Showing papers in "Progress in Electromagnetics Research C in 2016"

Circularly Polarized 2×2 MIMO Antenna for WLAN Applications

Abstract: A 2 × 2 circularly polarized (CP) MIMO antenna is proposed to resonate at 5.8 GHz IEEE 802.11 WLAN band for non-line of sight (NLOS) communication. The proposed design achieves circular polarization with two optimized 90◦ apart rectangular slots etched at the center of a truncated rectangular patch. The proposed MIMO covers 5.49–6.024 GHz frequency band. The achieved isolation between two ports is more than 33 dB. The gain at the 5.8 GHz resonant frequency is 5.34 dBi. The diversity performance in terms of gain, ECC, and MEG has been reported.

A 2 × 2 Dual-Band MIMO Antenna with Polarization Diversity for Wireless Applications

Abstract: A compact 2×2 dual-band MIMO antenna is proposed with polarization diversity technique for present wireless applications. The proposed design combines the horizontally and vertically polarized radiating elements. The effect of mutual coupling between radiating elements is reduced by partially stepped ground (PSG) and by the orthogonal placement of antenna elements. The whole configuration is designed over a substrate of size 70 × 70 mm 2 . The measured frequency bands extend from 2.408 to 2.776 GHz and 4.96 to 5.64 GHz frequencies with SWR < 2. The measured isolation is more than 21 dB between adjacent and diagonal ports. The measured peak gains at 2.54 GHz, and 5.26 GHz resonant frequencies are 3.98 dBi and 4.13 dBi, respectively. The designed MIMO covers LTE bands (7/38/41), WLAN bands (2.4/5.2 GHz), and WiMAX band (2.5/5.5 GHz). The diversity performances in terms of peak gain, ECC, and MEG have also been reported.

Triple Band Notched UWB Antenna Design Using Electromagnetic Band Gap Structures

Abstract: A circular monopole antenna for ultra wideband (UWB) applications with triple band notches is proposed. The proposed antenna rejects worldwide interoperability for microwave access WiMAX band (3.3 GHz–3.8 GHz), wireless local area network WLAN band (5.15 GHz–5.825 GHz) and X-Band downlink satellite communication band (7.1 GHz–7.9 GHz). The antenna utilises mushroomtype and uniplanar Electromagnetic Band Gap (EBG) structures to achieve band-notched designs. The advantages of band-notched designs using EBG structures such as notch-frequency tuning, triple-notch antenna designs and stable radiation pattern are shown. The effect of variation of EBG structure parameters on which notched frequency depends is also investigated. Fabricated and measured results are in good agreement with simulated ones.

Rectangular dielectric resonator antenna array for 28 GHz applications

Abstract: In this paper, a Rectangular Dielectric Resonator Antenna (RDRA) with a modified feeding line is designed and investigated at 28 GHz. The modified feed line is designed to excite the DR with relative permittivity of 10 which contributes to a wide bandwidth operation. The proposed single RDRA has been fabricated and mounted on a RT/Duroid 5880 (er = 2.2 and tanδ = 0.0009) substrate. The optimized single element has been applied to array structure to improve the gain and achieve the required gain performance. The radiation pattern, impedance bandwidth and gain are simulated and measured accordingly. The number of elements and element spacing are studied for an optimum performance. The proposed antenna obtains a reflection coefficient response from 27.0 GHz to 29.1 GHz which cover the desired frequency band. This makes the proposed antenna achieve 2.1 GHz impedance bandwidth and gain of 12.1 dB. Thus, it has potential for millimeter wave and 5G applications

Design of High-Isolation Compact MIMO Antenna for UWB Application

Abstract: In this paper, a compact multiple-input-multiple-output (MIMO) antenna is proposed for ultra wideband (UWB) communication. The UWB MIMO antenna consists of two identical monopole antenna elements with a comb-line structure on the ground plane to improve impedance matching and enhance isolation. Simulation and measurement have been analysed in terms of reflection coefficient, mutual coupling, dispersion diagram, radiation pattern, peak gain, efficiency and envelope correlation coefficient. Results show that the antenna has an impedance bandwidth larger than 3.1-10.6 GHz, mutual coupling between the two ports lower than −25 dB and envelope correlation coefficient less than 0.001 across the UWB band. The proposed antenna has a compact size of 26 × 31 mm 2 .A ll the measured and calculated results show that the proposed UWB MIMO antenna is a good candidate for UWB MIMO systems.

Design and Analysis of a Frequency Reconfigurable Microstrip Patch Antenna Switching Between Four Frequency Bands

Abstract: An effective design of a novel, compact, single feed, dual patch frequency reconfigurable Microstrip Patch Antenna (MPA) for wireless communication systems is proposed and studied in this paper. Fundamental structure of the antenna consists of a rectangular patch and a U-shaped patch. This antenna occupies a compact volume of 86.3mm × 50mm × 1.5875 mm (6850.6 mm3) including ground plane. Switching among four different frequencies is obtained by varying effective length of antenna. Effective length is changed by placing three PIN diodes at different positions in the slot present between two patches of the antenna. Variations in effective length perturb the surface current paths and hence change current density on the conducting patches. By changing states of PIN diodes, the proposed antenna could be switched to 1.87 GHz, 3.55 GHz, 3.67 GHz and 5.6 GHz frequencies. Antenna is simulated in High Frequency Structure Simulator (HFSS) Version 13.0, and a prototype of the simulated antenna with DC biasing circuit is fabricated on a flame retardant (FR-4) Epoxy substrate. The antenna is fed by an inset microstrip line which provides impedance matching. The prototype is tested for its performance analysis. A good agreement is obtained between measured and simulated results. Simulated and measured results show that the antenna provides return loss less than −10 dB assuring good match in absence of any matching network at all frequencies. Effect of changing the position of PIN diodes on resonance frequencies is also studied. The proposed antenna provides benefits such as multifunction operation and symmetry of radiation pattern upon switching between different frequencies.

A Compact Dual Band Polyimide Based Antenna for Wearable and Flexible Telemedicine Devices

Abstract: Recent wearable health monitoring systems use multiple biosensors embedded within a wireless device. In order to reliably transmit the desired vital signs in such systems, a new set of antenna design requirements arise. In this paper, we present a flexible, ultra-low profile, and compact dual band antenna. The proposed design is suitable for wearable and flexible telemedicine systems and wireless body area networks (WBANs). The antenna is inkjet printed on a 50.8µ mP olyimide Kapton substrate and fed by a Coplanar Waveguide (CPW). The proposed design has the merits of compactness, light weight, wide bandwidth, high efficiency, and mechanical stability. The performance of the antenna is also characterized against bending and rolling effects to assess its behaviour in a realistic setup since it is expected to be rolled on curved surfaces when operated. The antenna is shown to exhibit very low susceptibility to performance degradation when tested against bending effects. Good radiation characteristics, reduced fabrication complexity, cost effectiveness, and excellent physical properties suggest that the proposed design is a feasible candidate for the targeted application.

CPW-Fed Phi-Shaped Monopole Antenna for Super-Wideband Applications

Abstract: A compact Phi-shaped monopole antenna for super wideband applications is proposed. It consists of a Phi-shaped radiator derived from a conventional elliptical monopole and quarter elliptical CPW ground plane. An impedance bandwidth from 3.5 to 37.2 GHz is achieved with a ratio bandwidth of 10 : 1. It provides an average peak realized gain of 3.5 dB with a group delay of less than 0.5 ns. The proposed antenna structure provides large bandwidth with the advantage of miniaturized dimensions compared to other SWB antenna structures.

Miniaturized Wearable Fractal Antenna for Military Applications at VHF Band

Abstract: This paper presents the design and development of Koch fractal dipole antenna for wearable applications at 450 MHz. Common jeans cotton is used as a flexible substrate material having a dielectric constant of 1.6 for the design and fabrication of the proposed antenna. Increasing the number of iterations increases the number of sections, which eventually results in 32% reduction in size. Size miniaturization is obtained using second iteration Koch geometry with the antenna bandwidth of 10%, and the return loss of �25 dB is achieved under the flat condition. The investigations are to characterize the antenna not only in flat condition, but also under different bendings and crumpling conditions. The proposed Koch fractal antenna is close to the proximity of the body, and the absorption of electromagnetic power on human body is also examined. It is found that the Specific Absorption rate (SAR) is much below a safety level of 0.119 W/kg and hence suitable for wearable applications.

A Dual-Band Low-Profile Metasurface-Enabled Wearable Antenna for WLAN Devices

Abstract: This paper presents a compact, low-profile, wearable dual-band antenna operating in the Wireless WLAN band of 5.15 ∼ 5.25 GHz and 5.72 ∼ 5.83 GHz. The proposed antenna is composed of a planar monopole and underneath three by three array arrangement of Jerusalem Cross (JC) structure metasurface. The simulated results show that the integrated antenna express 4.09% and 4.14% impendence bandwidths, increased gain up to 7.9 dB and 8.2 dB, front to back (FB) ratio achieved to 20 dB and 18 dB at the two frequencies, respectively. The measured results agree well with simulations. In addition, the metasurface not only is equivalent to a ground plane for isolation, but also acts as the main radiator, which enables a great reduction in the specific absorption rate (SAR). Furthermore, because of a compact solution, the proposed integrated antenna can be a promising device for various wearable systems.

Dual Notch UWB Fork Monopole Antenna with CRLH Metamaterial Load

Abstract: A novel fork monopole antenna is presented using metamaterial structures. The prototype monopole antenna consists of split-ring-resonators (SRR) as an electric-LC resonator and small ground. To prove the concept, the prototype antenna is designed and fabricated for wireless communication systems. The monopole structure makes ultra wideband (UWB) impedance bandwidth condition for 2- 12 GHz. On the other hand, the prototype antenna shows dual notch band characteristics at 3.5-4.5 GHz and 5.3-6 GHz for WiMAX and WLAN rejection. The prototype antenna radiates omnidirectionally and has a gain altered between −4.5 and 6.2 dBi in 2.5-12 GHz, with an average gain of 4.2 dBi. The metamaterial model is suggested for the CRLH (ELC) resonator, and in addition, the parametric study for CRLH (ELC) resonator is presented for clarification of its manner on resonance controlling. Here, the final model antenna is fabricated on an FR-4, and experimental results are compared with simulations.

A Novel Compact Fractal Ring Based Cylindrical Dielectric Resonator Antenna for Ultra Wideband Application

Abstract: This paper presents a novel compact Koch snowflake fractal ring based Dielectric Resonator Antenna (DRA) for ultra wideband application. Firstly, Koch snowflake fractal geometry is implemented on the conventional Cylindrical Dielectric Resonator Antenna (CDRA). Further, the performance of the DRA is enhanced by fractal ring created on the snowflake geometry. With the application of the fractal and the fractal ring geometry, the Q-factor of DRA is reduced, thus the bandwidth of DRA is increased. The proposed antenna offers a wide impedance bandwidth of 90% ranging from 4.7 GHz–12.4 GHz. The effect of the fractal geometry enhances the gain of DRA. The proposed antenna achieves radiation efficiency more than 78%, throughout the bandwidth. Interestingly, the proposed configuration reduces the DRA volume by 76.63% with reduced volume of 7.91 cm3. The experimental verification of the proposed structure shows good agreement between simulated and measured results.

A Compact ACS-Fed Mirrored L-Shaped Monopole Antenna with SRR Loaded for Multiband Operation

Abstract: In this paper, a compact asymmetric coplanar strip (ACS)-fed mirrored L-shaped monopole antenna is presented. The proposed design consists of three mirrored L-shaped branches and a split ring resonator (SRR) loaded beneath the substrate, which are responsible for achieving multiband characteristics, compactness and good impedance matching. The proposed antenna with a compact dimension of 22 × 16.08 × 1. 6m m 3 is fabricated and tested. The experiment result indicates that the proposed design, having −10 dB impedance bandwidth of 200, 670 and 530 MHz for 2.44, 5.3 and 8.2 GHz, respectively, covers 2.4/5.2/5.8 GHz WLAN, 5.5 GHz WiMAX and 8.2 GHz ITU band. It has good radiation characteristics for both E-plane and H-plane in all the desired frequency bands and produces good performances compared to the existing antenna designs in the literature. The loaded SRR structure performance is validated through negative permeability extraction and various parametric studies.

A Novel Proximity Fed Gap Coupled Microstrip Patch Array for Wireless Applications

Abstract: Design and development of a novel dual-band microstrip patch array antenna suitable for WLAN and WiMAX applications are presented. The proposed array configuration is obtained by employing two parasitic patches gap coupled to the driven elements of a single layer proximity fed 2 × 1 microstrip patch array configuration. The proposed dual-band array has the advantages of enhanced bandwidth and gain. The feed patches are excited by proximity feeding method and the parasitic patches are excited by gap-coupling. This microstrip patch array provides resonances at two frequencies of 2.584 GHz (2.412-2.629 GHz) and 3.508 GHz (3.469-3.541 GHz). This novel configuration has a measured gain of 8.51 dBi and 5.8 dBi in lower and upper bands with an impedance bandwidth of 8.16% and 2.05% respectively. Additionally, to enhance the front to back ratio at the upper resonant frequency, a metal plate is placed at the back side of the array antenna. This modified proximity fed gap coupled array provides directional radiation patterns with improved gains. Re-configurability in the form of beam steering is obtained in the modified array configuration by varying the air gap between the ground plane and metal plate. The simulated results are in good agreement with the experimental ones.

An UWB Printed Antenna for Partial Discharge UHF Detection in High Voltage Switchgears

Abstract: As important fundamental equipment, high voltage switchgears are widely used in electric power systems and directly relative to the power reliability and quality. Partial discharge (PD) online monitoring is one of the most effective methods used for insulation testing and diagnosis in high voltage switchgears and power systems. This paper proposes a unique ultra-wide-band (UWB) antenna with high performance for PD ultra-high-frequency (UHF) detection in high voltage switchgears. Actual PD experiments were carried out, and the designed antenna was used for PD measurements. The measured results demonstrate that the proposed antenna has wide work frequency band, good omnidirectional radiation patterns and appreciable gain, which indicate that the proposed antenna is suitable for UHF online monitoring of PDs in high voltage switchgears.

A Compact Dual-Band Dual-Polarized Antenna for Base Station Application

Abstract: A compact dual-band dual-polarized antenna is proposed in this paper. The two pair dipoles with strong end coupling are used for the lower frequency band, and cross-placed patch dipoles are used for the upper frequency band. The ends of the dipoles for lower frequency band are bent to increase the coupling between adjacent dipoles, which can benefit the compactness and bandwidth of the antenna. Breaches are introduced at the ends of the dipoles of the upper band, which also benefit the compactness and matching of the antenna. An antenna prototype was fabricated and measured. The measured results show that the antenna can cover from 790MHz to 960MHz (19.4%) for lower band and from 1710MHz to 2170MHz (23.7%) for upper band with VSWR < 1.5. It is expected to be a good candidate design for base station antennas.

A Wide Spectrum Sensing and Frequency Reconfigurable Antenna for Cognitive Radio

Abstract: A novel hybrid antenna capable of both spectrum sensing and frequency reconfigurability is proposed in this paper. The proposed hybrid antenna senses spectrum over a wide frequency range from 1GHz–12 GHz and accordingly reconfigures its operating frequency in any of the four different frequencies, i.e., 2.1 GHz, 2.96 GHz, 3.5 GHz and 5GHz. Since wideband response for spectrum sensing and each frequency state works independently, there is no interference among various signals. The wideband response for spectrum sensing is obtained by exciting semicircular arc having staircase-shaped slot in the ground plane. Frequency reconfiguration is achieved by electronic switching among various matching stubs. Both simulated and experimental results for the return loss, gain and radiation patterns are presented. The proposed hybrid antenna shows a measured return loss better than −20 dB in all the operating bands, a bidirectional radiation pattern and 4.8 dB gain in θ = 20◦ and 120◦ in E plane.

Flexible Antennas Based on Natural Rubber

Abstract: Flexible substrates have been increasingly studied in recent years. This paper proposes natural rubber as a new substrate material for flexible antennas. In our work, prototype antennas were built using rubber formulated with different filler contents. Carbon black was used as the filler where its amount was varied to yield different dielectric properties. Prototype inset-feed microstrip patch antennas with outer dimensions 7.52mm × 10.607mm × 1.7mm and copper as its conducting material were fabricated to operate at 2.45GHz. The prototypes were measured and their performance analyzed in terms of the effects of filler content on Q, return loss and bending effects on their gain and radiation characteristics. The return loss and gain were found to be comparable to those built on existing synthetic substrates, but these new antennas offer an added feature of frequency-tunability by varying the filler content. Under bending conditions, these new antennas were also found to perform better than existing designs, showing less changes in their gain, frequency shift and beamwidth, in addition to less impedance mismatch when bent.

Compact UWB Band-Notch MIMO Antenna with Embedded Antenna Element for Improved Band Notch Filtering

Abstract: A compact printed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with embedded structure is proposed. The proposed MIMO antenna consists of two coplanar waveguide-fed (CPW) antenna elements, and the element with smaller size is built in the radiator of the other element. Thus, the compact size, 30× 22 mm 2 , is completely determined by the larger one, which makes the MIMO antenna have similar size to the conventional single UWB antennas. The antenna elements are fed perpendicularly to achieve superior isolation. A T-shaped parasitic stub, a pair of C-shaped slots, an extended Z-shaped stub and a rectangular slot are employed and each two structures filter the interference for one antenna element. The achieved rejection bands remain relatively stable over the stop-band frequencies and decline rapidly at cut-off frequencies. Thus, the proposed MIMO antenna obtains superior filtering performance. The proposed antenna is fabricated and measured. The measured results indicate that two antenna elements can operate in the impedance bandwidth larger than 3.1-10.6 GHz with notched bands of 5-6 GHz, and the mutual coupling is below �15 dB over the entire UWB frequency spectrum. The proposed MIMO antenna is a competitive candidate for UWB MIMO communication systems.

Design of a Microstrip-Fed Hexagonal Shape UWB Antenna with Triple Notched Bands

Abstract: In this paper, a microstrip-fed hexagonal shape ultra-wideband (UWB) monopole antenna with triple notched bands is presented. The antenna consists of a microstrip feed line, a regular hexagonal shape radiation patch with a complementary split ring resonator (CSRR) and a pair of inverted T-shaped conductor-backed planes embedded in the antenna backside. Notched bands can be easily controlled by geometry parameters of the CSRR and conductor-backed planes. The simulated and measured results show that this monopole UWB antenna can offer an operation frequency from 2.93 GHz to 10.04 GHz with −10 dB return loss bandwidth, except three notched bands at 3.31-3.78 GHz, 5.33- 5.77 GHz and 7.24-7.72 GHz for rejecting the WiMAX and downlink of X-band satellite communication system signals. A good agreement between the measured and simulated results is observed. The proposed antenna provides broadband impedance matching, appropriate gain and stable radiation patterns over its operating bandwidth and can be used in wireless UWB applications.

Design of Flexible Passive Antenna Array on Kapton Substrate

Abstract: Recently, the RF/microwave electronic technology evolved with the consideration of plastic and organic substrates Such a technology offers two-folded benefits: in one side for lowering the fabrication cost and in another side for the possibility to bend electronic devices Such a technology is particularly interesting for the implementation of antenna system This paper is dealing with the design of flexible microstrip antenna 1:2 array Theoretical approach on the typically symmetrical antenna 1:2 array is proposed The design methodology of microstrip antenna combined with 1:2 T-power divider (T-PWD) is described Based on the transmission line theory, the S-parameter model of the antenna system with non-standard reference load is established Then, the microstrip antenna passive system is theoretical analysed in function of the physical dimensions of the designed structure The feasibility of the flexible antenna passive system is investigated with the proof-of-concept (POC) designed on Kapton substrate The POC prototype consisted of microstrip antenna 1:2 array is designed to operate at about 58 GHz Comparisons between the full wave simulated and measured return losses were performed Then, simulated radiation pattern highlights the efficiency of the fabricated prototype of passive antenna array

CPW and microstrip line-fed compact fractal antenna for UWB-RFID applications

Abstract: In this study, we present an implementation of Ultra Wide Band (UWB) Koch Snowflake antenna for Radio Frequency Identification (RFID) applications. The compact antenna, based on the Koch Snowflake shape, is fed by coplanar waveguide (CPW) and by microstrip line with an overall size of 31 × 27 × 1. 6m m 3 . The simulation analysis is performed by CST Microwave Studio and compared with HFSS software. The antenna design exhibits a very wide operating bandwidth of 13 GHz (3.4- 16.4 GHz) and 11 GHz (3.5-14.577 GHz) with return loss better than 10 dB for microstrip line antenna and CPW antenna respectively. A prototype of CPW and microstrip antenna was fabricated on an FR4 substrate and measured. Simulated and measured results are in close agreement. The small size of the antenna and the obtained results show that the proposed antenna is an excellent candidate for UWB-RFID localization system applications.

Shielding Effectiveness of Multiple-Shield Cables with Arbitrary Terminations via Transmission Line Analysis

Abstract: In this paper we report on a transmission-line model for calculating the shielding effectiveness of multiple-shield cables with arbitrary terminations. Since the shields are not perfect conductors and apertures in the shields permit external magnetic and electric fields to penetrate into the interior regions of the cable, we use this model to estimate the effects of the outer shield current and voltage (associated with the external excitation and boundary conditions associated with the external conductor) on the inner conductor current and voltage. It is commonly believed that increasing the number of shields of a cable will improve the shielding performance. However, this is not always the case, and a cable with multiple shields may perform similar to or in some cases worse than a cable with a single shield. We want to shed more light on these situations, which represent the main focus of this paper.

Design and Simulation of Fully Printable Conformal Antennas with BST/Polymer Composite Based Phase Shifters

Abstract: A fully printable and conformal antenna array on a flexible substrate with a new Left- Handed Transmission Line (LHTL) phase shifter based on a tunable Barium Strontium Titanate (BST)/polymer composite is proposed and computationally studied for radiation pattern correction and beam steering applications. First, the subject 1 × 4 rectangular patch antenna array is configured as a curved conformal antenna, with both convex and concave bending profiles, and the effects of bending on the performance are analyzed. The maximum gain of the simulated array is reduced from the flat case level by 34.4% and 34.5% for convex and concave bending, respectively. A phase compensation technique utilizing the LHTL phase shifters with a coplanar design is used to improve the degraded radiation patterns of the conformal antennas. Simulations indicate that the gain of the bent antenna array can be improved by 63.8% and 68% for convex and concave bending, respectively. For the beam steering application, the proposed phase shifters with a microstrip design are used to steer the radiation beam of the antenna array, in planar configuration, to both negative and positive scan angles, thus realizing a phased array antenna.

A Proximity-Fed Antenna for Dual-Band GPS Receiver

Abstract: A new design of dual-band L1/L2 GPS antenna is proposed. The antenna generates dual- band circularly polarized radiation by exciting a cross-slot and ring-slot of a concentric circular aperture using a proximity-coupled feed. Parametric studies show that the matching and axial ratio bandwidth of L1 (1.575 GHz) and L2 (1.227 GHz) bands can be independently tuned by alternating the ring radius and slot length. The range of frequency ratio and 3 dB center frequency can be highly adjusted by slot's parameters. The size of the antenna is 73 mm × 73 mm × 6.4 mm including the ground, corresponding to 0.29λ × 0.29λ × 0.026λ at 1.227 GHz.

Design of Multi-Beam Rhombus Fractal Array Antenna Using New Geometric Design Methodology

Abstract: Fractal array antenna design methodology is an artistic type of design methodology. Hence fractal array antennas are also called as artistic array antennas. This article proposes a concentric elliptical ring sub array generator geometric design methodology for a methodical expansion of multibeam fractal array antennas. Using this new geometric design methodology, any polygon shape can be constructed. This geometric design methodology provides a systematic approach for multiple beams of fractal array antennas, with unit amplitude constriction, using multi-beam sub arrays and without any increase in hardware complication. In this paper, a four-element rhombus fractal array antenna is examined using a proposed design methodology up to four concurrent iterations and for different eccentric values. Due to the recursive nature of the proposed methodology, the rhombus fractal array antenna shows multi-beam performance with abatement of beam width and better side-lobe levels. In the third and fourth iterations of the rhombus fractal array with expansion factor two, beamwidth reached single digit values of 7.2◦, 3.6◦ with side-lobe level angles of 15.5◦ and 8.1◦, respectively. The behavior of the proposed array shows better performance than four-element fractal array antenna generated by concentric circular subarray generator. The proposed fractal array antennas are analyzed and simulated by MATLAB programming.

Exploring Carbon Nanotubes/BaTiO3/Fe3O4 Nanocomposites as Microwave Absorbers

Abstract: This work was supported in part by FP7-PEOPLE-2013-IRSES-610875 NAmiceMC, FP7 Twinning Grant Inconet EaP 004. P. Kuzhir is thankful for support by Tomsk State University Competitiveness Improvement Program. Lab-STICC is UMR CNRS 6285.

Efficiency Enhancement of Wireless Power Transfer System Using MNZ Metamaterials

Abstract: In this paper, a simple approach for efficiency enhancement of a wireless power transfer system by using mu near zero (MNZ) type of metamaterial is proposed. A single slab containing onesided periodic structures of 3×3 array of meander-line unit cell has been placed between transmitting and receiving coils in the wireless power transfer system. The presented metamaterial structure is less complex than other reported metamaterial structures in the area of wireless power transfer system. The simulation and measurement have been performed with and without the metamaterial slab. Using the metamaterial slab, the maximum efficiency has been obtained about 55.3%, i.e., an improvement of efficiency around 15.7% is obtained compared to a wireless power transfer system without the metamaterials. Interestingly, the proposed wireless power transfer system shows a steady improvement of efficiency even if the distance between the transmitting and receiving coil is increased.

Beam-forming and beam-steering capabilities of a reconfigurable plasma antenna array

Abstract: We present the numerical parametric study of a reconfigurable plasma antenna array (PAA) composed of a metallic half-wavelength dipole and a set of cylindrical plasma discharges arranged in a planar square lattice. Our results, obtained with the linear embedding via Green’s operators (LEGO) method, indicate that beam-forming and beam-steering functionality can be achieved and controlled by appropriately choosing the number and position of the active plasma discharges around the dipole. Furthermore, we show that an external static magnetic field and the plasma density have a noticeable effect on the radiation pattern of the antenna.

Dual-chirp Arbitrary Microwave Waveform Generation by Using a Dual Parallel Mach-Zehnder Modulator Feeding with RF Chirp Signal

Abstract: In this paper, dual-chirped arbitrary microwave waveform has been generated through photonics, incorporated with single dual parallel mach-zehnder modulator (DPMZM) inbuilt mach zehnder interferometer (MZI) structure. We have taken two cases of chirping, i.e., linear and nonlinear chirps. A case of linear chirping has been explored previously. However, to the best of the authors' knowledge effect of nonlinear chirping in this paper is evaluated for the first time. Other photonics approaches are also available, such as spectra shaping and wavelength to time mapping. But due to fixed spectral response of spectral shaper, center frequency of linear chirp generated waveform is fixed. To get large center frequency again we have to use large number of spectral shapers which will increase the system complexity. DPMZM avoids such difficulties. These MZMs are biased at the minimum transmission point to get carrier suppressed modulation. Product modulator (PM) is cascaded to the lower arm of DPMZM. Here by using DPMZM we get two advantages. First we have two complimentarily chirped microwave waveforms and second up conversion of the frequency of microwave carrier. A dual-chirped microwave waveform with centre frequency 6 GHz with bandwidth 200 MHz and 2 GHz is generated. The paper gives specific details about various performance parameters such as input signal frequency and power, output signal parameters viz output frequency, chirp rate, chirp bandwidth, time bandwidth product (TBW), etc. The overall model and its performance parameters are computed through MATLAB simulation.