Antenna Polarization Research Articles

Reliable and Resilient Wireless Communications in IoT-Based Smart Agriculture: A Case Study of Radio Wave Propagation in a Corn Field

In the past few years, one of the largest industries in the world, the agriculture sector, has faced many challenges, such as climate change and the depletion of limited natural resources. Smart Agriculture, based on IoT, is considered a transformative force that will play a crucial role in the further advancement of the agri-food sector. Furthermore, in IoT-based Smart Agriculture systems, radio wave propagation faces unique challenges (such as attenuation in vegetation and soil and multiple reflections) because of sensor nodes deployed in agriculture fields at or slightly above the ground level. In our study, we present, for the first time, several models (Multi-slope, Weissberger, and COST-235) suitable for planning radio coverage in a cornfield for Smart Agriculture applications. We received signal level measurements as a function of distance in a corn field (R3 corn stage) at 0.9 GHz and 2.4 GHz using two transmitting and two receiving antenna heights, with both horizontal and vertical polarization. The results indicate that radio wave propagation in a corn field is influenced not only by the surrounding environment (i.e., corn), but also by the antenna polarization and the positions of the transmitting and receiving antennas relative to the ground.

AcpAS: An Advanced Circularly Polarized Antenna Structure for an Airborne Relay Communication System

The airborne relay system is an important support for improving the stability of communication systems in complex electromagnetic environments. As a key component of the airborne relay system, the antenna needs to have characteristics such as high gain, dual circular polarization, wide beam coverage, and miniaturization. Based on the septum circular polarizer, this paper proposes a high-performance circularly polarized antenna structure suitable for airborne relay systems, named AcpAS. The structure consists of a coaxial feed port, a coaxial-to-waveguide transition, a septum circular polarizer, and a parabolic metal housing. Based on this structure, two antennas operating at 19.6 GHz to 21.6 GHz and 29.2 GHz to 31.2 GHz are designed in this paper. Simulated and measured results show that the two antennas have dual circular polarization characteristics, with beam coverage range of more than ±55° for gains higher than 0 dBi, and the radiation patterns exhibit good symmetry and wide-beam coverage characteristics.

Fabrication and Evaluation of an Electromagnetic Shielding Material Made of Randomly Chopped Tape Carbon Fiber/Polyamide 6 Composites

Abstract Environmental pollution generated by electromagnetic wave radiation has significantly increased including in automotive applications. Thus, material technology, including polymer composite, has attracted a reduction of the negative effect of electromagnetic radiation. In this study, carbon fiber reinforced polyamide thermoplastic (PA-6/CF) made of carbon fiber with polyamide 6 tape, in the shape of a half-box, was produced using the hot compression method with different tape-length, and then the electrical conductivity and electromagnetic shielding performance were evaluated. The electrical conductivity was obtained from the resistivity measured by using a digital multimeter. Whilst the effectiveness of electromagnetic interference shielding (EMI-SE) was investigated using two methods, calculation, and actual measurement. The result shows that there is a different electrical conductivity between base and slope area of the PA-6/CF box composite. It also was observed that the actual EMI shielding performance shows a corresponding increase with the length of chopped carbon fiber tape and has a higher value compared to the calculated EMI-SE. Then, the highest value obtained for actual EMI-SE was 54 dB for the PA6/CF composite with 20-mm tape length, in the frequency range 0.3 – 1 GHz, and on horizontal antenna polarization. Whereas the composite with 10-mm and 15-mm tape length was the lowest EMI- SE (38 dB) on vertical antenna polarization, in the same frequency range. Furthermore, the microscopy analysis depicted that there are more voids exist in the slope area compared with the base area of the PA-6/CF composites. Finally, the molded PA-6/CF composites can be used as the battery enclosures of electrical vehicles in automobiles.

URLLC CF Massive MIMO Systems With Dual Polarized Antennas and Hardware Impairments

URLLC CF Massive MIMO Systems With Dual Polarized Antennas and Hardware Impairments

A Single Radiator-Based Circularly Polarized Antenna for Indoor Wireless Communication Applications

A Single Radiator-Based Circularly Polarized Antenna for Indoor Wireless Communication Applications

Broadband polarization-adjustable antenna realized by waveguide circular polarizers.

A broadband polarization-adjustable antenna realized by two waveguide circular polarizers is proposed in this paper. The antenna consists of a rectangular-to-circular transition waveguide, two identically structured rectangular slot circular polarizers, and a conical horn, all connected in sequence. By rotating the two circular polarizers to specific angles, the antenna can switch among four polarization modes: horizontal polarization, vertical polarization, left-hand circular polarization, and right-hand circular polarization. The antenna polarization adjustment principle is thoroughly analyzed. Taking the X-band polarization-adjustable antenna as an example, simulation and optimization were performed, and a prototype was fabricated and measured. The antenna's reflection coefficient is below -18 dB across all polarization modes from 9.2 to 10GHz. In linear polarized modes, gains exceed 10.5 dBi. For circular polarized modes, the gains align with those of linear modes, with an axial ratio of less than 1 dB in the operating frequency band. The measured results are consistent with the simulation results, confirming its excellent polarization adjustment performance and potential for high power microwave applications.

A Quasi-Isotropic Probe for High-Power Microwave Field Measurement.

In the paper, a new design of a quasi-isotropic antenna for high-power electromagnetic (EM) field measurement is presented, along with its investigation into suitability. The measuring probe is intended for assessing pulsed microwaves, which cannot be measured by available meters due to the high value of electric field strength and short pulse duration. The measurement of such a strong field is required according to guidelines for protecting people against microwave fields, especially those emitted by radars. The proposed probe is based on the concept of dipole-diode detection. To enable high-power measurement, the receiving antenna is electrically "small," allowing diode detection within the diode square-law characteristics range. Additionally, the shortened dipole length minimizes the spatial integration error, which can be significant in the case of microwave measurement. To obtain the desired antenna polarization, a new dipole geometry was proposed. Fulfilling the requirement of measuring all incident EM field polarizations, the receiving antenna was based on three dipoles arranged within a specific "magic" angular arrangement, ensuring a suitable quasi-isotropic radiation pattern. The proposed probe can operate in a frequency range from 1 GHz to 12 GHz.

A Broadband MS-Based Circularly Polarized Antenna Array Using Sequential-Phase Feeding Network.

This paper introduces the design of a circularly polarized metasurface-based antenna array for C-band satellite applications that owns broadband operation and high gain characteristics. The single radiating element comprises a Y-shape patch and an above-placed 2 × 2 unit-cell metasurface. Further improvement in operating bandwidth and broadside gain is achieved by arranging four single elements in a 2 × 2 configuration and a sequential-phase feed network. A prototype has been fabricated and measured to validate the feasibility of the proposed antenna array. The measured operating bandwidth is 20% (4.50-5.50 GHz), which is an overlap between a -10 dB impedance bandwidth of 29.8% (4.50-5.99 GHz) and a 3 dB axial ratio bandwidth of 20% (4.50-5.50 GHz). Across this operating band, the peak broadside gain is 10.5 dBi. Compared with the recently published studies, the proposed array is a prominent design for producing a wide operating bandwidth and relatively high gains while maintaining the overall compact dimensions.

Design and Implementation of Transparent Cross‐Polarization Interference Compensation in a Wideband Dual‐Polarization Satellite Receiver

ABSTRACTIn this paper, simultaneous transmission on two orthogonal antenna polarizations in a polarization division multiplexing (PDM) fashion is studied for wideband satellite communication links using dual‐polarization satellite receivers for the purpose of doubling the data rate. In order to mitigate the cross‐polarization interference (XPI), a new digital blind and transparent XPI compensation method is proposed, coined as XPI correlation learning estimation and adaptive reduction (XPI‐CLEAR). The received signal‐to‐noise‐and‐interference ratio (SNIR) and packet‐error rate (PER) performance with this non‐data‐aided and non‐decision‐directed method is assessed in a comprehensively modelled XPI channel with effects such as depolarization due to atmospheric conditions, imperfect cross‐polarization discrimination (XPD) of the antennas at the transmitter and the receiver, memory effects due to frequency selectivity of the XPD, and differential frequency offset (DFO) between the two channels. The application of the XPI‐CLEAR method presents considerable energy efficiency improvements for all the studied XPI channel effects, and is particularly beneficial for higher order modulation. A low‐complexity hardware implementation with symbol rates up to 500 MBaud validates the XPI‐CLEAR method as a practical solution to increase the data rates of the satellite air interface and to achieve the doubling of the throughput of the satellite link by the use of PDM.

A Wideband Circularly Polarized Antenna Array Loaded With Dual-Layer Metasurface

A Wideband Circularly Polarized Antenna Array Loaded With Dual-Layer Metasurface

A Circularly Polarized Antenna Based on Narrowed Crossed Dipole for Smartphone Satellite Communication

A Circularly Polarized Antenna Based on Narrowed Crossed Dipole for Smartphone Satellite Communication

An Ultrawideband Circularly Polarized Antenna With Traveling-Wave Loop

An Ultrawideband Circularly Polarized Antenna With Traveling-Wave Loop

Near field food contamination detection technique employing a compact Antipodal Vivaldi antenna

This paper presents a simple yet robust technique for identification of the presence of contaminants in food samples by detecting the variation in the transmission coefficient (S21) in a near field measurement setup. A compact step-notched antipodal Vivaldi antenna with a frequency range of operation 3 - 18 GHz, and realized gain of 12.81 dB at 16 GHz having compact dimensions 60mm×40mm×0.51mm, i.e., 0.6×0.4×0.005λ03 (where λ0 is the free space wavelength at the lowest frequency of operation) is designed for contamination detection due to its compact size, high directivity and high boresight gain for near-field measurement. An equivalent image is constructed from the S - parameters, measured at different positions and different antenna polarizations over the frequency range of 3-18 GHz for metallic contaminants, i.e., iron ball and aluminum foil. An algorithm is developed for detection of contamination from the images using the reference case of no-contamination scenario. The proposed algorithm is validated using full-wave simulation.

Broadband Polarization Switchable Circularly Polarized Antenna With Stepped Radiating Loop

Broadband Polarization Switchable Circularly Polarized Antenna With Stepped Radiating Loop

Polarization conversion metasurface enabled broadband circularly polarized patch antenna

AbstractAssembling polarization conversion metasurface (PCM) and a simple patch antenna to realize a circularly polarized (CP) antenna with over 10% fractional bandwidth (BW) is a challenging task. A kind of PCM composed of S‐ring and grating structure that converts linearly polarized (LP) wave into CP wave in a broadband frequency from 8.74 to 12 GHz can address the challenge. The universality of the PCM in realizing antenna polarization conversion is verified by using a standard LP horn antenna. Then, we design a broadband LP rectangular patch antenna to demonstrate that the present PCM can be integrated with small antenna devices to achieve CP antenna. A broadband CP patch antenna with a 12.4% −10 dB BW and 11.3% 3 dB axial ratioBW is obtained. The antenna gain reaches 8.1 dB with the enhancement gain of 4.1 dB. The findings are very attractive for wireless communication, radar monitoring, and satellite systems because the proposed antenna has excellent broadband CP performances, simple structure, and easy fabrication.

Design of a Compact Circularly Polarized Implantable Antenna for Capsule Endoscopy Systems.

This research proposes a miniature circular polarization antenna used in a wireless capsule endoscopy system at 2.45 GHz for industrial, scientific, and medical bands. We propose a method of cutting a chamfer rectangular slot on a circular radiation patch and introducing a curved radiation structure into the centerline position of the chamfer rectangular slot, while a short-circuit probe is added to achieve miniaturization. Therefore, we significantly reduced the size of the antenna and made it exhibit circularly polarized radiation characteristics. A cross-slot is cut in the GND to enable the antenna to better cover the operating band while being able to meet the complex human environment. The effective axis ratio bandwidth is 120 MHz (2.38-2.50 GHz). Its size is π × 0.032λ02 × 0.007λ0 (where λ0 is the free-space wavelength of at 2.4 GHz). In addition, the effect of different organs such as muscle, stomach, small intestine, and big intestine on the antenna when it was embedded into the wireless capsule endoscopy (WCE) system was further discussed, and the results proved that the WCE system has better robustness in different organs. The antenna's specific absorption rate can follow the IEEE Standard Safety Guidelines (IEEE C95.1-1999). A prototype is fabricated and measured. The experimental results are consistent with the simulation results.

High‐gain dual‐wideband ±45° dual polarization (DWDP) antenna for indoor distributed antenna system (IDAS) applications

SummaryThis paper presents two different configurations of ±45° dual‐wideband dual‐polarized (DWDP) antennas. The antenna comprises eight end‐loaded broadband dipoles grouped into two sets based on the bands of operation. The high‐frequency dipoles are strategically placed within the low‐frequency ones to form the elementary unit. Further optimization has been performed on the elementary unit in terms of the radiator placement to suppress sidelobe levels for array formation. Both configurations are meticulously fabricated using an all‐metal structure, demonstrating durability and the simplicity of fabrication. The antenna designs achieve ±45° polarization, high gain, satisfactory cross‐polarization discrimination (XPD), and wide impedance bandwidth covering 0.67–1.04 GHz and 1.54–3 GHz bands. Despite the nested configuration, mutual coupling is well within acceptable limits. Formation of the array based on the optimum elementary unit has been investigated by simulation, revealing reasonable gain enhancement and low sidelobe levels across all bands. This comprehensive approach yields a robust, high‐performing antenna configuration suitable for indoor distributed antenna system (IDAS) applications.

Ultra-Wideband Dual-Circularly Polarized Crossed-Dipole Antenna With Stripline Coupler and Parasitic Elements for Vehicular Sensing and Communications

Ultra-Wideband Dual-Circularly Polarized Crossed-Dipole Antenna With Stripline Coupler and Parasitic Elements for Vehicular Sensing and Communications

A Miniaturized Wideband Circularly Polarized Antenna Based on Tightly Coupled Monopole

A Miniaturized Wideband Circularly Polarized Antenna Based on Tightly Coupled Monopole

A Wideband Circularly Polarized Antenna With a Nonuniform Metasurface Designed via Multiobjective Bayesian Optimization

A Wideband Circularly Polarized Antenna With a Nonuniform Metasurface Designed via Multiobjective Bayesian Optimization