Conformal Antenna Array for Millimeter-Wave Communications: Performance Evaluation

In this paper, we study the influence of the radius of a cylindrical supporting structure on radiation properties of a conformal millimeter-wave antenna array. Bent antenna array structures on cylindrical surfaces may have important applications in future mobile devices. Small radii may be needed if the antenna is printed on the edges of mobile devices and in items which human beings are wearing, such as wrist watches, bracelets and rings. The antenna under study consists of four linear series-fed arrays of four patch elements and is operating at 58.8 GHz with linear polarization. The antenna array is fabricated on polytetrafluoroethylene substrate with thickness of 0.127 mm due to its good plasticity properties and low losses. Results for both planar and conformal antenna arrays show rather good agreement between simulation and measurements. The results show that conformal antenna structures allow achieving large angular coverage and may allow beam-steering implementations if switches are used to select between different arrays around a cylindrical supporting structure.Comment: Keywords: conformal antenna, millimeter-wave communications, patch antenna array. 11 pages, 10 figures, 1 tabl

Millimeter wave fifth generation (5G) antenna for smartphone application

In this paper, a single element antenna is designed at millimeter-wave frequency bands for future 5G smartphone applications. The configuration of proposed antenna is multiple L-slots on the ground plane which is designed on a low cost FR4 board. The antenna covers a frequency range between 28 to 35 GHz with a higher bandwidth 4.7 GHz. The antenna shows an excellent performance when integrated with the mobile phone application. The single element antenna exhibits a maximum radiation pattern around 5.945 dBi

Analysis of Transmission Properties of Sludge Biochar Composites in the C-Band

In order to pave the way for the widespread use of eco-friendly materials for novel applications, there is a growing need for morphological, mechanical and electrical, and microwave characterization techniques. The measurement of scattering parameters is an accurate technique for the microwave characterization of novel materials, but it requires a number of components, including waveguides, adapters, and so on. The band of measurements is also limited to the working band of the waveguide used. A method of retrieving waveguide scattering parameters from permittivity values is devised. The method is validated with measurements of the scattering parameters in a waveguide. The method is tested with composites based on biochar derived from sewage sludge and a standard epoxy sample. The addition of biochar considerably reduces transmission scattering and is found to be a suitable candidate for filling composite materials

CogCell: Cognitive Interplay between 60GHz Picocells and 2.4/5GHz Hotspots in the 5G Era

Rapid proliferation of wireless communication devices and the emergence of a variety of new applications have triggered investigations into next-generation mobile broadband systems, i.e., 5G. Legacy 2G--4G systems covering large areas were envisioned to serve both indoor and outdoor environments. However, in the 5G-era, 80\% of overall traffic is expected to be generated in indoors. Hence, the current approach of macro-cell mobile network, where there is no differentiation between indoors and outdoors, needs to be reconsidered. We envision 60\,GHz mmWave picocell architecture to support high-speed indoor and hotspot communications. We envisage the 5G indoor network as a combination of-, and interplay between, 2.4/5\,GHz having robust coverage and 60\,GHz links offering high datarate. This requires an intelligent coordination and cooperation. We propose 60\,GHz picocellular network architecture, called CogCell, leveraging the ubiquitous WiFi. We propose to use 60\,GHz for the data plane and 2.4/5GHz for the control plane. The hybrid network architecture considers an opportunistic fall-back to 2.4/5\,GHz in case of poor connectivity in the 60\,GHz domain. Further, to avoid the frequent re-beamforming in 60\,GHz directional links due to mobility, we propose a cognitive module -- a sensor-assisted intelligent beam switching procedure -- which reduces the communication overhead. We believe that the CogCell concept will help future indoor communications and possibly outdoor hotspots, where mobile stations and access points collaborate with each other to improve the user experience.Comment: 14 PAGES in IEEE Communications Magazine, Special issue on Emerging Applications, Services and Engineering for Cognitive Cellular Systems (EASE4CCS), July 201

Bi-directional Beams Waveguide Slotted Antenna at Millimeter Wave

This paper focused on designing a bi-directional beams waveguide slotted antenna at millimetre wave spectrum. Waveguide slotted antenna is known for its highly directional pattern. By having bi-directional pattern, the capacity of system coverage can be expanded. The design is implemented by using antenna slot theory on a waveguide structure. The slotted are made on two wall surfaces and the performance is compared to the slotted on single wall. The two models designs are simulated using Computer Simulation Technology (CST) microwave software. The simulation results show that both models operate at 30 GHz with minimum reflection coefficient of -24.63 and -25.01 dB respectively. The two models achieved a fair high gain at 15.5 dB and 13.3 dB with directional beamwidth of 8.9 degree. The proposed bi-directional beams structure achieved a comparable gain in both directions when compared to the single direction

Design of Wideband Slot Array Antenna by Groove Gap Waveguide in Millimeter Waves

The newly introduced gap waveguide technology offers non-contact waveguide configurations so that the good electrical contact between different metallic layers can be avoided. Thereby, the gap waveguide structures are relatively simple to manufacture, especially at millimeter and sub-millimeter wave frequencies. This work systematically presents a high-efficiency corporate-fed slot array antenna based on groove gap waveguide in the millimeter waves. A cavity-backed slot sub-array is firstly designed in a groove gap waveguide cavity. The cavity is fed through a coupling hole from groove gap waveguide distribution network at the bottom layer. The sub-array is numerically optimized in an infinite array environment. Low side lobes are obtained in the both E- and H-planes by diagonal placement of the radiation slot rotating by 45 degrees. Furthermore, the radiation narrow slot pair is adopted so that the good cross polarization is achieved. The fabricated antenna depicts more than 25% bandwidth with input reflection coefficient better than -8 dB and the aperture efficiency higher than 60% with around 25 dBi realized gain between 70 and 90 GHz. The measured cross polarization level is below -27 dB, which satisfies the ETSI standard

128-QAM Based mm-Wave Communication (5G) Architecture

Demand for bandwidth can never be fulfilled with any definite amount. Population is growing at a high speed which also causes an increase in the demand for bandwidth. Currently available bands ranging up-to 10 GHz is at the edge of saturation. So a newer and unutilized bandwidth is mandatory for the fulfillment of the increasing bandwidth demand. The millimeter wave band which is fully used. This band offers a wide range of bandwidth (30 GHz ~ 300 GHz). A slight part of this band, the E-band, has been used in the design of the 5G network proposed in this paper. Single-carrier frequency-division multiple access (SC-FDMA) and orthogonal frequency-division multiple access (OFDMA) have been proposed for the uplink and downlink multiple access respectively. A Rayleigh fading channel is used as the propagation environment along with considering different losses at sea level (T = 0 ˚C, P = 760 mm Hg, H2O = 1 gm/m3). 128-quadrature amplitude modulation (QAM) has been used as the principle modulation technique. Also, the use of adaptive beam-forming antennas ensure an increased coverage of about 2 km