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An antipodal Vivaldi monopole radiator is employed in an innovative wideband planar slotted meander antenna. A quarter-wave microstrip feed is coupled to the antenna for a ground reflector plane over a meander line with five right and left antipodal Vivaldi (RLAV) slots on either side and a series of Z, inverted U and inverted Z-shaped turns. The FR4 substrate with a relative permittivity of 4.4 and modest dimensions of 50 × 20 × 1.6 mm3 is used to implement the proposed antenna. A 17.39% fractional bandwidth of -29.10dB (S11

Meander Line Antenna (MLA) is widely employed in compact electronic devices, such as cellular phones and WLAN terminals, owing to its electrically small size. To facilitate practical antenna design, essential equations encompassing self-resonant structure, input resistance, antenna efficiency, and Q factor have been systematically developed. However, the prior self-resonant equations included only inductive reactance (XC), neglecting the capacitive reactance (XD) equation. This manuscript addresses this gap by introducing new design equations, presenting a newly derived $\rm X_{D}$ equation and an improved Q factor expression. The inadequacies of the existing Q factor equation, reliant on the radius of a sphere encompassing the antenna, are addressed by proposing a more fitting expression that incorporates antenna structural parameters using the ratio of reactance to resistance. The overview of existing design equations sets the stage for the introduction of these newly developed equations. To assess the accuracy of electromagnetic (EM) simulation results, a comparative analysis is conducted between simulated and theoretically calculated input resistance values. The derivation of new reactance equations involves the development of $\rm X_{C}$ equations based on electromagnetic theory. The $\rm X_{D}$ equation is established by deriving the stored charge equation from electrical near-field distributions obtained through EM simulations. By applying the relationship between charge and capacitance, a new $\rm X_{D}$ equation is obtained. Subsequently, a new self-resonant equation is derived, and the validity of the newly derived equations is confirmed through EM simulation results, ensuring their accuracy. Two MLA prototypes, with lengths of 0.05 and 0.1 wavelengths at 405 MHz, are fabricated and experimentally validated. Smith chart measurements confirm the self-resonant condition and input resistance. By correlating with the VSWR characteristics, the obtained Q factor of approximately 100 aligns successfully with the results from the reactance equation. The antenna gain is verified at −7.7 dBi and −3.5 dBi for antennas with lengths of 0.05 and 0.1 wavelengths, respectively. These findings establish the practical applicability of the proposed equations for antenna design and elucidate the performance of practical antennas.

The 700 MHz public safety spectrum is released for commercial wireless and safety communication wearable applications (CWSC-WA). However, the 700 MHz band need a larger aperture for an efficient radiation due to a larger wavelength. In this paper, we have systematically developed a novel miniature omnidirectional 700 MHz antenna for the CWSC-WA. Over 40% miniaturization is realized by truncating the ground plane and a meander line inspired radiator compared to a conventional rectangular patch antenna. The truncation of the ground plane also yields a perfect omnidirectional radiation pattern desired for the CWSCA. Considering current and future demands of wearable electronics and virtual reality, the antenna is made on a flexible substrate and conformity analysis is also performed. The prototype of the antenna is developed and simulated results are verified in planar as well as conformal configurations.

This work states triband meander line base antenna with asymmetric Co-planar wave guide feed applicable for Wi-MAX, North American Public safety and Satellite Applications across the operating frequency of (5.3 GHz, 6.6 GHz, and 8.1 GHz). The proposed antenna with a compact size of 25 × 25 × 1.6 mm3 is designed using Ansys electronics desktop software over an FR-4 epoxy substrate. Coplanar Wave guide (CPW) is printed on either side of the antenna to the meander-type patch. To minimize the S-parameters of the antenna, slots are placed in the CPW. The antenna performance was evaluated based on return loss, operational bandwidth, gain, VSWR and radiation pattern characteristics. During measurement, return loss was measured by reading the S(1,1) port reflection constant parameter, which was found to be < −10 dB. As a result, the proposed antenna shows an efficiency value of > 80% across the operating frequency. The presented antenna results are analyzed experimentally through ANRITSU-MS2037C combinational analyzer. It is observed that the measured results are confirmed with the simulated results. [ABSTRACT FROM AUTHOR]

Protected wetlands such as deltas, lakes or rivers provide a sanctuary for many endangered species. In order to protect these areas from illegal human interventions, it is necessary to monitor the unauthorized entrance of motor boats. In order to mitigate such an impact, we have developed a network of floating beacons for underwater acoustic monitoring, using LoRa communication modules operating at 433 MHz. Such beacons should be equipped with compact antennas. In this paper, we use a genetic algorithm approach to design the compact, monopole antennas required for the beacons; size constraints would apply not only to the radiating element but also to the ground plane. Although the antenna input is unbalanced, such a small ground plane may yield common mode currents on the antenna feeder, which distort the radiation pattern of the antenna. In order to investigate the effect of the common mode currents, we developed a distance averaging method, while, for characterizing the antenna, we used a single-antenna method. For the experimental validation of the system in real conditions, a continuous monitoring of the lake was carried out. During the monitoring, multiple events generated by incursions of motor boats were successfully detected and recorded. [ABSTRACT FROM AUTHOR]

The use of LoRa (Long Range) wireless communication as an Internet-of-Things (IoT) protocol has great potential. This technology works in the unlicensed ISM band and covers all the globe with different frequencies, which can improve the wide and rapid spread of information. To obtain global IoT coverage using LoRa, the use of satellite networks is mandatory. The development of nanosatellites, mostly in the CubeSat form factor, for communication applications in general and LoRa communication in particular, is currently increasing. To date, these satellites usually use linear wire deployable antennas for communication. However, deployable mechanical systems present the risk of failure during the mission. In fact, one-unit CubeSat geometry allows a very small space (10 cm * 10 cm * 0.06 cm) for the antenna. Since the size of the antenna is proportional to wavelengths, the antenna size is a large problem for low frequencies, especially in the UHF band. For this reason, planar antennas are an attractive solution for CubeSat communications. This work presents the design of a miniaturized printed monopole meander line antenna working at a frequency of 920 MHz. The novelty of the design is obtained by placing the meander line and the ground plane onto similar sides of the antenna. The meander line allows reduction of the antenna size by a factor of λ/5 for the selected operating frequency. The structure of this proposed antenna has a low profile, and a small size of 50 * 80 * 1.635 mm3 or about 0.153λ 0 * 0.245 λ 0. It has an S11 magnitude of –33.53 dB obtained by simulation and S11 magnitude of −19 dB obtained through experimental measurements. The simulation results also show that the proposed meander line antenna will produce an omnidirectional radiation pattern and a maximum gain of 1.8 dB. [ABSTRACT FROM AUTHOR]

Protected wetlands such as deltas, lakes or rivers provide a sanctuary for many endangered species. In order to protect these areas from illegal human interventions, it is necessary to monitor the unauthorized entrance of motor boats. In order to mitigate such an impact, we have developed a network of floating beacons for underwater acoustic monitoring, using LoRa communication modules operating at 433 MHz. Such beacons should be equipped with compact antennas. In this paper, we use a genetic algorithm approach to design the compact, monopole antennas required for the beacons; size constraints would apply not only to the radiating element but also to the ground plane. Although the antenna input is unbalanced, such a small ground plane may yield common mode currents on the antenna feeder, which distort the radiation pattern of the antenna. In order to investigate the effect of the common mode currents, we developed a distance averaging method, while, for characterizing the antenna, we used a single-antenna method. For the experimental validation of the system in real conditions, a continuous monitoring of the lake was carried out. During the monitoring, multiple events generated by incursions of motor boats were successfully detected and recorded.

The 700 MHz public safety spectrum is released for commercial wireless and safety communication wearable applications (CWSC-WA). However, the 700 MHz band need a larger aperture for an efficient radiation due to a larger wavelength. In this paper, we have systematically developed a novel miniature omnidirectional 700 MHz antenna for the CWSC-WA. Over 40% miniaturization is realized by truncating the ground plane and a meander line inspired radiator compared to a conventional rectangular patch antenna. The truncation of the ground plane also yields a perfect omnidirectional radiation pattern desired for the CWSCA. Considering current and future demands of wearable electronics and virtual reality, the antenna is made on a flexible substrate and conformity analysis is also performed. The prototype of the antenna is developed and simulated results are verified in planar as well as conformal configurations., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

A printed edge-fed counterpart of the wire Bruce array antenna, for frequency scanning applications, is presented in this paper. The unit-cell of the proposed antenna consists of bowtie and semi-circular elements to achieve wide bandwidth from below 22 GHz to above 38 GHz with open-stopband suppression. The open-stopband suppression enables a wide seamless scanning range from backward, through broadside, to forward endfire. A sidelobe threshold level of −10 dB is maintained to evaluate efficient scanning performance of the antenna. The antenna peak realized gain is 15.30 dBi, and, due to its compact size, has the ability to scan from −64° to 76°.

In this paper, two element multiple input-multiple output (MIMO) meander line antenna systems with improved isolation performance and compact size are proposed and fabricated in WLAN frequency band. To increase isolation among antenna elements, a novel metamaterial spiral S-shaped resonator is embedded between two radiating elements. The proposed resonator has planar configuration and miniaturized size and is capable of blocking electromagnetic propagation between antenna elements by exhibiting negative effective permeability in the desired frequency band. To illustrate and evaluate the design process, two design samples are fabricated and tested in WLAN frequency band and the agreement among measurement and simulation results approves the design method. In the frequency range of 2.38-2.48 GHz, some MIMO communication system requirements like total active reflection coefficient, envelope correlation coefficient and capacity loss are tested on design samples which show satisfactory results, so this method can be employed in designing array antennas for small mobile communication systems. The designed MIMO antenna systems separated by 13.8 mm (less than λ/9), has better than − 40 dB isolation coefficient and near zero correlation coefficient and capacity loss at the operating frequency (2.4 GHz). [ABSTRACT FROM AUTHOR]

In this work, we introduce a novel series-feed 4-element antenna array that provides wider bandwidth, improved co and cross-polarization isolation, and higher gain. To achieve these three research objectives of miniaturization, bandwidth enhancement, and co-cross polarization isolation improvements, we implemented three different technologies including meandering the radiator, integrating a neutralization line, and antipodal-Vivaldi defects in the ground plane. By using these techniques in a step-wise manner, we were able to enhance the gain of a single-element meander line array radiator antenna by 5.7 dBi and suppress cross-polarization by 7.2 dB at the main lobe. The proposed 4-element antenna array has an overall size of 3. 867 λ g × 3. 867 λ g × 0. 052 λ g . The antenna provides a measured bandwidth of 9%, covering the 27.2 GHz to 30 GHz band, with a Half-power Beamwidth (HPBW) of 33 ∘ and a peak measured gain of 11.426 dBi. The main lobe is located at 35 ∘. We conducted a precise analysis and detailed discussion of the impact of various design parameters. The presented analysis and design were validated through prototyping and testing. [ABSTRACT FROM AUTHOR]

Due to their high-frequency ratios, sub-6-GHz and millimeter-wave bands are becoming crucial for fifth-generation (5G) smartphone applications for achieving beam steering and high gain performance without using additional separate antenna elements. This paper presents compact integrated antenna array modules for simultaneous operation in the 3.5 GHz (sub-6 GHz) and (26 GHz) millimeter-wave frequencies. The proposed integrated single antenna element is composed of a microstrip patch antenna, a low-pass filter, and a meandered line-based antenna. The dimensions of the proposed compact integrated antennas are 0.6363 λ g × 0. 2423 λ g × 0. 0147 λ g . The proposed antenna provides wide bandwidth characteristics in both operating frequencies with a -10 dB bandwidth of 500 MHz and 4.5 GHz in the sub-6 GHz and millimeter-wave bands, respectively. The effects of the smartphone on scattering parameters were analyzed. Further, we have studied the safety of smartphone users in terms of specific absorption rate (SAR) and power density (PD). The SAR and PD of the proposed antenna were found under safety limits. Additionally, the proposed antenna array modules were fabricated on a low-cost FR-4 substrate for validation of the simulation results, and a good agreement was found among them. The proposed antenna array packages are excellent candidates for modern 5G smartphones because they provide excellent features such as wide bandwidth characteristics and high gain with wide beam scanning features, and can integrate 3.5 GHz (sub-6 GHz) and (26 GHz) millimeter-wave bands with a high-frequency gap in a small structure. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a brain disorder that eventually causes memory loss and the ability to perform simple cognitive functions; research efforts within pharmaceuticals and other medical treatments have minimal impact on the disease. Our preliminary biological studies showed that Repeated Electromagnetic Field Stimulation (REFMS) applying an EM frequency of 64 MHz and a specific absorption rate (SAR) of 0.4 - 0.9 W/kg decrease the level of amyloid- β peptides (A β ), which is the most likely etiology of AD. This study emphasizes uniform E/H field and SAR distribution with adequate penetration depth penetration through multiple human head layers driven with low input power for safety treatments. In this work, we performed numerical modeling and computer simulations of a portable Meander Line antenna (MLA) to achieve the required EMF parameters to treat AD. The MLA device features a low cost, small size, wide bandwidth, and the ability to integrate into a portable system. This study utilized a High-Frequency Simulation System (HFSS) in the design of the MLA with the desired characteristics suited for AD treatment in humans. The team designed a 24-turn antenna with a 60 cm length and 25 cm width and achieved the required resonant frequency of 64 MHz. Here we used two numerical human head phantoms to test the antenna, the MIDA and spherical head phantom with six and seven tissue layers, respectively. The antenna was fed from a 50-Watt input source to obtain the SAR of 0.6 W/kg requirement in the center of the simulated brain tissue layer. We found that the E/H field and SAR distribution produced was not homogeneous; there were areas of high SAR values close to the antenna transmitter, also areas of low SAR value far away from the antenna. This paper details the antenna parameters, the scattering parameters response, the efficiency response, and the E and H field distribution; we presented the computer simulation results and discussed future work for a practical model., Competing Interests: Conflicts of Interest The authors declare no conflicts of interest regarding the publication of this paper.

ABSTRACT A thin, single substrate layered, dual directionally isolated band Meander line antenna (MLA) with connected ends, widened near the feed area, loaded by a U-slot in the patch layer, and by a modification from complementary split ring resonator (CSRR) in the ground layer, is presented for WLAN applications. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:895-901, 2016 [ABSTRACT FROM AUTHOR]

We present an antenna-in-package system integrated with a meander line antenna based on low temperature co-fired ceramic (LTCC) technology. The proposed system employs a meander line patch antenna, a packaging layer, and a laminated multi-chip module (MCM) for integration of integrated circuit (IC) bare chips. A microstrip feed line is used to reduce the interaction between patch and package. To decrease electromagnetic coupling, a via hole structure is designed and analyzed. The meander line antenna achieved a bandwidth of 220 MHz with the center frequency at 2.4 GHz, a maximum gain of 2.2 dB, and a radiation efficiency about 90% over its operational frequency. The whole system, with a small size of 20.2 mm×6.1 mm×2.6 mm, can be easily realized by a standard LTCC process. This antenna-in-package system integrated with a meander line antenna was fabricated and the experimental results agreed with simulations well. [ABSTRACT FROM AUTHOR]

In this paper, the compact antenna with three folded patches for use in a number of bands of LTE, WCDMA, US-PCS, and WLAN at the same time is proposed. As the changes in widths of the 3 patches to widen the insufficient bandwidth are given, it is optimized for S11< -6 dB(VSWR<3). The CPW with a number of advantages is used in the proposed antenna. The proposed antenna is designed and fabricated with FR4 substrate to the size of 44.9 × 35 × 1 mm3. Fabricated antenna has within S11<-6 dB under operating bands. And measured characteristics of radiation patterns and gains are shown under operating bands. [ABSTRACT FROM AUTHOR]

Fixed area meander line antennas designed on a 5 × 5 rectangular grid were optimized for efficiency and resonant frequency. The Pareto front was developed using ant colony optimization and the numerical electromagnetic code. The lowest frequency antenna fits an area of 0.11λ0 × 0.05λ0 with an efficiency of 88%. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [ABSTRACT FROM AUTHOR]

A compact, wide bandwidth, wide beamwidth resonant microstrip meander line antenna element is reported for active phased array applications. The antenna element offers a return loss better than -10 dB over a bandwidth of 12% in S-band with a beamwidth of 130° in E-plane. The element has been tested in an array for its wide-angle scan performance. Simulated and measured results are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1737–1740, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23531 [ABSTRACT FROM AUTHOR]

The feasibility is investigated using three dimensional folded dipole antennas as a data-telemetry implantable receiving antenna in a dual-unit retinal prosthesis to restore partial vision to the blind. Three dimensional designs are explored in an effort to enhance certain antenna characteristics such as bandwidth and maximum gain while reducing the planar footprint size in comparison to its two dimensional equivalent. The current vector alignment between the three dimensional layers are examined through folding and rotating the dipole arms with respect to each other to fully optimize the antenna's characteristics. The performance of the 2D and 3D antennas were compared in simulations and further examined by fabricating and characterizing the performance in a transmit/receive system in air and inside eye phantoms. Results show that three-dimensional antennas can provide larger bandwidth while being physically smaller than the correspondent two-dimensional ones, thus providing larger channel capacity that could lead to a system with an increased number of stimulating electrodes. [ABSTRACT FROM AUTHOR]

Radio-frequency identification technology, based on the reader/tag paradigm, is quickly permeating several aspects of everyday life. The electromagnetic research mainly concerns the design of tag antennas having high efficiency and small size, and suited to complex impedance matching to the embedded electronics. Starting from the available but fragmented open literature, this paper presents a homogeneous survey of relevant methodologies for the design of UHF passive tag antennas. Particular care is taken to illustrate, within a common framework, the basic concepts of the most-used design layouts. The design techniques are illustrated by means of many noncommercial examples. [ABSTRACT FROM AUTHOR]

Demands for extremely small antennas to be used in radiofrequency identification tags for ubiquitous communication have increased. Examples of very small antennas utilizing meander line structures are seen. To date, important studies have been carried out on basic design and on improvement of the radiation efficiency by a folded configuration. Most of the structures studied have dimensions of more than 0.1 wavelength. For the demands of ultracompact antennas, this paper deals with meander line antennas whose dimensions are less than 0.1 wavelength. First, the parameters for resonant configurations are derived for antennas with dimensions of 0.1 to 0.025 wavelength. Next, the radiation resistance and the ohmic resistance are studied in the folded structures. First, through a transmission line model analysis, it is shown that the step-up ratios of radiation and ohmic resistances in the case of folded structures are different. In addition, these resistances that are basic values of electrical performances are derived through electromagnetic simulations. Further, in order to confirm the validity of the numerical results and the realizable performance, antennas with dimensions of 0.1 and 0.05 wavelength were fabricated. Electrical characteristics are compared, and good agreements are found. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(8): 1–11, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20204 [ABSTRACT FROM AUTHOR]

A printed edge-fed counterpart of the wire Bruce array antenna, for frequency scanning applications, is presented in this paper. The unit-cell of the proposed antenna consists of bowtie and semi-circular elements to achieve wide bandwidth from below 22 GHz to above 38 GHz with open-stopband suppression. The open-stopband suppression enables a wide seamless scanning range from backward, through broadside, to forward endfire. A sidelobe threshold level of −10 dB is maintained to evaluate efficient scanning performance of the antenna. The antenna peak realized gain is 15.30 dBi, and, due to its compact size, has the ability to scan from −64° to 76°. [ABSTRACT FROM AUTHOR]