Isolation enhancement of metamaterial structure MIMO antenna for WiMAX/WLAN/ITU band applications

The μ-negative metamaterial (MNG) two-element MIMO antenna design was proposed in this article for WiMAX (2.5–2.8 GHz), WLAN (3.2–5.9 GHz), and ITU band (8.15−8.25 GHz) applications. The first design of the MIMO antenna operates at 2.7 and 4.9 GHz frequencies. In order to reduce the mutual coupling, a defective ground structure is used. For further isolation improvement, an MNG unit cell is placed in between the two radiating elements at a distance of 10 mm. The designed antenna elements have better than −23 dB coupling isolation between the two radiating elements. Moreover, with MNG an additional frequency of 8.2 GHz is obtained, which is useful for ITU band applications. The proposed antenna bandwidth is expanded by 19% in the lower operational band, 20% in the second operational band, and 32% in the higher frequency band with the MNG unit cell. From the analysis, the proposed antenna is suitable for WiMAX/WLAN/ITU band applications because of its low enveloped correlation coefficient, and highest directive gain and low mutual coupling between the radiating components. The proposed antenna was simulated, fabricated, and measured with the help of the Schwarz ZVL vector network analyzer and anechoic chamber. Both measured and simulated results are highly accurate and highly recommended for WiMAX/WLAN/ITU bands.

Circular Polarization Array Antenna with Triplate Stripline Elliptic Resonator Antennas

This paper presents a plane antenna and array for X-band circular polarization. The novel factors of this development are elliptic resonator antenna and Glass-Epoxy substrates. High efficiency in resonance and radiation of microwave energy is expected by elliptic resonators. Easy process in fabrication is expected by Glass-Epoxy substrate. Elliptic ratios of feed- and reactance-elements are chosen independently each other. The dielectric constant εr and tan δ are 4.6 and 0.010 respectively. Enough bandwidth of axial ratio of circular polarization and directive gain are confirmed to be 15 % of central frequency and 10 dB respectively for antenna array.

Directional radiation properties of two impedance monopoles mounted on a perfectly conducting rectangular screen

Subject and Purpose. Two impedance resonant monopoles of electric length 0.2 £ l / l £ 0.3 are mounted on a rectangular screen perpendicularly to the screen surface and studied for the directional radiation properties (directive gain and radiation patterns) depending on the monopole separation and the side length and aspect ratio of the screen. Methods and Methodology. A three-dimensional diffraction vector problem of two impedance monopoles mounted on a perfectly conducting rectangular screen is solved in terms of the uniform geometric theory of diffraction. Allowances are made for the diffracted field asymptotics of the secondary diffraction at the screen edges and for the electric current distribution asymptotics of a thin impedance dipole in the free space. Results. For a lattice of two impedance monopoles mounted on a rectangular screen, 3-D programs have been developed for calculating its radiation patterns, directive gain Dmax at a radiation maximum, and radiation resistance in view of the secondary diffraction at the screen edges. The radiation pattern shaping for the diffraction and total fields and the directive gain Dmax have been analyzed depending on the monopole separation x / l  0.1...1, the screen side length x / l  1.2…4, and the screen aspect ratio W / L  0.5…3. It has been shown that the so obtained optimum separation x opt  0.65, optimum length Lopt and optimum ratio (W / L) opt make Dopt three times greater than the lowest Dmax value. Conclusions. The three-dimensional vector problem of field diffraction of two impedance monopoles mounted on an ideally conducting rectangular screen has been solved. It is of interest that given an optimum monopole separation xopt and an optimum side length Lopt of the square screen, a lattice of two monopoles offers a greater radiation resistance and a two times larger Dopt than a single monopole on the same screen does. The developed computational programs and the obtained numerical results enable efficient actual wireless communication systems to be modelled for both ideally conducting and impedance resonant monopoles.

Investigation of energy stealth of radar stations with band antennas from the radio monitoring complex

Using spectral representation of non-harmonic processes and partial characteristics of antennas, energy equations of transmissionreception of broadband signals in the radio channel with scattering on the object and the direct radio channel between the radar and the radio monitoring (RM) complex have been obtained. Energy of received signals is determined by value of product of spectral density of radiation power and partial moment of transmission-reception averaged in the range of cyclic frequencies. The signal-to-noise ratio at the receiver input reaches the highest value when the partial moment of transmission-reception of signals in the radio channel changes according to a linear law. At fixed average radar power, energy of information signals at incoherent accumulation can be increased due to selection of antennas with partial directive gain amplifying wave processes in areas of their spectra concentration. The range of the radar is proportional to the linear dimensions and significantly depends on the shape of the object. The rules of antenna characteristics selection are justified to ensure radar stealth from RM systems while maintaining the required range of target detection and recognition. When using an antenna with a partial directive gain constant in the range of working cyclic frequencies in the radar, and in the RM complex of an antenna system with a frequency-independent effective area, the partial moment of transmission-reception of signals in the forward radio channel is constant. Its value is determined by the product of partial directive gain at the central frequency of the range. Forms of pulses supplied to input of transmitting antenna and radiated into space coincide, and shape of signal at output of receiving antenna has the form of their derivative. Due to application of frequency-independent antennas in radar and RM complex, energy of probing signals increases compared to levels typical for antenna systems with partial directivity indices varying in proportion to current value of cyclic frequency in the first or second degree. This pattern is due to the significant effective area of the receiving antenna in the lower part of the frequency range, which parries the low efficiency of radiation of low-frequency components of the radar signal spectrum. In radio channels with partial moments of transmission-reception of signals varying with frequency increase according to linear law, energy supplied to receiver input increases in comparison with levels achievable at quadratic and cubic dependencies of partial moments on cyclic frequency due to the same type dependencies of partial directive gain antenna of radar and effective area of antenna of RM complex. Stealth of probing radiation increases as dimensions of radar antennas increase due to increase of partial directive gain and decreases as dimensions of antenna systems of RM complexes increase due to increase of their effective areas. The duty cycle of pulses forming regular sequences, established due to the condition of accumulation of energy of reflected signals due to irradiation of the object, which is required to complete the functional tasks of the radar, decreases in proportion to the increase of the partial directive gain antenna at the central cyclic frequency. Energy of information signals increases in proportion to coefficients depending on relative half-width of their spectra, and decreases with increase of central cyclic frequency to the second degree. As pulse repetition frequency increases at maximum permissible average density of radiation power limited by radar stealth requirements, energy density of probing signals decreases proportionally. The average power of the radar at a fixed level of spectral density varies in proportion to the bandwidth occupied by the probing signals due to a reduction in the following period.

Design and Simulation of Slot Dimensions in Aperture Coupled Hemispherical Dielectric Resonator Antenna

Aperture coupled novel shaped Hemispherical Dielectric Resonator Antenna (HDRA ) and the various dimensions of slots are designed and analyzed by hfss software. The dielectric constant of dielectric hemisphere is € =9.8 and the substrate of dielectric constant is 2.96. aperture coupled novel shaped Hemispherical Dielectric Resonator Antenna (HDRA ) parameters are presented in this paper.. The effects of changing the slot length , slot width and position of slot on the antenna parameters and are presented in this paper, which are used for directive gain applications. As the change of slot dimension , it is observed that at the resonant frequency, it gives high gain and high negative return loss

High Isolation Superwideband Monopole Antenna with Mitigation of Dual Interfering Bands (WiMAX/C and Satellite Communication System in X Band) for Wireless Applications

In this manuscript, a dual notched superwideband Multiple-Input-Multiple-Output (MIMO) monopole antenna is verified in frequency, time and spatial domain. Antenna occupies space of 18340.787 mm3 and is printed on (Rogers RT Duroid5880) microwave substrate. Proposed antenna is capable of covering bandwidth 2.66 GHz–22.31 GHz with bandwidth ratio > 10:1. Proposed antenna rejects WiMAX/C band (3.28 GHz–4.36 GHz) which is obtained by using L-shaped stub connected with ground and X-band satellite downlink/uplink interference is removed by etching inverted U-shaped slit in microstrip feedline. Also, antenna offers maximum gain of and radiation efficiency of 5.30 dBi and 96.20% respectively in operating band. Proposed antenna also shows good diversity performance in terms of ECC (Envelope Correlation Coefficient), DG (Directive Gain) and TARC (Total Active Reflection Coefficient).

Engineering Technologies Microstrip Patch Antenna Radiation Variation of Quality Factors and Bandwidth of a Conically Depressed

In connection with the development of radio communication systems, microwave, millimeter range, one of the most important is the problem of creating compact solid-state radiation sources. The antenna is the effective interaction between electronic circuits and the outside world is an important component of any wireless connection trend toward line the use of high frequencies in modern communications. Solutions, space technology, about (30 Ghz), Local Multipoint Distribution (LMDS) at 28Ghz) antenna technologies to meet the new requirements of the card actively participated in the elaboration of the various subsystems for such active monolithic Phased Array Antenna. This document is primarily.This paper mainly studies the effect of plasma wave on the radiation properties of a conically depressed microstrip patch antenna. Using linearized hydrodynamic theory and potential function technique, the total directive gain and quality factor are calculated for different values of plasma to source frequency and different half-cone angles. It is observed that the directive gain and quality factor are changes considerably by changing the half-cone angle as well as a plasma to source frequency values. © 2018 JASET, International Scholars and Researchers Association. Author Biographies Ayman Al-Sawalha Physics Department, Faculty of Science, Jerash University, Jerash , Jordan Takialddin Al Smadi Department of Communications and Electronics Engineering, College of Engineering, Jerash University, Jordan.