-A reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 x 50 x 1.57 (3925mm 3 ), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching "ON" either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching "ON" both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied.
We report on a fast, easily implemented method to determine all the geometrical alignment errors of a laser tracker, to high precision. The technique requires no specialist equipment and can be performed in less than an hour. The technique is based on the determination of parameters of a geometric model of the laser tracker, using measurements of a set of fixed target locations, from multiple locations of the tracker. After fitting of the model parameters to the observed data, the model can be used to perform error correction of the raw laser tracker data or to derive correction parameters in the format of the tracker manufacturer's internal error map. In addition to determination of the model parameters, the method also determines the uncertainties and correlations associated with the parameters. We have tested the technique on a commercial laser tracker in the following way. We disabled the tracker's internal error compensation, and used a five-position, fifteen-target network to estimate all the geometric errors of the instrument. Using the error map generated from this network test, the tracker was able to pass a full performance validation test, conducted according to a recognized specification standard (ASME B89.4.19-2006). We conclude that the error correction determined from the network test is as effective as the manufacturer's own error correction methodologies.
Abstract-This paper presents the design of a low-profile compact printed antenna for fixed frequency and reconfigurable frequency bands. The antenna consists of a main patch, four sub-patches, and a ground plane to generate five frequency bands, at 0.92, 1.73, 1.98, 2.4, and 2.9 GHz, for different wireless systems. For the fixed-frequency design, the five individual frequency bands can be adjusted and set independently over the wide ranges of 18.78%, 22.75%, 4.51%, 11%, and 8.21%, respectively, using just one parameter of the antenna. By putting a varactor (diode) at each of the sub-patch inputs, four of the frequency bands can be controlled independently over wide ranges and the antenna has a reconfigurable design. The tunability ranges for the four bands of 0.92, 1.73, 1.98, and 2.9 GHz are 23.5%, 10.30%, 13.5%, and 3%, respectively. The fixed and reconfigurable designs are studied using computer simulation. For verification of simulation results, the two designs are fabricated and the prototypes are measured. The results show a good agreement between simulated and measured results.Index Terms-Cognitive radio, fixed antenna, independent control, multiband antenna, reconfigurable antenna, small antenna, wide tuning range.
Fifth generation (5G) envisages a “hyperconnected society” with an enormous number of interconnected devices, anywhere and at any time. Edge computing plays a pivotal role in this vision, enabling low latency, large traffic volumes, and improved quality of experience. The advent of 5G and edge computing encourages vertical industries to develop innovative services, which can meet the challenging demands coming from consumers. However, economic feasibility is the ultimate factor that determines the viability of a new service. Hence, effective techniques for the economic assessment of such services are needed. This paper analyzes the provision of immersive media services in crowded events, through a cloud‐enabled small cell network owned by a neutral host, and offered in multitenancy to different mobile network operators. We initially develop a planning model to predict the required compute, storage, and radio resources. Taking into account dynamic factors such as service penetration and price evolution, we then provide a number of economic indices, such as net present value, internal rate of return, and expected payback period to assess the viability of a potential investment in a 5G infrastructure for immersive media services. The presented analysis will guide small cell network operators in the provision of 5G innovative media services.
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