Helical Antenna Research Papers - Academia.edu (original) (raw)

-In our work reported, the focus is around miniaturization and reconfigurability of antennas. Our topic “Reconfigurable Antenna for 4G LTE and 5G Applications” is reconfigured form of previous antennas and it deals with 5 or more bands of... more

-In our work reported, the focus is around miniaturization and reconfigurability of antennas. Our topic “Reconfigurable Antenna for 4G LTE and 5G Applications” is reconfigured form of previous antennas and it deals with 5 or more bands of LTE [2140MHz, 4200MHz, 5650MHz, 5900MHz and 12.04GHz]. It provides wide range of applications for modern communication systems. It is efficient and there are no mobility issues in it as were in previous antennas. It is an important feature of RF systems. With it a single device can access more than one wireless standard. The Re-configurability can be obtained by changing frequency, polarization, radiations pattern and their combination. Pin diode are used, to achieve reconfigurability. We prefer pin diode (MPP4203) for reconfigurability, due to its high resolution, high switching speed, reliability, and compact size, also it’s a very high attenuator. We worked on HFSS [8] and CST [9] for modelling of this antenna. Reconfigurable Antenna is working on maximum bands of LTE and so it can facilitate more services and users.

The growth of smart antennas replaced many older technologies. Likewise, this paper presents a study on design of monopole antenna array with multiband multiple-input–multiple-output (MIMO) antenna system for small mobile terminals. Many... more

The growth of smart antennas replaced many older technologies. Likewise, this paper presents a study on design of monopole antenna array with multiband multiple-input–multiple-output (MIMO) antenna system for small mobile terminals. Many smart antennas are designed with variable sizes for many different types of uses. In those, each antenna will support particular range of frequency, and some antennas may support few range of frequencies. But the antenna design which is presented in this paper supports five different frequencies. Those are 900, 1800, 2100, 3500, and 5400 MHz, which means, the antenna designed supports five resonant modes. This antenna covers GSM850/900, DCS, PCS, UMTS, WLAN and WiMAX frequency bands.In case of proposed system, a small and compact triple-band microstrip-fed printed monopole antenna for WLAN and WiMAX will be used. The proposed antenna will have a rectangular radiating patch with “L” and “U” shaped slots and ground plane. The proposed antenna is expected to be small when compared to antenna design discussed in this paper. The proposed paper presents a study on a small and compact triple-band microstrip-fed printed monopole antenna for Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX). The antenna designed in this paper consists of a rectangular radiating patch L- and U-shaped slots. The length of the L and U shaped slots are designed to obtain the required frequency bands—namely, WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5 GHz).

Bistability in doubly curved and twisted (helical) composite slit tubes is investigated for the first time. This work establishes a natural extension in this area which has been focused on straight and until more recently, doubly curved... more

Bistability in doubly curved and twisted (helical) composite slit tubes is investigated for the first time. This work establishes a natural extension in this area which has been focused on straight and until more recently, doubly curved (toroidal) tubes with positive Gaussian curvature. The model developed introduces longitudinal and transverse curvature, and twist into strips of laminated composite material. The composite is engineered to be bistable and the second stable state determined via strain energy minimisation using the Rayleigh-Ritz method. The strain energy is formulated as a function of curvature strains, longitudinal stretching and a variable middle ply fibre angle of the laminate. The second stable state forms a compact and untwisted cylindrical coil with the latter engineered by tailoring the middle ply fibre angle. A new manufacturing process capable of producing helically curved tubes using glass-fibre/polypropylene-matrix composite is presented to verify the hypothesis of this work. An untwisted coil enables the efficient stowage and deployment of new forms of bistable composite tube which adhere to similar form factors as straight and toroidal ones. By embedding electrical conductors, helical bistable composites enable new lightweight, compact and multifunctional structures for communication and sensing applications.

Introduction: The quadrifilar helix antenna (QHA) is used widely for terrestrial [1] and space communication systems [2], where it is necessary to generate a circularly polarised cardioid-shaped radiation pattern with a high front-to-back... more

Introduction: The quadrifilar helix antenna (QHA) is used widely for terrestrial [1] and space communication systems [2], where it is necessary to generate a circularly polarised cardioid-shaped radiation pattern with a high front-to-back ratio and low cross-polarisation. The radiating structure comprises four helical conductors which are excited in phase quadrature at the feed point, which is usually located at the centre of the top radials. The physical size of the quadrifilar antenna can be reduced by dielectric loading [3] or by meandering the printed linear elements [4]. However, in the former arrangement dielectric absorption reduces the radiation efficiency of the antenna, and the latter technique is not suitable for constructing free standing wire structures, which are normally used for spacecraft payloads in the VHF and UHF bands [2]. This Letter shows that a significant reduction in the axial length of a 1/2 turn half-wavelength QHA can be achieved by modifying the geometr...

... Quadrifilar Helix Antenna With Dual Mode Operation Muhammad Amin, Robert Cahill, and Vincent F. Fusco, Fellow, IEEE Abstract—We show that by introducing a gap at the center of the helical sections (where the current is minimum) of a 2... more

... Quadrifilar Helix Antenna With Dual Mode Operation Muhammad Amin, Robert Cahill, and Vincent F. Fusco, Fellow, IEEE Abstract—We show that by introducing a gap at the center of the helical sections (where the current is minimum) of a 2 quadri-...

In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell covered by a base transceiver station (BTS) mounted on high altitude platform (HAP) at the sfratosphere layer. To this end, an ideal cosine shape... more

In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell covered by a base transceiver station (BTS) mounted on high altitude platform (HAP) at the sfratosphere layer. To this end, an ideal cosine shape radiation pattern raised to the power of N is applied to select the appropriate antenna for achieving the optimum coverage. The optimum selection is based on minimizing the blind area, having less overlapped to total area ratio, and increasing the total coverage area, simultaneously. Our proposed scheme has two degrees of freedom; first, the values of N determining the directivity and half power beam width (HPBW), and second the angle a denoting to the mechanical tilt of the antenna elements. To find the optimum pair of (N, a), several simulations are done and the corresponding footprint contours are depicted. Simulation results show that utilizing three ideal cosine function antennas with N = 9 installed by a = 38 degrees of mechanical tilt with respect to the normal is optimum for a macro cell coverage in an urban area by using HAPs located at 17 km altitude. Index Terms-BTS anterma, GSM, and high altitude platforms.

A side-fed bifilar is shown to generate a similar radiation pattern as a dipole antenna, but the structure has a significantly reduced axial length. Simulated and measured results show that the helix turn angle can be used to control the... more

A side-fed bifilar is shown to generate a similar radiation pattern as a dipole antenna, but the structure has a significantly reduced axial length. Simulated and measured results show that the helix turn angle can be used to control the ratio of the orthogonal linear field components and the input impedance.

I. INTRODUCTION QUADRIFILAR helix antennas (QHAs) are often used to provide the broad beam circularly polarized patterns which are required for satellite communications [1]. The QHA consists of four helical conductors which are excited in... more

I. INTRODUCTION QUADRIFILAR helix antennas (QHAs) are often used to provide the broad beam circularly polarized patterns which are required for satellite communications [1]. The QHA consists of four helical conductors which are excited in phase quadrature at the feed point ...