Received Power Level Research Articles

Radar near-field sensing using metasurface for biomedical applications

Metasurfaces, promising technology exemplified by their precise manipulation of incident wave properties and exquisite control over electromagnetic field propagation, offer unparalleled benefits when integrated into radar systems, providing higher resolution and increased sensitivity. Here, we introduce a metasurface-enhanced millimeter-wave radar system for advanced near-field bio-sensing, underscoring its adaptability to the skin-device interface, and heightened diagnostic precision in non-invasive healthcare monitoring. The low-profile planar metasurface, featuring a phase-synthesized array for near-field impedance matching, integrates with radar antennas to concentrate absorbed power density within the skin medium while simultaneously improving the received power level, thereby enhancing sensor signal-to-noise ratio. Measurement verification employs a phantom with material properties resembling human skin within the radar frequency range of 58 to 63 GHz. Results demonstrate a notable increase of over 11 dB in near-field Poynting power density within the phantom model, while radar signal processing analysis indicates a commensurate improvement in signal-to-noise ratio, thus facilitating enhanced sensing in biomedical applications.

A Compact, Low-Profile, Broadband Quasi-Isotropic Antenna for Non-Line-of-Sight Communications

A single-feed broadband quasi-isotropic antenna was designed for non-line-of-sight (NLOS) wireless sensor networks. The proposed antenna is based on a combination of fork-shaped crossed dipoles. It shows the broadband of quasi-isotropic radiation characteristics with high radiation efficiency. The electrical size ka of the proposed antenna is 0.94 with respect to its lower operating frequency. Its profile is also extremely thin at 0.0015λ. The impedance is matched from 1.8 to 4.3 GHz, or an 81.9% fractional bandwidth, whereas the maximum gain deviation ranging from 6.2 to 9.2 dB for the quasi-isotropic radiation is achieved from 1.8 to 3.6 GHz with a 10 dB criterion, which is close to the impedance bandwidth. The performance from the computed expectations is verified, as it shows a gain deviation of 8.4–9.8 dB from 1.9 to 3.3 GHz with an 80% fractional impedance bandwidth. The proposed antenna also shows good spatial coverage of circular polarization at high frequencies. Lastly, the received power level performance of the proposed antenna is tested under the NLOS condition, which shows a higher level compared to the linearly polarized, broadband omni-directional monopole antenna.

Implementation of Spectrum Sensing Algorithm Based on Television White Space Scenarios for Spectrum Aggregation Applications

With the proliferation of mobile devices and diverse mobile applications, wireless operators are experiencing phenomenal growth in the demand for mobile services around the world. These demands have led to the technological responses such as the advancement in radio access, coding and modulation schemes as well as spectrum (carrier) aggregation and cognitive radio capabilities. The aspect of spectrum or carrier aggregation uses cognitive radio technology that implements the dynamic spectrum access for spectrum utilization by sensing and using the underutilized spectrum on co-primary basis without interference to the primary users. In this work, an energy-based, non-parametric TVWS spectrum sensing algorithm was implemented in MATLAB environment. The developed sensing algorithm was aimed at finding free TVWS frequency channel(s) that would be used during spectrum aggregation of channels from TVWS and LTE-A spectrums. The chosen free channel would be configured as the component carrier two (CC2) at the configuration management platform of the TVWS eNode B. The result showed the instantaneous TV channels statuses; free, busy and interfered by computing the PSD expressed in dB while the estimated received power level in dBm for free channels was computed for the UHF range from channel 21 through channel 69. The detectable TV signals’ threshold value was set at -114 dBm. In the ten simulation five cycles carried out, the developed algorithm instantaneously selected channels: 68,34,48,60 and 28 corresponding to the centre (carrier) frequencies of 850MHz, 578MHz, 690MHz, 786MHz and 530MHz, would be dynamically configured as the component carrier two (CC2) in the TVWS eNode Bs during spectrum aggregation process.

Revisiting HF Ground Wave Propagation Losses Over the Ocean: A Comparison of Long‐Term Observations and Models

[ Understanding variations in the received power levels for land-based high frequency radar systems is critical to advancing radar-based estimates of winds and waves. We use a long-term record of one-way high frequency radar power observations to explore the key factors controlling propagation losses over the ocean. Observed propagation loss was quantified using an 8-month record of radio frequency (RF) power from a shore-based transmitter, received at two locations: an offshore tower and a nearby island. Observations were compared to environmental factors such as wind speed and air temperature as well as models of path loss incorporating smooth and rough surface impedances and varying atmospheric properties. Significant differences in the observations at the two sites existed. One-way path loss variations at the tower, a wavelength above mean sea level, were closely related to atmospheric forcing, while variations at the distant island site were dominated by wind-driven surface gravity wave variability. Seasonal variability in ocean conductivity had no significant effect on over-ocean path losses. Simplistic analytical models of path loss were found to have more skill than either ground wave propagation models or more complex numerical models of field strength in matching the observations, due in part to under-observation of the atmosphere but also the differences in rough surface impedance between models of ocean waves. ]

ANALISIS PERBANDINGAN LINK BUDGET UNTUK MENGHITUNG PATH LOSS PADA DAERAH URBAN DAN SUBURBAN MENGGUNAKAN METODE OKUMURA HATTA

As time goes by, the development of cellular communication technology is increasing, this is related to the increasing need for cellular communication. Cellular communication propagation media uses air, propagation between sender and receiver can cause propagation losses and affect the quality of communication. Therefore we need a communication network planning. In wireless communication planning requires link budget calculation. The link budget calculation is useful for cost efficiency and building a quality communication system. Therefore, in this study, link budget calculations in urban and sub-urban areas were made using the Okumara Hatta method and simulations using Matlab software. In this study using data from various sources. The data is used to calculate the path loss value and the received power level. From the results of research using the Okumara-Hatta method, it proves that the greater the distance or distance of the MS (mobile station) to the BTS (Base Transceiver Station), the greater the path loss experienced. The carrier frequency, BTS height, and MS height also affect the starting point of the path loss.

Long Term Evolution Network Planning Using The Backhaul Microwave Link in The Village Wangunharja Lembang District

Wangunharja village has an area of 832 ha and a population of 8256. In this village, 4G LTE network coverage still does not reach the entire region. Therefore, LTE network planning is needed to expand coverage in the area. This study was carried out by analyzing and planning LTE networks use microwave backhaul in Wangunharja Village. The first step is to check the quality of the signal along the main line of the village. Then, plan for capacity and LTE network coverage to determine the number of sites needed. Next, microwave backhaul planning is carried out with work frequency based on the distance of the backhaul link. Based on the LTE network planning the calculations show that two sites are required to cover the Wangunharja Village area. Furthermore, planning simulations are carried out using simulation software, and the values of the three parameters measured have met the operator's KPI standards. With a microwave link distance of 2.87 km, the operating frequency of the microwave antenna operates at 11 GHz.The results of microwave link calculations and simulations for the value of the received power level are -18.95 dBm, with a gain antenna of 45.8 dBi obtained fading margin of 49.04 dBm so that the availability value or level of availability in one year is 99.999%.

Dual-Frequency Retrodirective Antenna Array With Wide Dynamic Range for Wireless Power Transfer

This letter presents a dual-frequency heterodyne retrodirective antenna (RDA) array with relatively large frequency ratio between receiving and transmitting for adaptive tracking in far-field wireless power transfer systems. The proposed RDA consists of an eight-channel radio frequency mixing, amplify chain and two 1 × 8 circularly polarized arrays with different operation frequency and orthogonal polarizations, receiving at 3.8 GHz with right-hand circular polarization and transmitting at 5.8 GHz with left-hand circular polarization, respectively. For received power levels from −80 to −40 dBm, each chain outputs with consistent phase and stable power about 29 dBm brought by automatic gain control and compensation phase shifter. It can transmit reversely along the direction of beacon signal from near to far distance. High system isolation is achieved through inherent isolation of different frequencies and orthogonal polarizations of the T/R arrays. Monostatic and bistatic measurements are taken, and measured results verify that the proposed RDA is of far-field tracking capability to receive and transmit from −40° to 40°.

Time-Switching Symmetric Transmitter Array to Increase Sweet Region for Far-Field Wireless Power Transmission Under Receiver Rotation and Location Variation

For wireless power transfer using linear-polarized transmitter (TX) and receiver antennas, the rotation and movement of receiving antenna cause received power variation. The received power pattern is proposed to describe the received power variation from a specific TX antenna under receiver rotation. By placing the peak of the received power pattern of additional TX antennas in null directions of the previous TX antenna, received power variation due to rotation can be compensated. With symmetrically placed TX antennas, the power variation due to location variation can be compensated. This article proposes a time-switching symmetric transmitting array combining both techniques to increase the sweet region for far-field wireless power transfer under rotation and location variation. A sweet region is an area in the 2-D case or volume in the 3-D case, which is defined as an area or a volume inside the TX array that can get guaranteed minimum received power under rotation. The received power calculation using the Friis equation with short dipole antenna pattern shows that a symmetric TX array can achieve a larger sweet region than an asymmetric TX array under the same total transmitted power. The efficiency for the receiver at the origin is 1/2 at the 2-D case and 1/3 at the 3-D case. In the experiment, a linear-polarized TX array at 915 MHz with monopole receiver antenna and power detector is used as the receiver to measure received power under rotation and location variation. Measurement results at 2-D and 3-D cases confirm the received power level predicted by calculation using the Friis equation. The power budget calculation for wirelessly powering a sensor module attached on a bee inside a beehive using the proposed 3-D TX array shows that it is feasible to deliver sufficient power to the sensor module regardless of the orientation and location of the bee inside the beehive.

Analysis of Vsat Gyro performance based on the power level of the antenna receiver on the Pelni ship

The satellite communication system that is used for ship communication in Indonesian waters is expected to transmit real time data at any time under any conditions. However, currently, the Vsat Gyrsoscope antenna that is installed on the Pelni ship still uses the Ku band frequency. This frequency band is very susceptible to rain attenuation. Vsat Gyro will automatically search for satellites that cover it. Only when it is raining and the ship is moving towards the port, is there a decrease in the receiving power level. SNR and power and C/N will drop. Therefore, it is necessary to do an analysis to overcome this problem so that it is not disconnected during the transmission. This study conducted an analytical study to validate the analytical predictions of phasing the vsat power signal level on the pelni ship to maintain communication during sea operations, which are included in TKT 3 (three). The tools used in the measurement are vsat modem, PRTG application, laptop, RJ 45 cable, and Spectrum Analyzer. By optimizing the calculation of the margin link budget, the calculation of Qos and the parameters vsat Eb/No, C/N and SNR when adjusted to the operating conditions of the ship with high rain intensity so that communication can continue to run even when the worst conditions can be maintained properly.Â

Communications Channel Characteristics Due to Aircraft Body Blockage in Urban Air Mobility

In urban air mobility, a large piece of conductive airframe with extended carbon fiber blades is an obstructing factor for aircraft-ground communications. In this letter, we conduct outdoor measurements of propagation channels on a giant multi-rotor drone. Channel impulse response and received power level are recorded and utilized for investigation, from which root mean square delay spread and frame outage probability are derived. These measurement results demonstrate that high speed rotating propellers and the airframe of the urban air mobility (UAM) have obvious negative impact on the communications link. The position of antennas should be chosen properly to reduce the blocking effect.

An Extra Low-Mass Harmonic Radar Transponder for Insect Tracking Applications

The design, construction, and performance of a harmonic radar transponder with a total mass of less than 500 μg is presented. The transponder is intended for insect tracking applications and consists of very fine wire and a small Schottky diode. It is designed for fundamental and harmonic frequencies of 10 GHz and 20 GHz, respectively. Compared to existing harmonic radar transponders, this transponder is easy to construct because the loop inductor can be implemented with a simple bend in the dipole conductor without degrading performance. Through careful design optimization, the conversion loss of the transponder is not impacted by the measures taken to minimize its mass. The expected harmonic power versus the transmitted power is estimated based on the link analysis between the transmitter and receiver of the radar, with the link analysis itself being performed via calculation, harmonic balance simulation, and full-wave simulation. The link analysis simulation predicted a received power of -66.4 dBm for a transmitted power of +22 dBm and a range of 2.4 m. The measured received power level at the harmonic frequency, obtained from the broadside of the transponder in an anechoic test chamber, is approximately -70 dBm, which agrees well with the link analysis. Simulated and measured transponder radiation patterns are also compared and show good agreement. Low-mass transponders such as this enable tracking of smaller insects without reducing their lifespan or compromising their ability to fly at natural altitudes and ranges.

Towards Innovative Solutions for Monitoring Precipitation in Poorly Instrumented Regions: Real-Time System for Collecting Power Levels of Microwave Links of Mobile Phone Operators for Rainfall Quantification in Burkina Faso

Since the 1990s, mobile telecommunication networks have gradually become denser around the world. Nowadays, large parts of their backhaul network consist of commercial microwave links (CMLs). Since CML signals are attenuated by rainfall, the exploitation of records of this attenuation is an innovative and an inexpensive solution for precipitation monitoring purposes. Performance data from mobile operators’ networks are crucial for the implementation of this technology. Therefore, a real-time system for collecting and storing CML power levels from the mobile phone operator “Telecel Faso” in Burkina Faso has been implemented. This new acquisition system, which uses the Simple Network Management Protocol (SNMP), can simultaneously record the transmitted and received power levels from all the CMLs to which it has access, with a time resolution of one minute. Installed at “Laboratoire des Matériaux et Environnement de l’Université Joseph KI-ZERBO (Burkina Faso)”, this acquisition system is dynamic and has gradually grown from eight, in 2019, to more than 1000 radio links of Telecel Faso’s network in 2021. The system covers the capital Ouagadougou and the main cities of Burkina Faso (Bobo Dioulasso, Ouahigouya, Koudougou, and Kaya) as well as the axes connecting Ouagadougou to these cities.

Interference Mitigation for GNSS Receivers Using FFT Excision Filtering Implemented on an FPGA

GNSS receivers process signals with very low received power levels (<−160 dBW) and, therefore GNSS signals are susceptible to interference. Interference mitigation algorithms have become common in GNSS receiver designs in both professional and mass-market applications to combat both unintentional and intentional (jamming) interference. Interference excision filters using fast Fourier transforms (FFTs) have been proposed in the past as a powerful method of interference mitigation. However, the hardware implementations of this algorithm mostly limited their use to military GNSS receivers where greater power and resources were available. Novel implementation of existing FPGA technology should make interference mitigation feasible with limited hardware resources. This paper details the practicalities of implementing excision filters on currently available FPGAs trading off the achievable performance against the required hardware resources. The hardware implementation of the FFT excision mitigation algorithm is validated with the GNSS software receiver. The results indicate that the desired performance of the developed algorithm has achieved the expectations and can provide significant improvement on mitigation techniques in current GNSS receiver hardware. Two hardware implementation designs (fixed-point and float-point data type format) are developed and compared to achieve the optimal design that can provide the best performance (C/No) with the possible minimum hardware resources.

Interactive Effects of Receiver Power and Generator Status on Endorsement of Creative Ideas

Few studies have focused on how power influences an idea receiver's endorsement of creative ideas. By integrating associative evaluation theory with insights from the power literature, we identify power as an important receivers’ factor that accentuates the relation between an idea's creativity level and receivers’ endorsement. We contend that the idea generator's status is a boundary condition and, together with creativity level, the idea generator's status jointly influences the degree to which idea receivers’ power affects idea endorsement. We conducted four studies to test our hypotheses. Study 1 was a laboratory experiment. It found a two-way interaction of receiver power and creativity level, showing that compared to low-power receivers, high-power receivers expressed stronger endorsement of ideas with high levels of creativity. Study 2 was a field study in a manufacturing company. It replicated Study 1's findings and further found a three-way interaction showing that the moderating effect of receiver power was strengthened when the generator had higher rather than lower status. Studies 3 and 4 respectively replicated the two-way and three-way interactions using experiments and demonstrated positive associations as the theorized mediator, providing empirical support for the positive association account. We discuss implications of these studies and call for future research to deepen our understanding of how creative ideas are endorsed in the workplace.

Stochastic analysis of urban V2X communications: Orthogonality versus non-orthogonality

In this paper, we study the broadcasting performance of urban Vehicle-to-everything (V2X) communications at road intersections. In such environments, dense buildings obstruct the radio channel between vehicles in adjacent road segments and Non-Line-Of-Sight (NLOS) signal propagation reduces the received power level. Therefore, messages that originate from adjacent roads traveling in a non-parallel direction usually have weaker signals than those from the road segment traveling in parallel opposite direction. Besides, the high vehicular density leads to insufficient orthogonal channel resources and high level of interference. We propose to apply Non-Orthogonal Multiple Access (NOMA) to V2X communications at urban road intersections to enhance the spectrum efficiency and improve the Package Delivery Ratio (PDR) performance. With NOMA, signals from multiple transmitters are decoded together and the interference from undesired users can be canceled if these messages are retrieved. Specifically, we study two NOMA-based V2X communication schemes, namely, NOMA-V2X decoded by Successive Interference Cancellation (SIC-V2X) and NOMA-V2X decoded by Joint Decoding (JD-V2X). Based on the tools developed in stochastic geometry, we derive and compare the PDR expressions for both NOMA schemes and the Orthogonal Multiple Access (OMA) scheme. Our results indicate that 1) both NOMA schemes outperform the conventional OMA scheme and the PDR of LOS/NLOS communications with two-user access increases by 51%/369%; 2) for four-user access, the proposed NOMA scheme shows 375% goodput enhancement as compared with the OMA scheme; and 3) JD-V2X provides significant PDR enhancement compared with SIC-V2X in the high data rate regime. Finally, we also demonstrate that the random access based NOMA schemes can achieve lower transmission latency than collision-free scheduling schemes when the road is over 56% jammed.

Estimation and Mapping of the Received Power Level of Digital Signals TV Using Spatial Interpolation Methods

The signal digitization process of the open television system is still in progress, therefore, the study of the digital signal propagation has great importance so that broadcasters can develop and improve the transmission service. The field measurement of digital signal parameters is one of the most reliable means to analyze the signal propagation in a given area. In this work, received power measurements of a TV station digital signal in the city of Mossoró, Rio Grande do Norte, Brazil were performed. The objective is to implement interpolation methods and identify which is the most suitable for the spatial representation of power data in this region through the Mean Error (ME) and Root Mean Squared Error (RMSE) evaluation metrics. A good representation of the received power level contributes to the mapping of greater and lesser intensity of the digital signal in the region. The implementation of the interpolation methods was performed in Surfer® software (Golden Software, LLC), which provides the cross-validation report with the ME and RMSE values associated with each method. The Ordinary Kriging method with exponential variogram model obtained the lowest RMSE value (7.6083) and, therefore, the most adequate estimates.

Empirical measurement for path loss characteristics at multiple frequency bands from 2.2 to 14.6 GHz in chamber room

Free space path loss (FSPL) is the loss of electromagnetic signal strength. This loss is caused by the line-of-sight path through free space. Even in a line of sight (LoS) indoor single layer, as the distance increases, the path loss in the 1 GHz frequency band also exceeds the free space path loss. This is because the first Fresnel zone is shielded by the floor and ceiling. To improve the measurement results, a fully covered anechoic chamber is used in this empirical measurement. The measurement is based on multiple frequency bands from 2.23201 GHz to 14.685 GHz. This article details how to achieve it. Measurements are made to establish the correlation between the power transmit value and the frequency value. This movement involves the establishment of microwave link transmissions. Use a signal generator to control the transmit power and use a vector network analyzer in the electromagnetic compatibility (EMC) room to measure the received power level. Appropriate analysis that determines the correlation. The logarithm function developed based on the empirical experiment conducted, the result suggested the formulation of . These findings enable people to understand the required FSPL value as the power transmission and frequency change during each measurement.

Direct Modulation and Free-Space Transmissions of up to 6 Gbps Multilevel Signals With a 4.65-$\mu$m Quantum Cascade Laser at Room Temperature

A roadmap for future wireless communications is expected to exploit all transmission-suitable spectrum bands, from the microwave to the optical frequencies, to support orders of magnitude faster data transfer with much lower latency than the deployed solutions nowadays. The currently under-exploited mid-infrared (mid-IR) spectrum is an essential building block for such an envisioned all-spectra wireless communication paradigm. Free-space optical (FSO) communications in the mid-IR region have recently attracted great interest due to their intrinsic merits of low propagation loss and high tolerance of atmospheric perturbations. Future development of viable mid-IR FSO transceivers requires a semiconductor source to fulfill the high bandwidth, low energy consumption, and small footprint requirements. In this context, quantum cascade laser (QCL) appears as a promisingtechnological choice. In this work, we present an experimental demonstration of a mid-IR FSO link enabled by a 4.65-μm directly modulated (DM) QCL operating at room temperature. We achieve a transmission data rate of up to 6 Gbps over a 0.5-m link distance. This achievement is enabled by system-level characterization and optimization of transmitter and receiver power level and frequency response and assisted with advanced modulation and digital signal processing (DSP) techniques. This work pushes the QCL-based FSO technology one step closer to practical terrestrial applications, such as the fixed wireless access and the wireless mobile backhaul. Such a QCL-based solution offers a promising way towards the futuristic all-spectra wireless communication paradigm by potentially supporting the whole spectrum from the MIR to the terahertz (THz).

Two-Way Communication Digital Power Controllers for Wireless Retinal Prosthesis Systems.

Power-efficient digital controllers are proposed for wireless retinal prosthetic systems. Power management plays an important role in reducing the power consumption and avoiding malfunctions in implantable medical devices. In the case of implantable devices with only one-way communication, the received power level is uncertain because there is no feedback on the power status. Accordingly, system breakdown due to inefficient power management should be avoided to prevent harm to patients. In this study, digital power controllers were developed for achieving two-way communication. Three controllers—a forward and back telemetry control unit, a power control unit, and a preamble control unit—operated simultaneously to control the class-E amplifier input power, provided command data to stimulators, monitored the power levels of the implanted devices, and generated back telemetry data. For performance verification, we implemented a digital power control system using a field-programmable gate array and then demonstrated it by employing a wireless telemetry system.

Wireless Capsule Endoscope Localization with Phase Detection Algorithm and Adaptive Body Model.

Wireless capsule endoscopes take and send photos of the human digestive tract, which are used for medical diagnosis. The capsule’s location enables exact identification of the regions with lesions. This can be carried out by analyzing the parameters of the electromagnetic wave received from the capsule. Because the human body is a complex heterogeneous environment that impacts the propagation of wireless signals, determining the distance between the transmitter and the receiver based on the received power level is challenging. An enhanced approach of identifying the location of endoscope capsules using a wireless signal phase detection algorithm is presented in this paper. For each capsule position, this technique uses adaptive estimation of human body model permittivity. This approach was tested using computer simulations in Remcom XFdtd software using a numerical, heterogeneous human body model, as well as measurements with physical phantom. The type of transmitting antenna employed in the capsule also has a significant impact on the suggested localization method’s accuracy. As a result, the helical antenna, which is smaller than the dipole, was chosen as the signal’s source. For both the numerical and physical phantom studies, the proposed technique with adaptive body model enhances localization accuracy by roughly 30%.