GSM frequency bands

About: GSM frequency bands is a research topic. Over the lifetime, 559 publications have been published within this topic receiving 5067 citations.

New dual-band Frequency Selective Surfaces for GSM frequency shielding

Abstract: This paper describes a new element for Frequency Selective Surfaces (FSS), with dual-band stop behaviour in the two mobile communication frequency ranges GSM900 and GSM1800. Easy manufacturing as well as low performance dependency on incidence angle and direction of polarization were key factors for the development. The FSS was realized as wallpaper for walls with defined dielectric characteristics, while a second variant can be used on arbitrary substrates. An attenuation of 20dB was desired for the GSM downlink bands, providing maximum transparency at broadcast and WLAN frequencies at the same time.

Impedance matching for a dual band power amplifier

Abstract: An exciter matching circuit (125), interstage matching circuit (134), and harmonic filter matching circuit (140) match impedances at the input to a two-stage power amplifier (130), between the first stage (132) and the second stage (136) of the power amplifier (130), and at the output of the power amplifier (130) for more than one frequency band of interest. In a GSM/DCS dual band radiotelephone (101), the matching circuits (124, 134, 140) provide low return loss at 900 MHz when the dual band transmitter (110) is operating in the GSM mode. The harmonic filter matching circuit (140) also filters out signals at 1800 MHz, 2700 MHz, and high order harmonics. When the dual band transmitter (110) is in DCS mode, however, the matching circuits (124, 134, 140) provide a low return loss at 1800 MHz and filter out signals at 2700 MHz and harmonics of 1800 MHz.

FH-GSM frequency hopping GSM

Abstract: The GSM system of today is evolving towards smaller cells and higher traffic capacity. The need for microcell and even picocell systems will be greatly increased in the near future. One of the most important factors will then be to provide high traffic capacity and to provide an easy way of performing frequency planning for the system operator. In this paper we present results from system simulations based on the GSM recommendation phase two. We show that the use of power regulation in both up- and downlink in combination with discontinuous transmission (DTX) and slow frequency hopping makes it possible to decrease the frequency reuse distance below 3/9 whilst maintaining system performance. Results from simulations with different frequency reuse distances are presented. System characteristics such as capacity, quality and robustness are evaluated and compared to a fixed plan reference system without frequency hopping or DTX. >

A Meandered Loop Antenna for LTE/WWAN Operations in a Smart Phone

Abstract: —This paper presents a multiband meandered loop antenna for smart phone applications. The proposed antenna which features a meandered folded-loop generates two resonance modes in the LTE/GSM bands. The current distributions of the excited resonance modes are analyzed to investigate the mode characteristic. By using a capacitively coupled feed on the backplane, the impedance bandwidth is broadened to cover LTE/WWAN bands. The simulation performed in this research used a high frequency structure simulator (HFSS) to optimally design the antenna, and a practical structure was constructed for the test. Details of the various antenna parameters are presented and discussed in this paper.

Comparison between radiation efficiencies of phone antennas and radiated power of mobile phones measured in anechoic chambers and reverberation chamber

Abstract: Chalmers University and Bluetest AB have developed a reverberation chamber that can be used to measure radiation efficiency of phone antennas and the radiated power of mobile phones. This paper describes the verification of the reverberation chamber measurements by comparison with two anechoic chambers. The total radiated power of each of ten different mobile phone models was measured. In addition, the antennas on eight of the phone models were fed by a cable (spare set of phones), and the radiation efficiencies were measured. Both the antenna radiation efficiency and the radiated power were measured in the presence of a head-and-shoulder phantom. The handsets were measured in only one position - the so-called left talk, 45/spl deg/ user-intended position. The phone tests were performed in the GSM 900 (GSM), GSM 1800 (DCS) and GSM 1900 (PCS) bands. There exists high correlation in the results of the radiation efficiencies and radiated power measured in the reverberation chamber and two different anechoic chambers, respectively. The agreement between the results of corresponding active and cable-fed devices is also good. Frequency stirring, platform stirring and polarization stirring are important for achieving accuracy when measuring in the reverberation chamber.