Theoretical and experimental investigation of adaptive antenna impedance matching for multiband mobile phone applications

2005 ◽  
Author(s):  
Libo Huang
Keyword(s):  
Experimental Investigation ◽  
Mobile Phone ◽  
Impedance Matching ◽  
Adaptive Antenna ◽  
Mobile Phone Applications ◽  
Antenna Impedance

scholarly journals A Wideband Antenna with Circular and Rectangular Shaped Slots for Mobile Phone Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wei-Hua Zong ◽  
Xiao-Mei Yang ◽  
Xia Xiao ◽  
Shan-Dong Li ◽  
Xiang-Yang Wei ◽  
...  
Keyword(s):  
Transmission Line ◽  
Mobile Phone ◽  
Impedance Matching ◽  
Ground Plane ◽  
Slot Antenna ◽  
Microstrip Transmission Line ◽  
Rectangular Shape ◽  
Antenna Size ◽  
Wideband Antenna ◽  
Mobile Phone Applications

A wideband slot antenna for mobile phone applications is proposed. The antenna has two slots with open ends etched on the opposite edges of the ground plane. The main slot, of total length of 59 mm, is composed of a rectangle connected to a circle having radius of 5 mm. Another slot, having a rectangular shape with width of 2.8 mm and length of 26 mm, is employed to enhance the antenna bandwidth. The slots are fed by means of a rectangular monopole connected to a circular patch joined to a bent 50 Ω microstrip transmission line forming two right angles. To obtain a wideband impedance matching, the upper edge of the monopole and a part of the feeding line evolve along the top edge of the two slots. To reduce the antenna size, the upper part of the board above the slot (just 3 mm from the slot) is folded vertically to the ground plane. The measured bandwidth of the antenna is 0.698–1.10 GHz and 1.64–2.83 GHz covering LTE700/2300/2500, GSM850/900/1800/1900, and UMTS bands.

scholarly journals Wideband Dual-Element Antenna Array for MIMO Mobile Phone Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yuanqiang Wang ◽  
Jie Yang ◽  
Shangfu Hao ◽  
Xiao Zhang
Keyword(s):  
Mobile Phone ◽  
Antenna Array ◽  
Correlation Coefficient ◽  
Impedance Matching ◽  
Ground Plane ◽  
Ergodic Capacity ◽  
Planar Antenna ◽  
Antenna Size ◽  
Mobile Phone Applications ◽  
Planar Antenna Array

A printed dual-element antenna array for LTE MIMO mobile phone applications is presented in this paper. The two array elements are symmetrically placed with the same dimensions, and each of the them consists of a novel driven strip and a wandering shorting strip. The driven strip is a whole loop, which improves the impedance matching for the upper band. Therefore, the bandwidth coverage is expanded and the antenna size is minimized at the same time. In addition, thanks to the protruded ground on the ground plane, the antenna isolation between the two array elements is significantly enhanced. The proposed planar antenna array successfully covers the seven operating bands of GSM850/900/1800/1900/UMTS2100/LTE2300/2500, and the isolation is more than 10 dB. The prototype was fabricated and tested, withSparameters, efficiency, radiation patterns, envelop correlation coefficient (ECC), and ergodic capacity presented. From the measured results, it is indicated that the antenna array has excellent and reliable performances when it is applied in MIMO applications.

A SYSTEMATIC ANALYSIS OF THE EFFECTS OF MOBILE PHONE APPLICATIONS ON PHYSICAL ACTIVITY

2020 ◽  
Vol 2020 ◽  
pp. 1483-1484
Author(s):  
Masoumeh Hosseinpour ◽  
◽  
Ralf Terlutter ◽  
Holger Roschk
Keyword(s):  
Physical Activity ◽  
Mobile Phone ◽  
Systematic Analysis ◽  
Mobile Phone Applications

Implementasi Keamanan pada Transaksi Data Menggunakan Sertifikat Digital X.509

2017 ◽  
Vol 8 (1) ◽  
pp. 1-10
Author(s):  
Is Mardianto ◽  
Kuswandi Kuswandi
Keyword(s):  
Mobile Phone ◽  
Web Service ◽  
Data Exchange ◽  
User Authentication ◽  
Digital Certificate ◽  
Security Issues ◽  
Diffie Hellman ◽  
Digital Certificates ◽  
Mobile Phone Applications ◽  
Secure Hash Algorithm

Security issues have become a major issue on the Internet. One of the security methods that are widely used today is to implement a digital certificate. Digital certificates have evolved over time, one of which is the X.509 digital certificate. Digital certificates have been widely used as authentication applications, web network authentication and other authentication systems that require digital certificates. This research is carried out by implementing an X.509 digital certificate technology as a mobile web service with its client. Secure Hash Algorithm (SHA), Diffie-Hellman, and Advanced Encryption Standard (AES) are used to secure the data exchange transaction between the web service and mobile phone. SHA algorithm will be used for user authentication, Diffie-Hellman algorithm will be used for public key exchange and AES algorithms will be used for symmetric cryptography data. The results of the application of digital certificates, the SHA algorithm, Diffie-Hellman, and AES in mobile phone applications, provide security application running on web service. Index Terms—Digital Certificate, X.509, SHA, Diffie Hellman, AES

scholarly journals Optimum power transfer in RF front end systems using adaptive impedance matching technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Alibakhshikenari ◽  
Bal S. Virdee ◽  
Leyre Azpilicueta ◽  
Chan H. See ◽  
Raed Abd-Alhameed ◽  
...  
Keyword(s):  
Impedance Matching ◽  
Adaptive Antenna ◽  
Power Transfer ◽  
Control Loops ◽  
Matching Networks ◽  
Front End ◽  
Rf Front End ◽  
Matching Technique ◽  
Digital Circuitry ◽  
Communications System

AbstractMatching the antenna’s impedance to the RF-front-end of a wireless communications system is challenging as the impedance varies with its surround environment. Autonomously matching the antenna to the RF-front-end is therefore essential to optimize power transfer and thereby maintain the antenna’s radiation efficiency. This paper presents a theoretical technique for automatically tuning an LC impedance matching network that compensates antenna mismatch presented to the RF-front-end. The proposed technique converges to a matching point without the need of complex mathematical modelling of the system comprising of non-linear control elements. Digital circuitry is used to implement the required matching circuit. Reliable convergence is achieved within the tuning range of the LC-network using control-loops that can independently control the LC impedance. An algorithm based on the proposed technique was used to verify its effectiveness with various antenna loads. Mismatch error of the technique is less than 0.2%. The technique enables speedy convergence (< 5 µs) and is highly accurate for autonomous adaptive antenna matching networks.

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