Application of Simulation Software in Mobile Communication Course

Author(s):  
Fangni Chen ◽  
Zhongpeng Wang
2014 ◽  
Vol 875-877 ◽  
pp. 2219-2223 ◽  
Author(s):  
Zhong Liang Deng ◽  
Xing Jie Cao

Tunable bandpass filters are generally preferred and are used extensively in the mobile communication systems. In this paper, a design of the RF MEMS tunable combline bandpass filter is proposed. Firstly, the theory of the RF MEMS tunable combline bandpass filter is presented. Secondly, a combline bandpass filter which have a tunable frequency range from 18GHz to 27GHz is designed and simulated by using the EDA simulation software. Its bandwidth is about 1GHz in the tunable frequency range. From the simulation results, the designed filter is not only compact and effortless to fabricate but also relatively superior in some aspects.


2021 ◽  
Author(s):  
Jagbir Kaur ◽  
Suyeb Ahmed Khan

The 5G mobile communication systems are the “next generation” communication systems. They are capable of providing numerous benefits to the mobile phone users. But, whether they are safe to use is still a topic of concern. This study investigates the thermal safety of 5G mobile phone frequency. A three dimensional multi-layered skin tissue is exposed to 60 GHz frequency from a mobile patch antenna. The simulation software COMSOL Multiphysics is employed to map the electric field distribution and the temperature distribution within the exposed domain. The peak temperature (37.36°C) is estimated in the subcutaneous fat layer of the skin tissue. The temperature peak is very short lived and the steady state temperature is same as the core body temperature. The results suggest that the temperature rise caused by the 5G mobile phone radiation exposure is not capable of causing the thermal burns in the exposed tissue. Therefore, the 5G mobile communication frequency of 60 GHz can be considered “thermally” safe.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Tangyao Xie ◽  
Jianguo Yu ◽  
Yao Li ◽  
Zhen Yu ◽  
Ziheng Lin

This study proposes and designs a multiband branch antenna with a structure that imitates the Chinese classical pattern structure. The antenna radiator’s structure is a symmetrical rectangular stub fused with a Chinese classical pattern structure, and the rectangular stub is bent so that the outer and inner stubs are coupled to each other to generate multiple frequency bands. Microstrip line feeding is the feeding mode, and the grounding plate is a trapezoidal structure formed by subtracting two triangles from a rectangle. The overall size of the antenna is 60 × 60 × 1.6 mm3, and the dielectric board adopts FR4. The substrate dielectric constant εr = 4.4, the thickness h = 1.6 mm, and the dielectric loss tangent tanδ = 0.02. For antenna modeling and parameter optimization, HFSS electromagnetic simulation software is used. The antenna can cover 1.49 to 1.60 GHz, 1.87 to 2.51 GHz, and 4.63 to 5.34 GHz and generate three main frequencies: 1.57, 2.15, and 5.06 GHz, according to test result. The antenna has omnidirectional radiation characteristics and can be widely used in future mobile communication network coverage.


TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.


TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 4-11
Author(s):  
MOHAMED CHBEL ◽  
LUC LAPERRIÈRE

Pulp and paper processes frequently present nonlinear behavior, which means that process dynam-ics change with the operating points. These nonlinearities can challenge process control. PID controllers are the most popular controllers because they are simple and robust. However, a fixed set of PID tuning parameters is gen-erally not sufficient to optimize control of the process. Problems related to nonlinearities such as sluggish or oscilla-tory response can arise in different operating regions. Gain scheduling is a potential solution. In processes with mul-tiple control objectives, the control strategy must further evaluate loop interactions to decide on the pairing of manipulated and controlled variables that minimize the effect of such interactions and hence, optimize controller’s performance and stability. Using the CADSIM Plus™ commercial simulation software, we developed a Jacobian sim-ulation module that enables automatic bumps on the manipulated variables to calculate process gains at different operating points. These gains can be used in controller tuning. The module also enables the control system designer to evaluate loop interactions in a multivariable control system by calculating the Relative Gain Array (RGA) matrix, of which the Jacobian is an essential part.


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