Yagi Antenna Research Articles

Multiband Modified Yagi Antenna in a Shared Transverse Aperture

Multiband Modified Yagi Antenna in a Shared Transverse Aperture

A Study on a Compact Double Layer Sub-GHz Reflectarray Design Suitable for Wireless Power Transfer

The paper presents a novel small-footprint varactor diode-based reconfigurable reflectarray (RRA) design and investigates its power reflection efficiency theoretically and experimentally in a real-life indoor environment. The surface is designed to operate at 865.5 MHz and is intended for simultaneous use with other wireless power transfer (WPT) efficiency-improving techniques that have been recently reported in the literature. To the best of the authors’ knowledge, no RRA intended to improve the performance of antenna-based WPT systems operating in the sub-GHz range has been designed and studied both theoretically and experimentally so far. The proposed RRA is a two-layer structure. The top layer contains electronically tunable phase shifters for the local phase control of an incoming electromagnetic wave, while the other one is fully covered by metal to reduce the phase shifter size and RRA’s backscattering. Each phase shifter is a pair of diode-loaded 8-shaped metallic patches. Extensive numerical studies are conducted to ascertain a suitable set of RRA unit cell parameters that ensure both adequate phase agility and reflection uniformity for a given varactor parameter. The RRA design parameter finding procedure followed in this paper comprises several steps. First, the phase and amplitude responses of a virtual infinite double periodic RRA are computed using full-wave solver Ansys HFSS. Once the design parameters are found for a given set of physical constraints, the phase curve of the corresponding finite array is retrieved to estimate the side lobe level due to the finiteness of the RRA aperture. Then, a diode reactance combination is found for several different RRA reflection angles, and the corresponding RRA radiation pattern is computed. The numerical results show that the side lobe level and the deviation of the peak reflected power angles from the desired ones are more sensitive to the reflection coefficient magnitude uniformity than to the phase agility. Furthermore, it is found that for scanning angles less than 50°, satisfactory reflection efficiency can be achieved by using the classical reactance profile synthesis approach employing the generalized geometrical optics (GGO) approximation, which is in accord with the findings of other studies. Additionally, for large reflection angles, an alternative synthesis approach relying on the Floquet mode amplitude optimization is utilized to verify the maximum achievable efficiency of the proposed RRA at large angles. A prototype consisting of 36 elements is fabricated and measured to verify the proposed reflectarray design experimentally. The initial diode voltage combination is found by applying the GGO-based phase profile synthesis method to the experimentally obtained phase curve. Then, the voltage combination is optimized in real time based on power measurement. Finally, the radiation pattern of the prototype is acquired using a pair of identical 4-director printed Yagi antennas with a gain of 9.17 dBi and compared with the simulated. The calculated results are consistent with the measured ones. However, some discrepancies attributed to the adverse effects of biasing lines are observed.

Polarization reconfigurable transmitarray antenna utilizing single‐layer Huygen element for Ku‐band satellite communication

SummaryThis paper introduces a concept for designing a polarization reconfigurable transmitarray (PRT). The unit cell of the transmitarray utilizes Huygen elements, with dimensions measuring 0.6 ( corresponds to a frequency of 15 GHz). An equivalent circuit model is proposed for the unit cell based on the two‐port Z‐matrix. The proposed unit cells have a very low insertion loss of 0.5 dB at 15 GHz. The PRT is illuminated by a linearly polarized (LP) microstrip‐printed Yagi antenna. The transmitarray is designed using the proposed unit cells with a two‐level phase quantization. The collimated LP radiation emitted by the transmitarray subsequently traverses a polarization reconfigurable converter (PRC). The resultant radiation from the PRC can be either LP or circularly polarized (CP), contingent on the configuration of the PIN diodes employed within the PRC. The proposed PRT demonstrates a measured gain of 16 dBi when operating in the LP mode while achieving a peak gain of 15 dBic in the CP mode. The overall size of the proposed PRT is compact owing to a small f/d ratio (0.58). The practicality of the design is validated through fabrication and measurement. This innovative antenna design holds potential applications in the realm of Ku‐band uplink satellite communication.

Assessing the Home Range, Foraging Pattern and Roost Fidelity of Greater Short-nosed Fruit Bat (Cynopterus sphinx) in a Semi-Urban Environment

Radio telemetry is a method used in wildlife ecology to examine the movements and behaviours of animals, as well as to define their home ranges and habitat preferences. Bats, a highly diverse group of mammals, are recognized for their essential contributions to ecosystems, including seed dispersal, pollination, and pest control through their foraging activities. This study utilised radio telemetry to explore the basic foraging behaviours, range of movement, and roosting flexibility of the Cynopterus sphinx species. A total of 15 bats were equipped with compact, hand-wired, two-stage transmitter radio devices, including two harem males, nine harem females, and four non-harem males. Three groups used TRX-1000S receivers and collapsible 5-element Yagi antennas to track these radio-tagged bats. Our findings indicate that the radio-tagged female bats were the first to leave their roosts, with emergence times between 18:15 and 19:18 hrs. In contrast, harem males emerged last, following the quicker departure of non-harem males. The harem males covered an average foraging distance of 2.4 km (±0.3 km), whereas non-harem males travelled further. Both male and female bats visited multiple feeding sites nightly, with females travelling an average distance of 4.5 km (±0.9 km). Time spent at foraging sites varied among individuals. Males show higher roost fidelity than females, who frequently move between harems and roost sites. The study highlighted gender-specific differences in emergence times and distinct foraging behaviours, underlining the importance of understanding these patterns for conservation and habitat management efforts, which are crucial for supporting bats' roles as providers of ecosystem services.

Design of high‐efficiency rectenna for microwave power wireless transmission systems

Design of high‐efficiency rectenna for microwave power wireless transmission systems

Dual-band ends-fed dipole-like driver for dual-band antenna arrays

The article addresses the problem of dual-band structure designs based on the quasi-Yagi arrangements. The reported dual-band dipole antenna comprises the out-of-phase power divider, whose outputs excite the corresponding dipole arms to produce appropriate surface current distribution on them. The topology of the antenna itself is designed the way to provide high matching (the realized input reflection coefficient is not exceed minus 25 dB) at both central working frequencies. The low-band dipole is meandered to fit the substrate size. In addition, both the dipoles are excited on their remote terminals, which allows the more efficiently use of the circuit body space. The low profile implementation contributes to meeting the high demands of today and future wireless communications. The fundamental properties of linear dipole antennas, such as the Yagi, of being relatively simple in design, pure linearly polarized, having almost omnidirectional patterns made them of the great interest among researches. In addition, the Yagi arrangement itself allows building on its base even more complex antenna structures, comprised a number of linear dipoles, maintained along one of orthogonal axis. When centrally fed, the classical single-band Yagi antenna suffers from narrow band characteristics, becoming a kind of challenge, which has successfully been addressed by a number of researches in the past. At the same time, on the base of Yagi and quasi-Yagi designs it is possible to combine a number of radiating elements, producing, therefore, multi-band or wideband characteristics. This approach is highly efficient when designing multipurpose devices with different transmitting rates. In this project the novel approach for dual-band dipole antennas design is presented. The driven elements are excited from their remote terminals, forming the quasi-Yagi arrangement with untraditional excitation. The balancing scheme is formed by an out-of-phase power divider, whose outputs are connected to the dipoles arms. The topology of the antenna itself is designed to provide high matching (input reflection coefficient does not exceed minus 25 dB) at both center operating frequencies. When integrating a dual band balancing unit with the radiating elements it is crucial to provide low interference for better radiation characteristics. Besides, the surface currents on the ground plane, should not affect those on the radiating elements for better matching.

Wirelessly Pattern Reconfigurable Yagi Antenna Based on Radio Frequency Identification

This paper presents, for the first time, the implementation of a pattern reconfigurable Yagi-Uda antenna utilizing radio frequency identification (RFID) technology for remote pattern control. The proposed scheme emphasizes the use of wireless communication instead of long metal cables, resulting in improved stability of the antenna’s pattern and return loss. Two low-power consumption single-pole-double-throw (SPDT) switches are employed on a passive resonator, enabling it to function as a director or reflector under the long-range control (up to 25 m) of an RFID reader. Measurement results demonstrate a −10 dB impedance bandwidth of 4.2% and a gain of 7 dBi at 2.41 GHz. The entire system operates with an ultra-low power consumption of 12 μW.

Fully Integrated 24-GHz 1TX-2RX Transceiver for Compact FMCW Radar Applications.

A fully integrated 24-GHz radar transceiver with one transmitter (TX) and two receivers (RXs) for compact frequency modulated continuous wave (FMCW) radar applications is here presented. The FMCW synthesizer was realized using a fractional-N phase-locked loop (PLL) and programmable chirp generator, which are completely integrated in the proposed transceiver. The measured output phase noise of the synthesizer is -80 dBc/Hz at 100 kHz offset. The TX consists of a three-bit bridged t-type attenuator for gain control, a two-stage drive amplifier (DA) and a one-stage power amplifier (PA). The TX chain provides an output power of 13 dBm while achieving <0.5 dB output power variation within the range of 24 to 24.25 GHz. The RX with a direct conversion I-Q structure is composed of a two-stage low noise amplifier (LNA), I-Q generator, mixer, transimpedance amplifier (TIA), a two-stage biquad band pass filter (BPF), and a differential-to-single (DTS) amplifier. The TIA and the BPF employ a DC offset cancellation (DCOC) circuit to suppress the strong reflection signal and TX-RX leakage. The RX chain exhibits an overall gain of 100 dB. The proposed radar transceiver is fabricated using a 65 nm CMOS technology. The transceiver consumes 220 mW from a 1 V supply voltage and has 4.84 mm2 die size including all pads. The prototype FMCW radar is realized with the proposed transceiver and Yagi antenna to verify the radar functionality, such as the distance and angle of targets.

Machine Learning-Based Approach for bandwidth and frequency Prediction for N77 band 5G Antenna

Yagi antennas are useful for wireless communications because of the directional gain they provide, allowing the antenna to concentrate the signal in either the transmission or reception direction. It is built on a substrate made of FR-4, this antenna has a return loss of −46.85 dB at 3.6 GHz and a bandwidth of 3.3–4.2 GHz within a −10 dB range, making it ideal for use in the n77 bands. Not only is it small, with a size of 0.642λ 0 × 0.583λ 0, but it also has a maximum gain of 7.95 dB and a maximum directivity of 8.58 dB. This study investigates several approaches to estimating the performance of an antenna. These approaches include simulation with a variety of software tools, including as CST, HFSS, and Altair Feko; curve fitting technology; and the RLC equivalent circuit model. After that, simulation with CST MWS is used to collect a large amount of data samples, and then supervised regression machine learning (ML) methods are used to determine the resonance frequency and bandwidth of the antenna. When it comes to predicting bandwidth and frequency, Random Forest Regression demonstrates an exceptional level of performance, particularly when comparing with the results produced by curve-fitting tools, neural networks, and regression machine learning models. When all of these considerations are taken into account, it is clear that the antenna is an outstanding option for the n77 band of a 5G communication system.

Analysis of electromagnetic wave ignition mechanism and calculation of power threshold in underground coal mine

This study critically assesses the potential risks associated with the implementation of 5G radio frequency signals in coal mines. The empirical findings underscore that, under uniform excitation conditions, when situating a PCB loop antenna at the focal points of maximum near-field and far-field emissions from a Yagi antenna, both simulations and analytical computations converge on a safe power threshold of 450W for the transmitting antenna in the near field. This limit augments to 7200W in the far field context. In a hypothetical scenario devoid of transmission losses, the safe power threshold for the transmitter is projected to be 100W. It is imperative to acknowledge that the safety threshold for the RF source is intricately linked to the internal resistance of the receiving antenna. As a corollary, the probability of an inadvertent high-gain conductive spark discharge is substantially minimized, intimating that real-world safe thresholds might be greater than the values proposed herein.

Dual-Polarization Yagi Antenna for Meter Wavelength Range

Dual-Polarization Yagi Antenna for Meter Wavelength Range

Highly-efficient tunable dipole-driven Yagi–Uda antenna with end-fire radiation for terahertz application

This paper presents a highly efficient tunable dipole antenna with omnidirectional radiation. The main radiator of the hybrid dipole is designed using a perfect electric conductor, whereas tunability has been achieved using graphene strips in the antenna’s proximity. The dipole antenna resonates at 1.3785 THz and provides a bandwidth (BW) of 8.58% for the graphene’s chemical potential (μc) equal to 0.6 eV. The peak gain and total efficiency (ηTotal) are 1.46 dBi and 83.13%, respectively. The proposed dipole provides tunability from 1.32 to 1.411 THz by varying μc from 0.4 to 0.7 eV. Further, a compact dipole-driven tunable Yagi–Uda antenna has been designed with end-fire radiation. The proposed Yagi–Uda antenna has a size of only 90 μm × 60 μm, i.e., 0.61λg×0.38λg, where λg is the guided wavelength calculated at 1.3631 THz and provides tunability from 1.328 to 1.5 THz. The peak gain, front-to-back ratio (FBR) and ηTotal at 1.3631 THz for the μc = 0.6 eV are found to be 4.93 dBi, 17.3 dB, and 63.36%, respectively. A practical parallel plate DC biasing configuration with a common ground plane has also been proposed to independently tune the μc of each element in the passive Yagi–Uda array. The proposed Yagi antenna provides reasonable gain and FBR to cater for high propagation loss in the terahertz regime.

Machine learning-based technique for resonance and directivity prediction of UMTS LTE band quasi Yagi antenna

In this study, we have presented our findings on the deployment of a machine learning (ML) technique to enhance the performance of LTE applications employing quasi-Yagi-Uda antennas at 2100 MHz UMTS band. A number of techniques, including simulation, measurement, and a model of an RLC-equivalent circuit, are discussed in this article as ways to assess an antenna's suitability for the intended applications. The CST simulation gives the suggested antenna a reflection coefficient of -38.40 dB at 2.1 GHz and a bandwidth of 357 MHz (1.95 GHz-2.31 GHz) at a -10 dB level. With a dimension of 0.535λ0×0.714λ0, it is not only compact but also features a maximum gain of 6.9 dB, a maximum directivity of 7.67, VSWR of 1.001 at center frequency and a maximum efficiency of 89.9%. The antenna is made of a low-cost substrate, FR4. The RLC circuit, sometimes referred to as the lumped element model, exhibits characteristics that are sufficiently similar to those of the proposed Yagi antenna. We use yet another supervised regression machine learning (ML) technique to create an exact forecast of the antenna's frequency and directivity. The performance of machine learning (ML) models can be evaluated using a variety of metrics, including the variance score, R square, mean square error (MSE), mean absolute error (MAE), root mean square error (RMSE), and mean squared logarithmic error (MSLE). Out of the seven ML models, the linear regression (LR) model has the lowest error and maximum accuracy when predicting directivity, whereas the ridge regression (RR) model performs the best when predicting frequency. The proposed antenna is a strong candidate for the intended UMTS LTE applications, as shown by the modeling results from CST and ADS, as well as the measured and forecasted outcomes from machine learning techniques.

ANALYSIS OF FM BROADCAST RADIO SIGNAL RECEPTION IN BORDER AREAS USING SEVERAL ANTENNA MODELS

Information is now a basic need for every people, including the people in border areas. Therefore, it is an obligation for the government to provide information media that can be reached by all levels of society, one of which is FM radio broadcast media. This research aims to identify and assess the quality of FM radio broadcasts in the border area of Sambas Regency using several antenna models which in the area is a vulnerable area of signal leakage by neighbouring countries and far from Indonesian broadcast transmitters. The assessment of FM radio broadcast quality is carried out with the determination of SINPO (Signal, Interference, Noise, Propagation, Overall) values and field strength meter measurements. The data obtained were analysed using the Miles and Hubberman interactive data processing technique. From the research conducted, it was found that 10 Malaysian FM radio broadcast channels and 2 broadcast channels from Indonesia where the dominant broadcast was received better by the yagi antenna. There were also broadcasts whose frequencies fell out of compliance with the regulations.

Design and construct a Yagi Antenna with Three Reflector Element to Strengthen 4G Signal in Rural Areas

Rural areas are indicated to be still difficult to reach by 4G signals due to diverse topographical conditions and uneven landscapes, especially hilly areas that weaken the signal reception level in this region. To make the 4G signal accessible in this area, a repeater in the form of an antenna is needed to strengthen the signal. In this study, a yagi antenna is designed with three reflector elements at a working frequency of 1800 Mhz 4G LTE, expected to produce a minimum gain of 12 dBi and a more focused antenna radiation to strengthen the 4G signal in rural areas. The antenna design was simulated using CST Studio Suite software, with optimized simulation results yielding a return loss of -22 dB, VSWR 1.167, and gain 12.40 dBi. From the measurements obtained, the yagi antenna with three reflector elements works well at a frequency of 1800 Mhz, with a return loss of -34.77 dB, VSWR 1.065, gain 12.96 dBi, and unidirectional radiation. With the optimal antenna parameters and the addition of three reflector elements, it's possible to increase the gain value, even though the gain increase isn't substantial, and it narrows the HPBW (Half Power BeamWidth) value. Moreover, testing the yagi antenna at 3 different distances demonstrated that the resulting gain value can enhance 4G signal speed in rural areas

Machine learning-based technique for gain and resonance prediction of mid band 5G Yagi antenna

In this study, we present our findings from investigating the use of a machine learning (ML) technique to improve the performance of Quasi-Yagi–Uda antennas operating in the n78 band for 5G applications. This research study investigates several techniques, such as simulation, measurement, and an RLC equivalent circuit model, to evaluate the performance of an antenna. In this investigation, the CST modelling tools are used to develop a high-gain, low-return-loss Yagi–Uda antenna for the 5G communication system. When considering the antenna’s operating frequency, its dimensions are {0.642}lambda _0times {0.583}lambda _0. The antenna has an operating frequency of 3.5 GHz, a return loss of -43.45 dB, a bandwidth of 520 MHz, a maximum gain of 6.57 dB, and an efficiency of almost 97%. The impedance analysis tools in CST Studio’s simulation and circuit design tools in Agilent ADS software are used to derive the antenna’s equivalent circuit (RLC). We use supervised regression ML method to create an accurate prediction of the frequency and gain of the antenna. Machine learning models can be evaluated using a variety of measures, including variance score, R square, mean square error, mean absolute error, root mean square error, and mean squared logarithmic error. Among the nine ML models, the prediction result of Linear Regression is superior to other ML models for resonant frequency prediction, and Gaussian Process Regression shows an extraordinary performance for gain prediction. R-square and var score represents the accuracy of the prediction, which is close to 99% for both frequency and gain prediction. Considering these factors, the antenna can be deemed an excellent choice for the n78 band of a 5G communication system.

Microwave transmission method for the detection of water holdup in oil-water mixtures based on a Yagi antenna

In this paper, Yagi antennas are introduced into microwave transmission measuring instruments as the transmit and receive antennas for detecting moisture content in oil-water mixtures. A Yagi antenna is designed, where the simulation results show a peak gain of 9 dBi and the reflection coefficient S11 is lower than ???10 dB in a frequency band of 2.25-4 GHz. Meanwhile, the measurement result using a vector network analyser shows that the Yagi antenna works in the frequency band of 2.9-4.15 GHz, indicating that measurement results shifted to high frequencies. Based on the Yagi antennas, a moisture content measuring system using the microwave transmission method is designed and constructed, where the measurement results show the Yagi directional high-gain microwave antenna used in this paper can achieve water holdup measurement in the range of 0-100%, where the relative error is less than ??15% and the absolute error is within ??2.341%.

Design and Analysis of Sphere Yagi antenna at 915 MHz Band for LoRaWAN Application

Using a frequency of 915 MHz as an operating point, this project has analyzed and refined the design of a Sphere Yagi antenna. In CST, we have begun the research phase and created a preliminary design for an antenna. The simulation results have been analyzed, and then fabrication, testing, and measurement have been carried out. To begin the manufacturing process, a single-sided copper board is cut into sphere shapes, with the length of each plate varying depending on the size of the sphere. Drilling machines are then used to create a hole in each of the plates. As a result, everything is coming together nicely. In addition, both indoor and outdoor settings have been used for testing and experiments. Therefore, the antenna design works well in 915 MHz frequency, but the signal weakens when it travels more than 100 meters away. An improved antenna transmitter’s power output can fix this. This project can be extended to cover the 2.4 GHz and 5 GHz frequencies. So, the antenna layout can be employed to improve the wireless connection of communication devices that need extensive range.

High-Gain and Wideband Circularly Polarized Endfire Leaky-Wave Antenna Array Based on the Complementary Dipole

A circularly polarized (CP) endfire leaky-wave antenna (LWA) array with the merits of high-gain and broad operation band is proposed in this communication. This array configuration is composed of double-row antenna cells arranged linearly, which derives from the performance of the complementary dipole (loop and electric dipole). By introducing the coupling loop and the electric dipole along both side of a metallic parallel strip line (PSL), the effective radiation is generated from this structure due to the periodic perturbation. Based on the intrinsic 90° phase differences of the complementary dipole, CP performance is easily achieved by turning the antenna unit size reasonably. Similar to the yagi antenna, this linearly antenna array achieves an endfire radiation. A fabricated prototype has verified the design concept, which shows that the proposed antenna has a relative impedance bandwidth of 51.1%, 3dB axial ratio (AR) bandwidth of 25%, and the gain of 1.1-13.59dBi within the operation band.

Using recovered radio transmitters to estimate positioning error and a generalized Monte Carlo simulation to incorporate error into animal telemetry analysis

BackgroundMobile radio tracking is an important tool in fisheries research and management. Yet, the accuracy of location estimates can be highly variable across studies and within a given dataset. While some methods are available to deal with error, they generally assume a static value for error across all detections. We provide a novel method for making detection-specific error estimates using detections of recovered transmitters (i.e., mortalities or tag expulsion). These data are used to establish the relationship between received signal strength (RSS) and positional error, which can then be used to predict positional error of detections for fish at large. We then show how detection-specific estimates can be integrated into a Monte Carlo framework to analyze movement in ways robust to spatial uncertainty.ResultsIn a telemetry study in a large river (~ 90 m), we recovered 22 transmitters to estimate and model positional error. Error averaged 94 m (range = 1–727 m) for transmitters tracked by researchers on foot using a Yagi antenna, and 200 m (range = 1–1141 m) for transmitters tracked from vehicles using an omnidirectional whip antenna. Transmitters located near roads were tracked more accurately with both methods. Received signal strength was a strong predictor of positional error (r2 = 0.86, ground tracking; 0.65, tracking from truck) and was thus used to make detection-specific estimates of error for detections of fish at large. Monte Carlo analysis for a binary movement classification revealed that only 18% of location estimates could be confidently assigned to movement (p < 0.05); the remainder were associated with stasis or movement that was within the range of positional error. Ignoring positional error led to positive bias of up to 1300% in individual movement estimates and varied seasonally—it was highest when fish were inactive and lowest when fish were most active.ConclusionUsing recovered transmitters and RSS models to estimate telemetry error is a viable alternative to staged ‘dummy transmitter’ trials and assuming error is a constant. Our proposed approaches to incorporate detection-specific error estimates into analysis are broadly applicable and can ‘make the most’ out of highly accurate detections while also cautiously extracting spatial information from less-accurate detections.