Sheikh Sharif Iqbal

An 800 MHz 2

A compact size 2 × 1 multiple-input-multiple-output (MIMO) antenna system operating in the 800 MHz band is proposed for long term evolution (LTE) handsets. The fabricated MIMO system has a typical isolation of 12 dB and a maximum gain of 2.2 dBi. Two isolation enhancement methods are investigated; one that looks into the depth of the ground split separating the two antennas, the other introduces extra splits within the arms of the GND plane. It is found that introducing extra splits within the arms of the GND plane of the proposed geometry enhances the isolation by at least 3 dB. The proposed MIMO antenna system is based on meander line antennas, and covers the band from 760-886 MHz. The size of the antenna system is 40 × 50 mm2.

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Fourth generation mobile networks (also called Long Term Evolution — LTE) will make use of multiple-input-multiple-output (MIMO) technology to achieve very high data rates in both the uplink and downlink. MIMO is based on the use of multiple antenna systems within the mobile terminal as well as the base station. The small size of the mobile terminal poses series integration and antenna miniaturization challenges. In this work, we propose an electrically small antenna (ESA) that is based on the meander antenna structure that operates in the 800 MHz band of LTE and 3G cellular standards. The antenna has a measured center frequency of 897 MHz, bandwidth of 185 MHz and total size of 23.5 × 43 mm2. Both simulation and experiment results are presented. A study on the effect of the various antenna parameters that will aid the designer fine tune his structure is also discussed.

1 Compact MIMO Antenna System for LTE Handsets

Performance of a novel integratable broadband antenna employing inverted microstrip circular patch (IMCP) is presented based on the simulation and experimental studies. The antenna geometry embodies dual stacked patches printed back to back on a single substrate in an inverted microstrip configuration. Unlike previous designs, the present stacked patch offers easy integration of active devices with large bandwidth without any enhancement in weight, volume or cost. The design is built up in steps through optimizing the antenna parameters using an HFSS full wave solver and the steps are verified experimentally, showing close agreement between them. Nearly 15% SWR < 2 bandwidth has been reported. Over 90% radiation efficiency with 7 dBi gain is evident from the simulation data. Principal plane radiation patterns are examined using numerical and experimental data, revealing its suitability for mobile communication equipment.

Design of anelectrically small meander antenna for LTE mobile terminals in the 800 MHz band

A simple design of a compact probe-fed stacked patch antenna is proposed for broadband applications. The antenna design is presented on the basis of simulation results. The possibility of achieving as much as 24% impedance bandwidth (SWR<2) from a compact antenna is revealed.

Performance of Compact Integratable Broadband Microstrip Antenna

A novel beam scanning technique of a ferrite loaded microstrip patch antenna is presented. Beam scanning is produced from controlled interaction of the radiated fields and the gyromagentic properties of the axially magnetized ferrite rods. By varying the magnetizing fields of the ferrite rods, optimally placed in the near field region of the antenna, necessary phase taper of the radiated E-field distribution is achieved. The designed 10 GHz antenna demonstrated an impedance bandwidth of 700 MHz and ±30° of beam scan for a changing magnetizing field of 170 kA/m. Employing embedded biasing coils through LTCC technology, the required biasing fields needed to achieve beam scan can be considerably reduced.

Simple design of a compact broadband microstrip antenna for mobile communication

Abstract An exact closed-form technique is employed to calculate the cutoff wavenumbers of a conducting circular waveguide loaded with two circular dielectric cylinders. An analytical expression of the hybrid modes is derived in terms of cylindrical coordinates of the geometry. The addition theorem of Bessel functions is used to transfer the electromagnetic fields from one coordinate system to another to apply the boundary conditions. A MATLAB (The MathWorks, Natick, Massachusetts, USA) code is developed to solve the system of equations and produce the cutoff wavenumbers for different geometrical parameters. The present problem can be extended to model a circular waveguide loaded with multiple dielectric cylinders that resembles a petroleum-carrying pipeline. A professional High Frequency Structure Simulator (HFSS; ANSYS, Inc., Canonsburg, PA, USA) is used to solve this model and to determine the ratio of the multi-phase fluid.

Beam scannable microstrip patch antenna

Technological development has driven electronic component design into the miniature world resulting in surprisingly small yet shockingly powerful devices. In an attempt to decrease the size of handheld wireless communication devices, it is necessary to design the smallest possible antenna structures that fulfill the communication needs. In this paper we present the design and analysis of a 7-patch antenna array operating at 10 GHz with shorting posts that tend to decrease the size by more than 50% as compared to the original. In addition we have succeeded in getting a directivity boost of 3 dB by using Fabry-Perot (FP) cavity utilizing frequency selective surfaces (FSS). Design and analysis of the antenna array as well as the FSS layer is presented in this work. Simulation results clearly indicate the advantages of this design in terms of smaller size and higher directivity.

Cutoff Properties of a Circular Waveguide Loaded with Two Eccentric Dielectric Cylinders

Switchable magnetic media and shorting posts are popular in controlling both the radiation characteristics and size of microstrip patch antennas. In this paper, a ferrite-based shorted circular patch antenna is designed to demonstrate magnetically switchable dual frequency response. The DC magnetic bias, applied normally to the ferrite substrate, allowed the antenna size to be reduced by as much as 80%. Optimized length and position of the reactive post exhibited improved impedance bandwidth with excellent frequency tuning capabilities. Commercial software is used to simulate resonance and radiation responses of the designed antenna.

Design of a reduced size 7-patch antenna array with FSS based directivity enhancement

Magnetized ferrite resonators have so far been used to produce tunable microwave filters and junction circulators up to around 40 GHz. Above this frequency range, the nonreciprocal behavior of commercial ferrite decreases with increasing losses, whereas the losses in magnetized semiconductors become more acceptable. In this article, the gyrotropic characteristics of magnetized semiconductor disk resonators are investigated using applied field/frequency parameters. The nonlinear relationship between the existing tensor entry description and the field/frequency solution is established. The sensitivity of the resonant frequency to geometrical and material properties of the semiconductor disk is observed and tabulated. Finally, the S-parameters of a magnetized two-port semiconductor network are derived at microwave and millimeter-wave frequencies. The aim of this work is to provide simulated results for calibrating the semiconductor resonator, essential for conducting successful experiments on semiconductor junction devices.