3D Radiation Pattern Research Articles

Bolometer tomography on Wendelstein 7-X for study of radiation asymmetry

The algorithm for bolometer tomography at Wendelstein 7-X (W7-X) has been recently improved using a novel regularization functional, based on relative gradient smoothing of the sought radiation profile. It has been validated using radiation patterns provided by 3D modeling under real plasma conditions as phantoms and then applied to bolometer measurements performed during the first divertor operation phase of W7-X. The following results are presented: (1) edge-localized 2D radiation patterns with clearly resolved magnetic island radiation structures, (2) an up-down asymmetry in the impurity radiation that is not captured by the 3D edge plasma transport modeling, (3) reversal of the asymmetry with reversed magnetic field direction. Further analysis reveals a poloidal variation of the emissivity in the outer confined plasma region with a field-direction dependent asymmetry, also supported by the soft x-ray measurements. This asymmetry is considered to be related to asymmetric impurity distributions, driven by the pronounced ion-impurity friction force at the plasma edge where the collisionality of the W7-X plasma is sufficiently high to develop impurity asymmetry as predicted by neoclassical theory of parallel impurity transport.

A Compact Dual Notch Frequency Reconfigurable Antenna for WIMAX,DSRC, RADAR and Ku band Communication Applications

A frequency reconfigurable ultra-wide band antenna with dual notch bands is proposed in this paper. PIN diodes are located on ultra-wide band monopole antenna and are investigated for frequency reconfigurable characteristic of the proposed antenna. Multi-bands and narrow bands have been achieved by different combinations. Proposed antenna is fabricated on FR-4 substrate of dimensions 37 x 40 x 0.8mm3. For the successful combinations, antenna performance parameters like S11 characteristics, surface current distribution, peak gain, radiation efficiency and 2D radiation patterns are analyzed and illustrated in the paper. Peak gain of 4.83dB is obtained in operating band for D1, D2= 0, 1 combination. Radiation efficiency is not less than 70% in the entire operating bands. Results are analyzed experimentally for validating proposed antenna. Simulation based results and measured results are in good agreement.

Special software application for antenna modelling in mechanical engineering

The article is devoted to one of the best today computer program for antenna modelling. No special computer simulation skills are required to use this software. In this study, based on foreign and domestic sources, the influence of the MMANA-GAL program on the design of various types of civil antennas is considered. The paper specifically describes this simulation program. The description includes its history of creation, application, comparison with previous programs and algorithms, the interface of the MMANA-GAL itself is also described. It tells about how useful this program is, how it simplifies life and saves time for developers and designers, since the built-in library contains examples of more than two hundred antennas. Standing out advantages are: its free-of-charge basis, and from the operational characteristics - display of 2D and 3D antenna radiation patterns and its frequency response.

An Inset-Feed On-Chip Frequency Reconfigurable Patch Antenna Design with High Tuning Efficiency and Compatible Radome Structure for Broadband Wireless Applications

A novel, dual edge-shaped frequency reconfigurable antenna with a highly compact size is proposed, using microstrip line-based inset-feed mechanism. The presented antenna uses cost-effective ROGER substrate with a thickness of 0.787 mm and has been studied for its gain and radiation pattern in the radome structure presence. The antenna resonates within the range of 3 GHz to 9 GHz approximately, with maximum tuning efficiency of 43 % at 6.5 GHz, covering the major wireless applications of aviation service and wireless local area network (WLAN) in the upper segment of S-band along with worldwide interoperability for microwave access (WiMAX), long-distance radio telecommunications, and X-band satellite communication. The proposed antenna works resourcefully with a reasonable gain of 2.3 dBi at 5.04 GHz, significant bandwidth of 2800 MHz (maximum at 6.5 GHz), directivity, and reflection coefficient. The proposed multiband reconfigurable antenna along with radome structure using ABS material has been investigated under high-frequency simulation environment of HPEEsof of ADS (by Keysight Technologies) and 3d radiation pattern (far-field gain, directivity and power calculations) have been obtained using momentum and EMDS simulators of ADS. The final implementation size (without radome structure) for the patch design comes out to be 23 mm X 26 mm large.

A New Beamforming Technique for the Synthesis of Uniform Circular Antenna Arrays Using Reduced Number of Antenna Elements

The number of elements reduction in different antenna array configurations such as linear, circular, rectangular, planar, and non-planar is of main concern for several research groups. This minimizes the complexity of the feeding network in static antenna arrays, whereas, in adaptive antenna arrays, it reduces the number of active components. The main issue in the array synthesis is to preserve the radiation pattern with minimum distortion compared to the original pattern. These issues are addressed by many researchers in linear, planar, and concentric circular arrays, but no attempt is made in the synthesis of uniform circular antenna arrays (UCAAs) that have elements distributed on a single circle. This is because the synthesis is almost performed in one plane where the radiation patterns in other planes are not predicted. In this paper, most of the aforementioned challenges are treated; the number of elements is reduced, the radiation pattern has minimum distortion, and the radiation pattern is symmetric in all array orthogonal planes. This is performed by dividing the original UCAA's 3D radiation pattern into a suitable number of 2D plane patterns, each of which is separately synthesized using the specified number of elements. The 2D pattern synthesis process for a particular plane is confined to estimating a new set of non-uniform excitation coefficients while keeping the original UCAA's array radius. To construct the final set of synthesized excitation coefficients for the 3D array pattern synthesis, we aggregate all of the estimated sets of excitation coefficients and take the average. To verify the efficacy of the proposed technique, the original and synthesized arrays are realized using the CST Microwave Studio using λ\mathord / \vphantom λ2 2 dipole elements. The results indicated that substantially matched patterns were obtained. Furthermore, the coupling between the synthesized array elements is decreased, which enhances the radiation efficiency and realized array gain.

Heptagonal Shaped UWB Antenna with DGS for Wireless LTE with Enhanced Bandwidth

The paper discusses about the implementation of Heptagonal shaped compact ultra-wideband planar Microstrip patch antenna with and without defected ground plane structure (DGS) with analysis of various parameters like return loss, VSWR bandwidth etc. A substrate made up of dielectric constant FR4 epoxy is utilized and the 2D and 3D radiation pattern are also discussed. DGS has helped to fine tune and increase the bandwidth & its effects have been studied. A volume of 28x32x1.7 (1523.2 mm^3) is occupied by the size of antenna with dielectric constant of εr = 4.4, tanδ= 0.02. In order to provide fine tuning in the return loss graph, a 50Ω line with width of W=3mm direct line feeding method has been used for the micro-strip line and slots have been introduced in the ground plane structure, for achieving the good bandwidth coupling between the slots plays an important role. The antenna parameters including VSWR, Gain and return losses v/s frequency effects for the antenna with variation of slots and dimensions has been studied in this paper along with the analysis of important parameters such as return loss (dB), bandwidth, VSWR (Voltage Standing Wave Ratio) of patch antenna which has been performed using Ansoft HFSS v15 tool. The proposed design of the heptagonal shaped antenna operates as an ultra-wide band antenna ranging from 3.20 GHz to 10 GHz and beyond covering most of applications from LTE, Wimax (3.5/5.55GHz), Radio altimeter, RFID and ISM WLAN 5.2/5.8GHz etc.

Coplanar waveguide fed compact dual-band antenna with capacitive shorting between signal strip and ground plane

A compact coplanar waveguide fed dual-band antenna using capacitive shorting between the signal strip and the ground plane is presented in this paper. The antenna achieves dual-band properties by making slots on the ground plane and capacitive shorting between the center feed and the ground plane through the slot. The proposed antenna occupies an area of 0.122λ01 × 0.134λ01 mm2 (λ01 is the free space wavelength of the first resonant frequency) and is printed on a substrate of relative permittivity 4.3 and thickness 1.6 mm. The experimental analysis shows a − 10 dB impedance bandwidth up to 6% and 30% for the first and second resonance bands respectively. The antenna radiation characteristics like reflection coefficient, 2D radiation pattern, gain and efficiency are measured and satisfy the requirements for ISM 5.2, ISM 5.8 and WLAN applications.

Throughput Performance Evaluation of LTE-Advanced with Inter-band Carrier Aggregation

The increasing number of mobile smartphone users requires additional spectrum to maintain cellular quality of service. The 800 MHz band is a good candidate to achieve this goal. It can be used as standalone spectrum or aggregated with other licensed bands to increase the available bandwidth. This paper compares through physical layer simulation the downlink throughput versus distance performance of LTE-Advanced in two different bands. We consider a high frequency band at 2.6 GHz and the 800 MHz to model bands 7 and 20 of inter-band carrier aggregation CA_7-20 respectively. The link level simulation is performed for single antenna system at three different urban locations. The channel is modelled using an enhanced 3D ITU-R channel model combined with measured 3D radiation patterns for the base station and user equipment antennas. The BER versus SNR results show that the 800 MHz band enjoys a gain of up to 1 dB as a result of higher Ricean K-factors. Moreover, for the assumed simulation parameters, at distances beyond 400 m the throughput of the 800 MHz band is significantly higher than the 2.6 GHz band. At a distance of 750 m, the throughput for the 800 MHz band is 4.5 times greater than the 2.6 GHz band. These benefits are shown to relate to the lower path loss values observed in the 800 MHz band.

An Antenna Characterization Demo System Using an RFID Hemispherical Dome [Education Corner

Antenna measurement is crucial for characterizing the performance of an antenna. This article proposes a measurement technique that can be used for demo purposes in a class or laboratory for characterizing ultrahigh frequency (UHF) antennas. This approach measures the antenna under test (AUT) semispherical pattern simultaneously without any mechanical rotation as commonly applied. The measured data are then processed using a laptop connected to a radio-frequency identification (RFID) reader (transceiver) to identify various antenna properties. The setup limitations, considerations, and measurement demonstration are presented in detail. The system was successful in characterizing several antenna properties, including antenna polarization, frequency of operation, and efficiency, as well as constructing a 2D and full 3D radiation pattern for different test antennas. The in-class measurements were verified with simulations and anechoic chamber measurement data.

Design of Multiband Frequency Reconfigurable Antenna with Defected Ground Structure for Wireless Applications

A novel printed rectangular shape, multi-band frequency reconfigurable antenna with defected ground structure (FRDGS) for multi standard wireless communication systems is designed in this article. The ground plane is modified by embedding U shaped slots with open ends and I shaped slot in short ends to realize the multi band frequency of the antenna and to improve the parameters of the antenna design. The two U shape slots are etched symmetrical to each other to reduce the cross polarization of the antenna. The DGS in the ground plane altered the modeling characteristics of transmission lines with the equivalent values of inductance, capacitance and resistance. Three PIN diodes are inserted in the ground plane to acquire the switching characteristics of multi-resonance frequency. Simulated and measured output clearly depict that the antenna proposed is efficient to change between twelve dissimilar resonant frequency bands centered at 1.36, 1.8, 3.0, 3.9, 5.0, 6.2, 6.4, 7.4, 7.9, 8.2, 8.4, 8.6 GHz through different states of modes over the frequency spectrum from 1.33 to 8.7 GHz. The parameters such as reflection coefficient, VSWR, 2D and 3D radiation pattern, bandwidth, peak gain, peak directivity, gain and directivity are simulated using Ansoft HFSS 17.0v. The proposed antenna finds application in various wireless communication system such as Wi-Fi (5 GHz), WLAN (5 GHz), WI-MAX, UWB (3.1–10.6 GHz) system, fixed mobile and satellite communication systems.

Compact and flexible meander antenna for Surface Acoustic Wave sensors

This paper presents an innovative, flexible and biocompatible Ultra High Frequency meander antenna, operating at about 800 MHz, realized by means of sputtering on a Polyethylene Naphthalate substrate, and by means of a multi-material 3D printer. The fabricated antennas were characterized in terms of scattering parameters, showing a good impedance matching and a bandwidth in the order of tens of megahertz, gain and 3D radiation patterns. A numerical model was also introduced to investigate the limits of the proposed technologies in terms of metal thicknesses. The fabricated antenna could be efficiently integrated with Surface Acoustic Wave resonators to realize compact, wireless, wearable and battery-less sensing platforms.

Generation of Plane Spiral Orbital Angular Momentum Waves by Microstrip Yagi Antenna Array

Compared with the orbital angular momentum (OAM) wave whose 3D radiation pattern is a central-hollowed cone, the plane spiral orbital angular momentum (PSOAM) wave propagates along the transverse direction, which is far more convenient for practical applications. In this paper, traditional microstrip Yagi antennas are formed into a uniform circular array (UCA) to radiate PSOAM electromagnetic waves, which has the outstanding advantage of a flat structure. Firstly, the fundamentals of generating PSOAM by microstrip Yagi antenna array is introduced. Secondly, a circular microstrip Yagi PSOAM antenna array fed by a self-designed Wilkinson feeding network is designed, fabricated and measured. Eight microstrip Yagi antenna elements and its feeding network are printed on the upper and lower substrate, respectively. The profile of the proposed antenna is only $0.16\lambda _{0} $ , lower than other PSOAM antennas, which is convenient for integration with wireless communication systems. Both simulation and measurement results depict that it is capable of generating PSOAM with mode number $l=3$ on 3.43GHz. From 3.15GHZ to 3.65GHZ, the vortex electromagnetic wave of $l=3$ can be observed. The proposed microstrip Yagi antenna based on UCA provides a new way for the research of practical PSOAM antennas, has broad prospect in the future of the reconfigurable field.

Coaxial Probe Fed Modified Sierpinski Fractal Antenna for Wireless Applications

A modified Sierpinski fractal antenna has been designed for wireless applications. The designed antenna exhibits multiple resonance behavior due to the basic attributes of the fractal shapes. The proposed antenna has planar, compact in size and is suitable for various wireless applications. It is designed on the Flame Retardant epoxy board substrate (FR4), which is very easily available, light in weight and has less cost. IFS (Iterated Function System) methodology is accustomed to generate the complex fractal layout using the scripting methodology (.vbs) in the HFSS simulator. Scripting method provides a straight forward solution to generate complicated fractal structures by generating code in MATLAB. The proposed antenna resonates at five different frequencies 1.859 GHz, 3.623 GHz, 5.929 GHz, 9.095 GHz and 9.547 GHz with smart values of return loss up to - 26 dB. It additionally demonstrates good radiation properties and has VSWR values less than two for all resonating frequencies. Radiation characteristics are displayed by 2D and 3D radiation patterns. It also has an low profile value of Gain of 3 dB.

Low-Cost Transmitarray Antenna Designs in V-Band based on Unit-Cells with 1 Bit Phase Resolution

Abstract This paper presents the design and characterization of linearly polarized low-cost transmitarray antennas with ± 70° azimuth beamforming range in V-band in order to add beam steering functionality to existing radar front ends. The transmitarray antennas are composed of 13 × 13 planar unit-cells. The unit-cells consist of two layers of RO4350B laminate and provide a one bit phase resolution. The desired unit-cell behavior has been validated by simulations and measurements. Eight transmitarrays with different phase distributions have been designed and fabricated to realize different beam steering angles in azimuth. The experimental characterization of the radiation patterns shows the desired performance in the frequency range from 59 GHz to 63 GHz. Additionally, steering angle combinations in azimuth and elevation up to 40° have been realized and successfully demonstrate by measuring the 2D radiation pattern.

Miniaturised MIMO antenna array of two vertical monopoles embedded inside a planar decoupling network for the 2.4 GHz ISM band

This study introduces a fundamentally new approach to suppress mutual coupling among two closely-spaced vertical monopole elements of a multiple-input multiple-output antenna array. The 40 × 40 × 1.27 mm decoupling and matching element consists of a single planar ring resonator acting as a stop-band filter along with two tuning strips printed on an ungrounded substrate surrounding a two-element co-planar waveguide-fed monopoles separated by 8 mm ( λ 0 /16) at 2.45 GHz. Measurements reveal 14.2% bandwidth centred at 2.395 GHz over which the decoupling is below 20 dB, and -10-dB impedance bandwidth of 19.5% centred at 2.36 GHz. An improvement of 43 dB in isolation is observed at a frequency of 2.38 GHz. It is shown that the decoupled array provides a total realised gain of 1.69 dBi with excellent diversity performance as demonstrated by the low envelope correlation coefficient and improved link efficiency in highly-correlated channel environments due to the spatially orthogonal 3D radiation patterns. The capacity offered by the decoupled array is enhanced by 50, 22, 18 and 12% at signal-to-noise ratios of 5, 20, 30, and 50 dB, respectively, as compared to the coupled array in an urban micro-channel spatial model.

3D Multi-Beam and Null Synthesis by Phase-Only Control for 5G Antenna Arrays

This paper presents an iterative algorithm for the synthesis of the three-dimensional (3D) radiation pattern generated by an antenna array of arbitrary geometry. The algorithm is conceived to operate in fifth-generation (5G) millimeter-wave scenarios, thus enabling the support of multi-user mobile streaming and massive peer-to-peer communications, which require the possibility to synthesize 3D patterns with wide null regions and multiple main beams. Moreover, the proposed solution adopts a phase-only control approach to reduce the complexity of the feeding network and is characterized by a low computational cost, thanks to the closed-form expressions derived to estimate the phase of each element at the generic iteration. These expressions are obtained from the minimization of a weighted cost function that includes all the necessary constraints. To finally check its versatility in a 5G environment, the developed method is validated by numerical examples involving planar and conformal arrays, considering desired patterns with different numbers of main beams and nulls.

Azimuth Angle Estimation for a Reduced Radiation Region Formed by a Metaspiral Antenna

A two-arm metaspiral antenna is presented, where the feeding voltage sources are expressed using excitation amplitude r and deviation angle δ. This excitation is decomposed into the odd mode and even mode components. The odd mode component forms a circularly polarized (CP) axial beam and the even mode component forms a CP conical beam, whose maximum intensity is off the antenna axis. Superimposing the conical beam onto the axial beam forms a reduced radiation region in the elevation plane. The reduced radiation region is used for minimizing transmission in a particular φ FBD direction or the rejection of interference signals from the φ FBD direction. This paper presents a formula that estimates the azimuth angle of the reduced radiation region. The formula features the excitation mode ratio, m, and the mode phase difference, ΔΦ. The formulated azimuth angle is validated by showing good agreement with the simulated azimuth angle obtained by searching for a null over the 3D radiation pattern. The formula is simple and hence supersedes the time-consuming 3D null search.

3D Radiation Pattern Reconfigurable Phased Array for Transmission Angle Sensing in 5G Mobile Communication.

This paper proposes a 3D radiation pattern reconfigurable antenna (RPRA) and a reconfigurable phased array (RPA) for 5G mobile communication. The antenna and array are working at 28 GHz, which is selected as a 5G communication band in many countries. The proposed phased array will be applied as sensors to find out the optimal transmitting–receiving angle in a randomly changed cellular wireless scenarios. The RPRA and RPA are fed by Substrate Integrated Waveguide (SIW) and have three switchable radiation modes: Broadside 1, Broadside 2 and Endfire. The three modes correspond to three different radiation patterns and each of them covers a different area in the Azimuth plane. An eight-element phased array constructed by the proposed RPRA, which is able to switch beam in Azimuth plane and scan in the Elevation plane, is also presented in this paper. The proposed RPA is able to provide much higher spatial coverage than the conventional phased arrays and without additional feeding and phase shifting networks. The beam switching is realized by the PIN diodes. The proposed antenna and array have planer structures and require small clearance on the ground plane which makes them compatible with mobile phones. The simulations show good performance for both RPRA and RPA.

On development of a MIMO antenna for coupling reduction and WiMAX suppression purposes

A multiple-input multiple-output (MIMO) WiMAX band-notched antenna with reduced mutual coupling is proposed for ultra-wideband (UWB) applications. The proposed MIMO structure consists of two square monopole antennas with two modified L-shaped slots, a rectangular ground plane structure, and a rectangular parasitic structure for increased isolation. Simulation and measurement studies are used to probe the antenna performance in terms of s-parameters, isolation between the two input ports (S21), antenna gain, group delay, ECC, 2D and 3D radiation pattern. Results show a bandwidth with |S11|, |S22| ≤ −10 dB, |S21| ≤ −20 dB, and frequency ranged from 2.8 to 10.9 GHz excluding a rejected band from 3.4 to 3.9 GHz, focusing on WiMAX frequency band. The MIMO antenna prototype with a compact size of 18 × 36 mm2 is fabricated and measured. Based on the obtained experimental results, the proposed MIMO antenna could be regarded as a good candidate for UWB MIMO antenna with band-notch characteristics.

Design of CPW antenna for network applications

The novel CPW antenna design consists of monopole, which can used for High speed wide area or local area corporate networks and Video & CCTV surveillance networks and Long-range Rural connectivity. This antenna has been designed with design size parameters of 59.5(L) x 30 (W) x 1.6-(H) mm2, the dielectric constant of FR4 substrate is 4.4, and loss tangent of 0.002 is used. The resonant frequency range of this proposed antenna is 5.85 - 6.6 GHz with return loss above of -10dB achieved. The peak gain of this antenna is 5.5dBi and in addition the S, Z-parameters, VSWR, 2D & 3D radiation pattern are also derived. Good results are achieved after simulation.