Antenna Setup Research Articles

Performance of an Anti-Phase Technology-Powered Microwave Ablation System on Ex Vivo Liver, Lung and Kidney: Analysis of Temperature Trend, Ablation Size and Sphericity

PurposeInvestigating the performance of the new Dophi™ M150E Microwave Ablation System, in terms of temperature distribution, ablation size and shape, reproducibility.Materials and MethodsThe Dophi™ M150E Microwave Ablation System was tested on ex vivo liver, lung and kidney, at 6 different settings of time, power and number of MW antennas (single antenna: 50 and 100 W at 5 and 10 min; double antenna: 75 W at 5 and 10 min). The temperature distribution was recorded by Fiber Bragg Grating sensors, placed at different distances from the antennas. The ablation axes were measured and the sphericity index was calculated.ResultsThe standard deviation of ablation axes was < 5 mm, except at the highest energy and time setting for the lung. A maximum temperature rise of ~ 80 °C was measured. The measured ablation axes are overall comparable with the manufacture’s values, especially at lower power and with one MW antenna (average maximum difference is 7 mm). The mean sphericity index of 0.95, 0.79 and 0.9 was obtained for the liver, lung and kidney, respectively, with a single antenna. With double antenna setup, the sphericity index was closer to 1 when 75 W for 10 min were used.ConclusionsDophi™ M150E allows good reproducibility of ablation axes for all cases except in the lung at the highest energy level. With one antenna, an almost spherical ablation area for the liver and kidney was obtained. Using double antenna results in more homogeneous temperature distribution within the tissue compared to single antenna.Graphical

Design and performance analysis of L‐slotted MIMO antenna with improved isolation using defected ground structure for S‐band satellite application

SummaryThe increasing prevalence of MIMO technology in wireless communication networks is attributed to its ability to augment system capacity and dependability. Consequently, there is a notable enthusiasm for the advancement and implementation of S‐band applications. Nevertheless, the mutual coupling between numerous antennas presents a crucial obstacle to MIMO system performance. This paper presents a novel technique that utilizes a defective ground structure with parasitic components to increase antenna isolation and gain. Additionally, an L‐shaped slot is incorporated into the patch element to enhance the antennas impedance bandwidth. Antennas are intentionally placed in a perpendicular arrangement to minimize the impact of the coupling effects. The antenna exhibits an impedance bandwidth in the frequency range of 2.62–2.79 GHz. Furthermore, the utilization of a four‐element MIMO antenna setup with a defective ground structure yields outstanding isolation properties, with values notably lower than −25 dB. To achieve an optimal MIMO performance, we assessed various diversity parameters, including diversity gain, channel capacity loss, total active reflection coefficient, and envelope correlation coefficient. The parameter values were within acceptable limits (ECC &lt; 0.04, DG = 10 dB, TARC &lt; 0 dB, and CCL &lt; 0.1 bits/s/Hz). This research paper therefore offers essential insights into the design and optimization of MIMO antennas specifically for 2.7 GHz applications.

First Results from a Broadband Search for Dark Photon Dark Matter in the 44 to 52 μeV Range with a Coaxial Dish Antenna.

We present first results from a dark photon dark matter search in the mass range from 44 to 52 μeV (10.7-12.5GHz) using a room-temperature dish antenna setup called GigaBREAD. Dark photon dark matter converts to ordinary photons on a cylindrical metallic emission surface with area 0.5 m^{2} and is focused by a novel parabolic reflector onto a horn antenna. Signals are read out with a low-noise receiver system. A first data taking run with 24days of data does not show evidence for dark photon dark matter in this mass range, excluding dark photon photon mixing parameters χ≳10^{-12} in this range at 90% confidence level. This surpasses existing constraints by about 2 orders of magnitude and is the most stringent bound on dark photons in this range below 49 μeV.

Propagacija milimetarskih talasa na osnovu NYUSIM modela kanala uzimajući u obzir kišu u tropskim oblastima

The impact of atmospheric attenuation on wireless communication links is much more severe and complicated in tropical regions. That is due to the extreme temperatures, intense humidity, foliage and higher precipitation rain rates. This paper investigates the propagation of mm waves at 38 GHz. Key propagation channel parameters such as the path loss, path loss exponent, Rician K-factor, root mean square, delay spread and received power have been investigated considering the rain attenuation. The NYUSIM simulator was used. The analysis results have been classified considering rain attenuation, antenna setup, link distances, antenna height and antenna gain.

DESIGN AND IMPLEMENTATION OF MULTIPLE-IN, MULTIPLE-OUT ANTENNA FOR S-BAND SATELLITE APPLICATIONS

The popularity of multiple-in, multiple-out (MIMO) technology in wireless communication systems has increased due to its ability to enhance system capacity, coverage, and reliability, leading to a rising interest in designing and implementing MIMO antennas for various frequency bands, such as the S-band. However, mutual coupling between multiple antennas can pose a significant challenge in the performance analysis of MIMO systems. In this study, we introduce a novel approach involving the utilization of an L-shaped slot in a patch element placed on an economical FR4 epoxy material with a relative permittivity of 4.4 and a loss tangent of 0.02. Multiple antennas are strategically positioned in an orthogonal arrangement to minimize coupling effects. Our proposed antenna design successfully achieves an impedance bandwidth that aligns with the -10 dB reference over a frequency range from 2.78 GHz to 2.66 GHz, making it suitable for S-band satellite applications. Furthermore, by employing a four-element MIMO antenna setup, we achieve excellent isolation characteristics, with values below -20 dB. To ensure excellent MIMO performance, we consider some diversity parameters such as envelope correlation coefficient (ECC) and diversity gain (DG), which we investigate and find to be within standard limits (ECC &amp;#60; 0.04, DG &amp;#61; 10 dB). Our study offers valuable insights into designing and optimizing MIMO antennas for S-band satellite applications and can serve as a useful reference for future research in this area.

Breast Cancer Detection by Terahertz UWB Microstrip Patch Antenna Loaded with 6X6 SRR Array

This paper presents cancer tumor detection in the breast phantom and cancer tissue detection in the excised breast tissue phantom by the ultra-wideband terahertz microstrip patch antenna. The proposed antenna structure consists of a silicon dioxide substrate with a dielectric constant of 3.9 and a thickness of 200 µm, a radiating gold patch of length 560 µm, width 700 µm, and thickness 36 µm which is on top of the substrate, and an array of 6 × 6 gold Split Ring Resonator at the ground plane. Each SRR is separated by 28.75 µm. An array of SRR at the antenna's ground plane enhances bandwidth, efficiency, gain, directivity and reduces back radiation. The antenna operates in the frequency range of 0.1-3 THz, with a gain of 19.22 dBi and an efficiency of 98.74%. The antenna setup with the breast phantom and excised breast tissue phantom in between have been designed and analyzed in the CST microwave studio 2019 version. Tumor in the breast phantom and the cancerous tissue in the breast tissue phantom can be detected by placing the phantoms between the two identical antennas. The difference in the dielectrics of the breast and the tumor layers can determine the difference between healthy and malignant tissue. A typical breast phantom model that replicates a real-human breast and a specific excised tissue that replicates the actual breast tissue with and without cancer tissue in terms of dielectric and optical properties has been employed in this study to detect the tumor and cancerous tissue.

Full 360° beam steering millimetre‐wave leaky‐wave antennas coupled with bespoke 3D‐printed dielectric lenses for 5G base stations

AbstractA fast beam‐steering capability has been demonstrated using an array of high‐gain corrugated substrate integrated waveguide (CSIW) slot antennas coupled with a bespoke dielectric lens. The proposed system prototype has been simulated, fabricated, and measured. The proposed system is shown to have a full 360° beam‐steer in azimuth plane with an angular sensitivity of 9°, half power beamwidth (HPBW) of 18° and a gain of &lt; 20.5 dBi at n257 frequency band of 26 to 29 GHz. Further, the antenna is shown to have a fixed frequency beam steer of ±15° along with a frequency‐controlled beam‐scanning of ±45° in the elevation plane. The antenna setup is shown to be suitable for applications for 5G base‐stations.

Antenna Setup for Future Joint Radar-Communications – Characteristics and Mounting Positions

Abstract. The development of millimeter wave systems is driven by the strong trend toward new communications generations and especially by the emerging joint radar and communications design approach. Safety-critical applications like platooning or intersection assistance will significantly benefit from the combination of sensing and communications. While radar performs a channel measurement and thus, needs a wide field of view (especially in city/intersection scenarios), communications aims to minimize the interference for other not addressed receivers (e. g. in a platoon) by a focused antenna design. The proposed work extends the analysis of the influence of various antenna positioning for a typical automotive scene by taking also different characteristics (antenna gain, half power beamwidth, and sidelobe level) into account. Hereby, it is mandatory to investigate the communications and sensing performance simultaneously. The positions at the front bumper – typical for radar sensors – and especially at the left mirror convinced regarding the vehicular communications as well as the sensing behaviour. Applying focused antennas is promising, however, has also limits if the signals are not received out of the main beam but out of the sidelobes, resulting in a critical communications performance. Thus, beam steering is recommended to be applied in the future.

Heart ID: Biometric Identification Using Wearable MIMO RF Heart Sensors

Biometric identification (ID) has become increasingly prevalent in the digital era. Static biometric methods, such as fingerprint and facial recognition are widely accepted, yet generally vulnerable to targeted presentation attacks. Current development has expanded to dynamic biometrics, such as gait and electrocardiogram, that enable continuous authentication and are significantly more resistant to presentation attacks. However, dynamic biometrics often involve cumbersome acquisition which restricts their widespread use. Here, we introduce Heart ID, a novel dynamic biometric system that uses near-field coherent sensing (NCS) with a multiple-in multiple-out (MIMO) radio-frequency (RF) antenna setup to non-invasively acquire detailed recordings of internal cardiac dielectric boundary motion over clothing. NCS couples localized energy to the heart to derive interpersonal structural differences, while MIMO significantly increases the biometric entropy compared to single-point observation. We performed a human study of 20 subjects as well as 2 longitudinal evaluations, and employed an unsupervised feature extraction method to explore the ID performance of this new biometric. We found an ensemble classification approach using features derived from unsupervised learning can achieve accuracy exceeding 99% at a 40-second epoch.

Microwave Imaging With Novel Time-Domain Clutter Removal Algorithm Using High Gain Antennas for Concealed Object Detections

This paper presents a novel time-domain clutter removal algorithm for microwave imaging of concealed objects using a new high gain ultra-wideband (UWB) antipodal antenna. Bistatic antenna setup is employed to image the objects like a gun prototype, knife and blade using UWB Gaussian modulated pulses. A synthetic aperture radar (SAR) beamforming algorithm with a new clutter removal method is adopted for microwave imaging of the objects inside and outside the anechoic chamber. The proposed algorithm successfully removes the unwanted clutter from the measured scanning data, with only single scanning of the target area. The proposed method along with windowing, envelope detection and finally image reconstruction results in effective reconstruction of the concealed target as compared to the existing methods in the literature. An UWB high gain antipodal antenna is designed for the proposed imaging setup with a peak gain of 26 dBi at 8.4 GHz, which is the highest among previously reported UWB antennas. The proposed antenna achieves a wide gain bandwidth over 6 – 14 GHz (80%) with a gain of > 18 dBi. Simulation and measured results validate the design principle of the antenna with characteristics like high front to back ratio, narrow half-power beam width, and low cross-polarization. In the opinion of the authors, the proposed clutter removal algorithm is the simplest and effective method for single-time scanning of the concealed targets, in a realistic scenario.

Impact of dielectric substrates on chipless RFID tag performance

AbstractA five-slot hexagonal shape chipless RFID tag is designed, simulated, and manufactured on FR4 substrate. The designed tag's copper geometry was replicated on a wide range of dielectric substrate to quantify the impact on resonance quality factor (RQF) and resonating frequencies. The tag's performance was assessed in three configurations. First, a hexagonal shape tag's radar cross section (RCS) was studied over different dielectric substrates. The various dielectric substrate effects were investigated over the maximum read range, resonant frequencies and RQF. In the second evaluation, the physical geometry of the tag was adjusted to achieve the spectral signatures in 2–7 GHz frequency band with high RQF. In step three, the optimized tag geometry was manufactured on FR4, Roger Duroid 5880, and polyethylene naphthalate (PEN) substrates. Denford milling machine for PCB engraving and inkjet printing for silver nanoparticles deposition were used for tags manufacturing. During tag manufacturing, copper and silver were used as conducting materials for RCS backscattering. The tag RCS response was measured by vector network analyzer with bi-static antenna setup. The analysis of different dielectric substrate provides a pathway of designing a novel substrate by using various nanomaterials.

Broadband 400 GHz On-Chip Antenna With a Metastructured Ground Plane and Dielectric Resonator

The analysis, modeling, design, simulation, and experimental evaluation of a 400 GHz on-chip antenna is presented, with a novel combination of metastructures, a microstrip patch, a quartz-based dielectric resonator, and a diamond-based antireflex layer—all integrated on a 35 nm InGaAs metamorphic high-electron-mobility transistor (mHEMT) technology. The said combination represents a first-time implementation for all submillimeter-wave-capable semiconductor technologies. Circumventing a substrate-thickness limitation of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.98 \mu \text{m}$ </tex-math></inline-formula> , a state-of-the-art broadband, efficient, and to-the-broadside radiating on-chip antenna solution is realized. It achieves a measured impedance bandwidth of 100 GHz, 25.6%, spanning from 340 to 440 GHz. A consistent pattern bandwidth of 75 GHz is recorded, with an efficiency of 50%–66% and a directivity of up to 10.4 dBi—or 27 dBi, with the utilization of a polypropylene-based dielectric lens. The theoretical analysis of the proposed on-chip antenna is presented, and two modeling approaches are shown and compared. Between the analytical and the 3-D electromagnetic (EM) model, the latter is chosen as it offers greater precision in defining the metastructure unit cell and enables the inclusion of the remaining components of the proposed antenna setup. The measured reflection coefficient and far-field patterns are compared to simulations via the utilized model, and a strong agreement is observed. These far-field patterns are acquired with the on-chip antenna inserted within a broadband 400 GHz transmitter submillimeter-wave monolithic integrated circuit, processed on the 35 nm mHEMT technology.

New Antenna Selection Schemes for Full-Duplex Cooperative MIMO-NOMA Systems

In this paper, we address the antenna selection (AS) problem in full-duplex (FD) cooperative non-orthogonal multiple access (NOMA) systems, where a multi-antenna FD relay bridges the connection between the multi-antenna base station and NOMA far user. Specifically, two AS schemes, namely max-U1 and max-U2, are proposed to maximize the end-to-end signal-to-interference-plus-noise ratio at either or both near and far users, respectively. Moreover, a two-stage AS scheme, namely quality-of-service (QoS) provisioning scheme, is designed to realize a specific rate at the far user while improving the near user’s rate. To enhance the performance of the QoS provisioning AS scheme, the idea of dynamic antenna clustering is applied at the relay to adaptively partition the relay’s antennas into transmit and receive subsets. The proposed AS schemes’ exact outage probability and achievable rate expressions are derived. To provide more insight, closed-form asymptotic outage probability expressions for the max-U1 and max-U2 AS schemes are obtained. Our results show that while the QoS provisioning AS scheme can deliver a near-optimal performance for static antenna setup at the relay, it provides up to 12% average sum rate gain over the optimum AS selection with fixed antenna setup.

Sectorized FMCW MIMO Radar by Modular Design With Non-Uniform Sparse Arrays

Automotive radars are designed to enhance road user safety and reduce the number of accidents on public roads and there is a constant demand to improve the performance for these radars. In this paper, a novel proof-of-concept multiple-input multiple-output (MIMO) radar architecture is presented by frequency modulated continuous waveform (FMCW) transmission. For enhanced angular resolution, the radar uses a two-tier antenna setup leading to a sparse array arrangement, mainly in an effort to mitigate grating lobes and to offer different illuminations of the same scenario. Also, the experimentally verified sparse radar antenna designed for target detection at the receiver, achieves modest sidelobe levels and grating lobes well below 12 dB from the main beam maximum, whilst still maintaining competitive half-power beamwidths when compared to more conventionally spaced arrays. Moreover, the high impedance bandwidth of this receiver array and the supporting radar electronics (more than 6%) allows for the detection of targets at only a 10 cm spatial separation. The complete system is also capable of seeing a wide field-of-view (FOV) since it utilizes a network of radar modules to cover the forward −90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> to +90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> angular range by sectorization. In the best case, the measured radar system can resolve targets that are a distance of just <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 2^\circ$</tex-math></inline-formula> apart in angular separation.

Variation of receiver code biases under the influence of the receiver type and antenna configuration in the IGS network

Receiver code biases (RCBs) are known to be time delays within the receiver caused by their hardware imperfections. To better understand the characteristics of RCBs, the un-combined (UC) and ionosphere-free (IF) precise point positioning functional models are adapted and re-parameterized to estimate the variation of RCBs as a time-variant parameter. In this study, we analytically studied the temporal variations of RCBs; although there exists a benchmark difference between the UC and IF models, their estimates are in accordance with each other. Additionally, this contribution assesses the inter-day stability of RCBs with weekly observations from 165 globally distributed international global navigation satellite system service stations equipped the receivers of three mainly types. The inter-day stability results of RCB revealed that the RCBs of POL2 and OUS2 have better stability over consecutive 7 d and the single differenced (SD) RCBs can reach 0.2 m in the best case. The results show that 74.83% of the stations are equipped with Trimble receivers under the condition that the mean SD RCB values are between −0.5 and 0.5 m, while 85.57% of the stations are equipped with Septentrio receivers and the stations equipped with Javad can reach 84.35% under this condition. The RCB estimates are also relatively stable for the case in which the receiver hardware device stays unchanged. The relationship between RCBs, receiver type, and antenna configuration is found using six groups of receivers. A strong correlation exists between RCBs, receiver type, and antenna configuration, which is more obvious among Septentrio receivers. The results show that the Pearson correlation coefficients were all higher than 0.9, and the standard deviation of between-receiver RCBs was smaller than 0.327 m when equipped with Septentrio receivers. We concluded that there is a strong relationship between the receiver-related pseudorange biases and the receiver and antenna setup.

Tri-Band Bidirectional Antenna for 2.4/5 GHz WLAN and Ku-Band Applications

A compact tri-band, low profile, and lightweight antenna is proposed for 2.4/5 GHz WLAN and Ku-band applications. The antenna geometry was a radiating rectangular patch surrounded by a wide circular slot with an inverted-L strip connected to one side of the slot. It was mounted on a copper layer of a single side FR4 substrate with a dielectric constant of 4.3 and a height of 1.6 mm. It was fed by a 50-Ω coplanar waveguide. This design was very compact (40 × 40 × 1.6 mm3). Simulated and actual measurements of an antenna setup in the laboratory verified that the antenna’s bidirectional radiation pattern completely covered the three transmission bands: 2.4–2.485 GHz, 5.15–5.825 GHz and 13.4–17.7 GHz with less than 10-dB return loss and maximum gains of 2.35 dBi, 4.41 dBi and 4.71 dBi, respectively. Wireless communication for the self-navigated vehicle, for one example, is fully supported by this single antenna.

Prototype for pulsar observations at low radio frequencies using log-periodic dipole antennas

A prototype for dedicated observations of pulsars and other astrophysical transients in the frequency range 50\,-\,80\,MHz has been recently commissioned at the Gauribidanur radio observatory near Bangalore in India. The antenna set-up, analog \& digital receiver systems, and the initial observations are presented.

Millimetre-Wave Propagation Channel Based on NYUSIM Channel Model With Consideration of Rain Fade in Tropical Climates

The impact of atmospheric attenuation on wireless communication links is much more severe and complicated in tropical regions. That is due to the extreme temperatures, intense humidity, foliage and higher precipitation rain rates with large raindrop sizes. This paper investigates the propagation of the mm-waves at the 38 GHz link based on real measurement data collected from outdoor microcellular systems in Malaysia. The rainfall rate and received signal level have been measured simultaneously in 1-minute time intervals for one year over a 300 m path length. The rain attenuation distributions at different percentages of exceedance time have been compared with the modified distance factor of the ITU-R P.530-17 model. The average link availability calculated with the measured rain rates has been analysed. Additionally, the key propagation channel parameters such as the path loss, path loss exponent, Rician K-factor, root mean square, delay spread and received power have been investigated considering the rain attenuation. These propagation channel parameters have been analysed using MATLAB software and explained with the help of the latest NYUSIM channel model software package (Version 2.0). The analysis results have been classified considering rain attenuation, antenna setup, link distances, antenna height and antenna gain. The outcomes revealed that the rain fade predicted by applying the modified distance factor provides high consistency with the measured fade in Malaysia and several available measurements from different locations. The large-scale path loss model in the NYUSIM simulation result was around 126.23 dB by considering the rain attenuation effects on the 300m path length. This work shows that the NYUSIM channel model offers more accurate rendering results of path loss for omnidirectional and directional antenna transmissions without rain fade. This study proves that the ability to provide good coverage and ultra-reliable communication for outdoor and outdoor-to-indoor applications during rain in tropical regions must be sufficiently addressed.

Concealed Object Detection With Microwave Imaging Using Vivaldi Antennas Utilizing Novel Time-Domain Beamforming Algorithm

A time-domain novel beamforming algorithm for ultra-wideband (UWB) microwave imaging is furnished in this paper. A monostatic and bistatic antenna setup is utilized to transmit and receive custom UWB pulses. This setup is employed to image various metallic and non–metallic threats attached to a human body. The imaging results demonstrate that the proposed beamforming algorithm allows effective reconstruction of different targets for both monostatic and bistatic cases. An ultra-wideband high gain Antipodal Vivaldi Antenna (AVA) is used as the transducer for the proposed imaging setup. The designed transducer demonstrates measured impedance bandwidth from 660 MHz to 15 GHz (182%) with a peak gain of 15 dBi at 8 GHz. The quality and accuracy of the proposed beamforming algorithm is tested outside the anechoic chamber just to make it more convincing in a real-world dynamic scenario. The result shows that different concealed materials can be detected accurately with the beamforming algorithm. To the best of the authors’ knowledge, the proposed algorithm can effectively add up the target responses to obtain a clear and distinct image of the metallic and non-metallic targets.

The influence of the setup shape of a portable UWB system’s antennas in sport

Ultra-wide band (UWB) technology has become one of the most promising technologies of the future. It seems that the positioning of the antenna set influences the accuracy of the player’s performance. This study was aimed to assess the influence of two different antenna positioning system shapes: (i) octagonal installation and (ii) circular installation. A UWB technology was used to track a healthy and well-trained athlete’s (age: 38 years, mass: 76.34 kg, and height: 1.75 m) positioning. Overall, the data measured showed high accuracy in both shape setups in all trajectories assessed in static and dynamic conditions for all speed thresholds. However, the distance covered during jogging and sprinting showed poor accuracy for both shape setups. Moreover, the data measured showed high test-retest reliability and inter-device agreement in the static condition, regardless of the antenna setup shape. In conclusion, both the octagonal and circular antenna setup shape provided accurate data, but the measurement error associated within the setup shape seemed slightly different between the two systems.