerful HF radio waves on October 20, 2012 and February 26, 2013 were emitted in the direction of the magnetic zenith with a step change in the effective radiation power (ERP). The radiation frequency fH of the EISCAT/Heating facility on February 26, 2013 was close to the F2-layer critical frequency foF2 (fH/foF2~1) and exceeded the electron gyroresonance frequency fH>5fce. On October 20, 2012, the conditions fH/foF2~0.85–0.95 and fH<6fce were fulfilled. Analysis of EISCAT measurements of an incoherent scatter radar (ISR) at a frequency of 930 MHz, spatially aligned with the heating facility for radiation conditions ERP<200 MW, has shown that parametric decay instabilities are excited at the ionospheric heights where the pump frequency is close to the plasma Langmuir frequency, fH≈fPL. We have studied peculiarities of excitation of the decay parametric instabilities as a function of height in the ionosphere and pump wave polarization, the ratios between fH and foF2, and also fH and nfce.

Spectral features of ionospheric plasma waves excited by powerful HF radio waves radiated at frequencies near electron gyroharmonics and F2-layer critical frequency

We present the result of the studies into characteristics of high-latitude ionospheric F-region longitudinal plasma waves (Langmuir and ion-acoustic), caused by the impact of powerful HF radio waves of ordinary (O-mode) or extraordinary (X-mode) polarization of the EISCAT/Heating facility, Tromsø, Norway. The powerful HF radio waves on October 20, 2012 and February 26, 2013 were emitted in the direction of the magnetic zenith with a step change in the effective radiation power (ERP). The radiation frequency fH of the EISCAT/Heating facility on February 26, 2013 was close to the F2-layer critical frequency foF2 (fH/foF2~1) and exceeded the electron gyroresonance frequency fH>5fce. On October 20, 2012, the conditions fH/foF2~0.85–0.95 and fH<6fce were fulfilled. Analysis of EISCAT measurements of an incoherent scatter radar (ISR) at a frequency of 930 MHz, spatially aligned with the heating facility for radiation conditions ERP<200 MW, has shown that parametric decay instabilities are excited at the ionospheric heights where the pump frequency is close to the plasma Langmuir frequency, fH≈fPL. We have studied peculiarities of excitation of the decay parametric instabilities as a function of height in the ionosphere and pump wave polarization, the ratios between fH and foF2, and also fH and nfce.

A 22-m Operation Range Semi-Passive UHF RFID Sensor Tag With Flexible Thermoelectric Energy Harvester

This article presents a wireless temperature sensor tag able to work in both fully passive mode and in semi-passive mode when assisted by a flexible thermoelectric generator (TEG). The sensor tag consists of an EPC C1G2/ISO 18000-6C ultrahigh-frequency (UHF) radio frequency identification (RFID) integrated circuit (IC) connected to a low-power microcontroller unit (MCU) that samples and collects the temperature from a digital temperature sensor. With a temperature gradient as low as 2.5 °C, the test results show that the TEG provides an output power of 400 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$ </tex-math></inline-formula> W with an output voltage of 40mV. Bymeans of an up-converter in order to boost the TEG output voltage, this harvester supplies the power required to the sensor tag for a 2-conv/s data rate in semi-passive mode. Moreover, when the tag operates in semi-passive mode, a communication range of 22.2 m is measured for a 2-W effective radiated power (ERP) reader. To the best of our knowledge, the proposed TEG-assisted sensor tag shows the longest communication range and the only one that provides stable external power at low-temperature gradients. The measured performance and the chosen architecture allow using the wireless sensor in multiple industrial or biomedical applications.

Optimization of ground plane antenna gain by increasing the inductance of loading coil based on silver material

To overcome the attenuation due to signal distortion in the telex model antenna transmitter, the copper and silver coil loading materials for gain have been tested. The parameters include standing wave ratio (SWR) value≈1, the antenna impedance (ZL), return loss (RL), reflection coefficient (ρ) which measured the bandwidth (BW) and quality factor (Q). In this experiment a telex model ground antenna is used, a coaxial feeder cable with 50 Ω and an operating frequency of 144.280 MHz was used. The feeder cable is tuned to approximate pure resistive with minimum impedance to reach maximum resonance frequency. The field strength effective radiated power (ERP) is measure based on 4 measurement points which has different distances within 100 km areas. The results show that the antenna based on copper loading coil (CLC) has a bandwidth is BW=5.166 MHz and Q=27.929, moreover, the silver loading coil (SLC) antenna the bandwidth is BW=4.500 MHz and Q=32.062. Therefore, SLC material could provide a good reduction in attenuation of signal distortion when signal radiation occurs from the antenna to the air.

Analysis of ADAS Radars with Electronic Warfare Perspective.

The increasing demand in the development of autonomous driving systems makes the employment of automotive radars unavoidable. Such a motivation for the demonstration of fully-autonomous vehicles brings the challenge of secure driving under high traffic jam conditions. In this paper, we present the investigation of Advanced Driver Assistance Systems (ADAS) radars from the perspective of electronic warfare (EW). Close to real life, four ADAS jamming scenarios have been defined. Considering these scenarios, the necessary jamming power to jam ADAS radars is calculated. The required jamming Effective Radiated Power (ERP) is −2 dBm to 40 dBm depending on the jamming scenario. These ERP values are very low and easily realizable. Moreover, the effect of the jamming has been investigated on the radar detection at radar Range Doppler Map (RDM) and 2-Dimensional Constant False Alarm Rate (2D-CFAR). Furthermore, the possible jamming system requirements have been investigated. It is noted that the required jamming system will not require high-end technology. It is concluded that for the security of automotive driving, the ADAS radar manufacturer should consider the intentional jamming and related Electronic Counter Countermeasures (ECCM) features in the design of ADAS radars.

Simultaneous Action of X- and O-Mode HF Pump Waves on the High-Latitude Upper (F-Region) Ionosphere at EISCAT

We report experimental results from multi-instrument diagnostic tools related to phenomena in the high latitude ionosphere F-region, induced by the simultaneous action of powerful extraordinary (X-mode) and ordinary (O-mode) polarized HF radio waves at EISCAT (European Incoherent SCATter) during magnetically quiet background geophysical conditions. HF pump waves were injected towards the magnetic zenith at a frequency of 5.423 MHz, which was just below the critical frequency of the F2 layer when the excitation of X- and O-mode phenomena was possible. In the course of the experiment, the effective radiated power (ERP) of the X-mode wave was 130.5 MW, while the portion of the O-mode ERP was 29.9 MW (about 20% of the full ERP). It was found that simultaneous action of the X- and O-mode pump waves lead to the excitation of effects typical for both X- and O-mode HF pump waves. Namely, the excitation of small-scale field-aligned irregularities due to the thermal parametric (resonance) instability and a downshifted maximum (DM) component in the wideband stimulated electromagnetic emission (WSEE) spectra, typical for the O-mode HF pumping, was observed, together with multiple ion gyro-harmonic structures in the narrowband stimulated electromagnetic emission (NSEE) spectra. These latter results were recorded at a large (more than 1000 km) distance from the EISCAT/heating facility, typical only for an X-mode HF pumping. The results obtained are compared with “pure” O-mode heating and discussed in detail.

Theoretical Analysis of Parameter Optimization for Lower-Ionosphere Excitation ELF/VLF Waves Based on Chirp-BOK Modulated Heating

To improve the anti-interference for ELF/VLF communication based on modulated heating lower-ionosphere, chirp spread spectrum technology with strong anti-interference is combined with square wave amplitude modulation, a novel method of chirp-BOK modulated heating lower-ionosphere is proposed in this paper. On this basis, to improve the radiation efficiency of ELF/VLF, the effects of heating parameters (effective radiation power, pump frequency, polarization mode, modulation frequency, duty cycle, and bandwidth) on the radiation efficiency of ELF/VLF were analyzed. The results show that the radiation amplitude of ELF/VLF increases with the increase of effective radiation power, while the radiation efficiency increases first and then decreases; the X-mode is better than the O-mode; the radiation intensity of ELF/VLF decreases with the increase of pump wave frequency from 4MHz to 10MHz; the ELF/VLF equivalent dipole moments increase with the rise of modulation frequency from 500Hz to 5kHz; with the change of duty cycle from 10% to 90%, the dipole moments first increase and then decrease, and the optimal range of duty cycle is 40% to 70%; with the increase of bandwidth, the dipole moments are unchanged. Furthermore, the ELF/VLF dipole moments of square wave amplitude modulated heating ionosphere is unchanged before and after the chirp spread spectrum.

Characterization of Artificial, Small-Scale, Ionospheric Irregularities in the High-Latitude F Region Induced by High-Power, High-Frequency Radio Waves of Extraordinary Polarization

The results of experimental studies of characteristics of artificial, small-scale, ionospheric irregularities in the high-latitude ionospheric F region caused by the controlled injection of high-power, high-frequency (HF) radio waves of extraordinary polarization (X mode) are presented. The experiments were carried out at the HF European Scientific Association (EISCAT)/Heating complex (Tromso, northern Norway (69.6° N, 19.2° E)) in a wide range of heating frequencies (4–8 MHz) with an effective radiation power of 100 to 700 MW. It is shown that the generation of irregularities upon X heating occurs in the regular F region of the ionosphere under quiet magnetic conditions at heating frequencies both lower and higher than the critical frequency of the F2 layer. The rise and relaxation times of the irregularities, as well as the threshold powers of their excitation are determined. It is ascertained that the characteristics of irregularities upon X heating strongly depend on the heating frequency, the relationship between the heating frequency and the critical frequency of the F2 layer, and the conditions preceding the start of the heating cycle (“cold” start in the first X-heating cycle or subsequent X-heating cycles). The characteristics of irregularities upon exposure of the high-latitude ionospheric F region to high-power long radio waves of extraordinary (X mode) and ordinary (O mode) polarization are compared.

고출력 GPS 재방송 교란을 위한 무선 교란 장치

In this study, we propose a wireless meaconing jamming system for use in high-power GPS meaconing. The purpose of GPS meaconing is to ensure that the target GPS receiver calculates the intended jammer position by repeating the jammer-received GPS signal. In this case, because the received and transmitted signals have the same frequency, the front–back Ratio(FBR) of the antenna should be −160 dB when the effective radiated power(ERP) is 1 W(30 dBm). Thus, the meaconing jammer can malfunction by reducing the back-lobe level of the antenna when the receiver and transmitter are located in a jammer device. In general, the receiver and transmitter are isolated by the time-division or duplex-communication method in order to eliminate reception/transmission interference; however, this performance is still limited. Thus, we designed a wireless meaconing jammer to eliminate reception/transmission interference by long-distance separations.

Means for generating ultra-wideb and radio-frequency emissions with semiconductor field generators

The paper considers the perspective of using powerful semiconductor subnanosecond electrical pulse generators as radiation modulators. We give the data on determining the amplitude-time and spectral radiation parameters of a synchronous active antenna array, the angular divergence of the array radiation. We also estimate the efficiency of converting the electric excitation energy of the antennas into the energy of the directed ultra-wideband radiation in the main directional lobe. Findings of the research show that the effective peak radiation power of the terawatt level is reached at the excitation power of the gigawatt level, and the effective average radiation power of tens of megawatts is achieved with the primary power consumption of modulators of tens of kilowatts.

An Efficient Processing Architecture for Range Profiling Using Noise Radar Technology

The importance of high resolution range profiles (HRRPs) for radar applications like tracking or classification is well known. In the scientific literature several approaches have been investigated to obtain HRRPs from wideband radar signals. Recent works show that noise radar waveforms can be exploited in this sense due to their high resolution and low peak to sidelobe ratio (PSLR) properties. However their use can cause some issues in applications where long time integrations are required, e.g., in the presence of a low effective radiated power (ERP) transmitter: recording the reference signal in this case would be difficult due to the big quantity of data. This work proposes a real time digital processing schematic based on linear feedback shift registers (LFSRs) which is very flexible and has a low computational burden: its internal state can be easily controlled and reproduced in reception, where a multichannel correlator is exploited as matched filter. The resulting signal, compared to typical “pulse compression” and noise radar waveforms, shows similar performances but a lower order of complexity in terms of real time generation and reception.

Theory of very low frequency/extra low frequency radiation by dual-beam beat wave heating ionosphere

At high latitudes, the proposed dual-beam beat wave method has become the focus of research because of its relative amplitude modulation method. The very low frequency/extra low frequency(VLF/ELF) radiation intensity does not depend on the background of the current, and can be used as an importantparameter of VLF/ELF radiation in poor background conditions. As for the background of weak natural current in middle and low latitude regions, the amplitude modulation method stimulates the VLF/ELF radiation effect poorly, therefore, at the low latitudes, the relative amplitude modulation method, dual-beam beat waves method may be more effective. In this paper, according to the pondermotive nonlinear heating theory in the upper ionosphere, a simulation model is presented about VLF/ELF radiation generated by dual-beam heating of the ionosphere via beating waves. This model is validated by calculations and the available experimental parameters. Based on this model, a comprehensive analysis is performed, involving the dependences of radiation intensity on various parameters such as latitude, effective radiation power(ERP), heating frequency, polarization, experimental times, and beating frequency difference. Then, we compare the dual-beam beat wave method with the amplitude modulation in stimulating VLF/ELF signals in the low and moderate latitude regions. Several conclusions are drawn as follows. First, the increases of geomagnetic declination and ERP of the heating facility may lead to a considerable improvement in radiation efficiency. Second, the X-mode polarization is more efficient for radiation than the O-mode polarization. Third, the most remarkable radiation effect may appear at winter night. The optimal heating frequency and the beating wave difference could be found under certain conditions. Stimulations of VLF/ELF radiation with the dual-beam beating wave method are more effectivethan the available amplitude modulation, the difference in VLF/ELF radiation intensity between the two methods is about 10 dB.

Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags.

A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919–923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for ‘place and tag’ application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP).

Aspects regarding the use of the INFREP network for identifying possible seismic precursors

In the last decades, one of the main research directions in identifying seismic precursors involved monitoring VLF (Very Low Frequency) and LF (Low Frequency) radio waves and analysing their propagation characteristics. Essentially this method consists of monitoring different available VLF and LF transmitters from long distance reception points. The received signal has two major components: the ground wave and the sky wave, where the sky wave propagates by reflection on the lower layers of the ionosphere. It is assumed that before and during major earthquakes, unusual changes may occur in the lower layers of the ionosphere, such as the modification of the charged particles number density and the altitude of the reflection zone. Therefore, these unusual changes in the ionosphere may generate unusual variations in the received signal level.The International Network for Frontier Research on Earthquake Precursors (INFREP) was developed starting with 2009 and consists of several dedicated VLF and LF radio receivers used for monitoring various radio transmitters located throughout Europe. The receivers’ locations were chosen so that the propagation path from these VLF/LF stations would pass over high seismicity regions while others were chosen to obtain different control paths.The monitoring receivers are capable of continuously measuring the received signal amplitude from the VLF/LF stations of interest. The recorded data is then stored and sent to an INFREP database, which is available on the Internet for scientific researchers. By processing and analysing VLF and LF data samples, collected at different reception points and at different periods of the year, one may be able to identify some distinct patterns in the envelope of the received signal level over time. Significant deviations from these patterns may have local causes such as the electromagnetic pollution at the monitoring point, regional causes like existing electrical storms over the propagation path or even global causes generated by high-intensity solar flares. As a consequence, classifying these perturbations and minimizing them (when possible) would represent an important step towards identifying significant pattern deviations caused by seismic activities.Taken into consideration some of the issues mentioned above, this paper intends to present some aspects meant to improve the overall performance of the existing INFREP network. The signal-to-noise ratio improvement of the monitoring receiver may be achieved by relocating the antenna (or even the entire monitoring system if possible) in areas with less electromagnetic pollution within the VLF and LF bands. Other solution may involve replacing the existing electric “whip” antennas with magnetic loop antennas.Regarding the measuring method, long-term averaging of the received signal to reduce the electromagnetic noise should be carefully applied. If the averaging time is too long, there is a risk that, during a seismic event, the details of the received signal envelope would be lost. Moreover, this may reduce the possibility of making correlations between the monitored stations and INFREP receivers in case of sudden ERP (Effective Radiated Power) variations of the VLF/LF stations. For the same reason, the time synchronization of the recorded data using (for instance) GPS technology is highly recommended.Other aspects related to the overall performance improvement of the INFREP network consist of monitoring other VLF/LF stations such as the Krasnodar station (south of Russia), part of the ALPHA/RSDN-20 VLF navigation system, or the 77.5kHz DCF77 time signal transmitter (near Frankfurt am Main, Germany). Moreover, the installation of a new reception point in Romania (near Cluj-Napoca) for monitoring the Vrancea area (within the Carpathians Mountains) and the Adriatic region will provide complementary scientific data within the network.

Telescope Array Radar (TARA) observatory for Ultra-High Energy Cosmic Rays

Construction was completed during summer 2013 on the Telescope Array RAdar (TARA) bi-static radar observatory for Ultra-High Energy Cosmic Rays (UHECR). TARA is co-located with the Telescope Array, the largest “conventional” cosmic ray detector in the Northern Hemisphere, in radio-quiet Western Utah. TARA employs an 8MW Effective Radiated Power (ERP) VHF transmitter and smart receiver system based on a 250MS/s data acquisition system in an effort to detect the scatter of sounding radiation by UHECR-induced atmospheric ionization. TARA seeks to demonstrate bi-static radar as a useful new remote sensing technique for UHECRs. In this report, we describe the design and performance of the TARA transmitter and receiver systems.

위성항법시스템을 위한 항재밍 기술 분석

위성항법시스템을 위한 항재밍 기술 분석

Theory and Numerical Modeling of Under‐Dense Heating With Powerful X‐Mode Pump Waves

AbstractBased on the mechanisms of both electron cooling and heating in the ionosphere, a theoretical simulation model of under‐dense heating by X‐mode waves is constructed. And this model is verified by simulating the known experimental results. Using this model, we analyze the influences of heating parameters and the ambient ionosphere on the heating effects. The results show that in the under‐dense heating ionosphere by powerful X‐mode wave, the heating effects are enhanced when the effective radiated power (ERP) increases, and weakened as the heating frequency increases. The lower the electron temperature and the smaller the density, the stronger the heating effects are. Finally, some applications of under‐dense heating by X‐mode waves are analyzed.

Carrier Mobile base Station for Wireless Sensor Network using Particle Swarm Optimization

Wireless Sensor Network is becoming progressively important and challenging research area. A wireless Sensor Network consists of spatially distributed sensor nodes to monitor physical and environmental condition to pass their data through the network to a base station. Base Station in a Sensor Network is usually a node with high processing power, high storage capacity and the battery used can be rechargeable, the base station can be utilized to collect data from each sensor node in the sensing area by moving closer to the transmitting node. Base station design parameters, such as base station antenna height and effective radiated power (ERP) are determined by trading-off two design objectives: (a) coverage and (b) economic efficiency which are found to be in conflict. It is evaluated that the conventional approach is unable to optimize these design objectives simultaneously while with PSO algorithm, it is possible to find a set of values for base station antenna height and ERP that trade-off between cell coverage and its economic efficiency. In the proposed method, the fitness function is formed by taking weighted sum of two design objectives as mentioned. A homogeneous traffic environment is evaluated with the proposed technique. This paper also focuses on energy efficient protocol for the movement of mobile base station using PSO method in wireless sensor Network. Simulation results demonstrate that the proposed protocol can improve the network lifetime, data delivery and energy consumption compared to the existing energy efficient protocol developed for this network.

TARA: Forward-scattered radar detection of UHECR at the telescope array

Increased event statistics will be required to definitively answer the question of the origin(s) of Ultra-High Energy Cosmic Rays (UHECR). Using current technologies however, achieving the necessary statistics may be financially and practically impossible. We describe the status and plans of the TARA project, an effort to detect Ultra-High-Energy Cosmic Rays by their forward scattered or “bistatic” radar signature. Bistatic radar holds promise as a new remote sensing technique for UHECR, without the duty cycle limitations of nitrogen fluorescence detectors. Such a technique could prove key in advancing the study of UHECR beyond the constraints of the current generation of cosmic ray observatories. TARA consists of a low-VHF television transmitter illuminating the air above the Telescope Array (TA), and a set of radio receivers on the far side of TA approximately 50 km distant from the transmitter. We have collected radar data since April 2011 using a 2 kW transmitter at 54.1 MHz. Recently, we received permission to increase our broadcast power to 40 kW and our effective radiated power (ERP) to 6 MW. On the receiver end, we are employing software-defined radio receivers and developing real-time trigger algorithms based on the expected air shower radar echo. In addition to presenting an overview of the project status and future plans, we will present the most recent results of searches for coincidences between radar echoes and Telescope Array air shower events.