Showing papers on "GSM frequency bands published in 2008"

Design of Ultrawideband Mobile Phone Stubby Antenna (824 MHz-6 GHz)

Abstract: An ultrawideband stubby antenna that covers all frequency bands between 824 MHz and 6 GHz, which include GSM 850 and 900, GPS, DVB-H US, DCS, PCS, UMTS, BT, WLAN 802.11b/g and WLAN 802.11a, with a VSWR better than 2.7:1 is described in this paper. The design procedure involves obtaining a wideband resonance from 1-6 GHz and using a matching network to compensate for the high capacitance of the antenna at the lower frequency band below 1 GHz. Parametric studies of this antenna are presented in this paper. The design was experimentally verified by constructing an ultrawideband antenna with a volume of 5 * 8 * 30 mm3. It is significant that the designed ultrawideband stubby antenna maintained a good impedance matching and radiation efficiency at all bands. An efficiency between 55 ~ 65% is achieved in the lower band including 824 ~ 960 MHz band required for the GSM 850 and GSM 900 systems, and an efficiency value of 67 ~ 88% is achieved at the rest of the bands starting with the GPS at 1575 MHz to 6 GHz.

A 120 watt, two-stage, LDMOS power amplifier IC at 1.8 GHz for GSM/EDGE applications

Abstract: A 120 Watt LDMOS radio frequency integrated circuit (RFIC) targeting 1.8 GHz GSM, EDGE, and Evolved EDGE base station applications has been developed using state of the art design techniques and LDMOS technology. The amplifier was designed to cover the 1.8 GHz to 2 GHz GSM bands, and performs exceptionally well under both GSM and EDGE conditions. The two-stage, single-chip design exhibits 27 dB of gain and delivers 132 Watts of output power (1 dB compression; 27 Volt DC supply) with an associated PAE of 51%. Under EDGE modulation, at an average output power of 46 Watts, the EVM is less than 1.6 % and the spectral re-growth is −63 dBc and −78 dBc at 400, and 600 kHz offsets, respectively. This is the highest power, 1.8 to 2 GHz, two-stage RFIC in an over-molded plastic package, reported to date.

3rd generation mobile communication multi-system combined equipment

Abstract: The invention belongs to an area of a mobile communication technology, which is a multi-system communication mixing equipment of the third generation. The mixing equipment uses a standard frame of 19 inches as the structure model and a standard joint with an N-K type is arranged in the panel as an input end or an output end of the signals and a SMA-K typed joint is arranged in the signal input end of each circuit as a monitoring port. Besides, a power testing and a standing wave testing module is arranged inside which is used for testing the monitored signals and connecting to the outside in the end form of the Agreement RS-485 or the Agreement RS-232; a wireless modem is arranged inside to modulate the monitored signals; a plurality of mixer combinations are used inside to enable the mixing system to be a 10-12 circuit. The invention can mix tens of communication systems including mobile television 600 which includes a third generation WCDMA, TD-SCDMA, TETRA 800, CDMA 800, GSM 900 and WLAN2500. The invention can also provide the imitating, numbering and remote monitoring, The equipment has fixed structure, low consumption and good stability.

A design of the multi-band chip antenna using meander line PIFA structure for mobile phone handset

Abstract: The paper introduces mobile handset multi-band chip antenna based on meander line PIFA structure. The proposed antenna uses an FR-4 substrate and demonstrated the ability to adjust characteristic impedance by adding parasite patch to ground and by coupling with base radiator. The fabricated antenna with the dimension of 4 mm height, 6 mm width and 28 mm length. The ground plane a dimension of 90 times 40 [mm], designed by a commercial software CST simulator. The experimental results show that the impedance bandwidth for (VSWRO) is 90(875 ~ 965) MHz in GSM 900 band operation and 380(1.670 ~ 2,050) MHz in DCS, PCS band operation. The maximum gains of antenna are 0.25 dBi, 2.21 dBi and 2.71 dBi at resonance frequencies and it has omni-directional pattern practically.

Miniaturization and Dual-Band Operation in Planar Microwave Components by Using Resonant-Type Metamaterial Transmission Lines

Abstract: In this work, it is shown that dual-band microwave components based on plusmn90deg metamaterial transmission lines can be miniaturized by implementing the artificial lines by means of complementary spiral resonators (CSRs) Such lines exhibit a composite right/left handed (CRLH) behavior Dual-band operation is achieved by designing the lines to provide a phase of -90o at the lower operating frequency (within the left handed band) and +90o phase shift at the upper frequency (within the right handed band) Size reduction, as compared to conventional implementations, is achieved by implementing the lines with a single unit cell, and thanks to the small electrical size of CSRs To illustrate the possibilities of the approach, a dual-band branch-line coupler based on metamaterial transmission lines implemented by means of CSRs is presented The device has been designed to be functional at the mobile GSM bands (f1= 09 GHz, f2= 18 GHz) As compared to the conventional branch line, a 40% size reduction is obtained The approach is fully compatible with planar technology

Adapting the WiMAX PHY layer for use in a GSM overlay system

Abstract: Many of todaypsilas communication systems use only a small fraction of their allocated bandwidth. Cooperative overlay systems can make use of unallocated transmission capacity in under-utilized frequency bands without causing significant interference. Measurements taken in the GSM frequency range showed, that there are remaining transmission resources in such a cellular system. Therefore, GSM is used as an exemplary licensed user system with bursty traffic and varying usage rates providing a reasonable remaining capacity that can be utilized by an overlay system. WiMAX provides a highly flexible solution that can be adapted to the specific requirements of an overlay system. By adding elements for signalling of the current spectrum usage of the underlying GSM system to the WiMAX frame, the WiMAX overlay system is able to react very fast to changing utilizations of the spectrum. Frequencies that are currently used by a GSM subscriber can be abandoned in a very short time, and frequencies that have been released for a certain period can easily be reclaimed for overlay usage.

Simulation Study of UWB Interference Effects on GSM 900 System

Abstract: The impact of UWB interference on GSM 900 was studied in view of Federal Communication Commission (FCC) regulations. The maximum UWB transmitter power levels that would cause 1dB performance degradation on GSM 900 receivers were determined. UWB densities were computed for different GSM cluster size and the results showed that there is no harmful interference for GSM 900 system.

Passive, active and absorbing frequency selective surfaces for wireless communication applications

Abstract: "March, 2009".%%%%%%%%Bibliography: p. 145-158.%%%%Introduction – Frequency selective surfaces – Absorb/transmit frequency selective surface absorber – Switchable frequency selective surface for wireless applications – Energy-saving glass characterisation – Frequency selective surface solution for energy-saving glass – Conclusion.%%%%This thesis presents three topics related to frequency selective surfaces (FSSs), namely bsorb/transmit FSSs, active FSSs and passive bandpass FSSs for energy-saving glass used in modern buildings. These three FSSs are unique in their design and functionalities. The absorb/transmit FSS is a novel dual-layer frequency selective surface for 5 GHz WLAN applications. This FSS can stop propagation of specific bands by absorbing as opposed to re ecting, while passing other useful signals. This is in contrast to the conventional Salisbury and Jaumann absorbers, which provide good absorption in the desired band while the out-of-band frequencies are attenuated. The second topic is a single-layer bandpass active FSS that can be switched between ON and OFF states to control the transmission in 2.45 GHz WLAN applications. Previously, researchers have focused on the bandstop and dual-layer versions of the active FSS. This is in contrast to the design presented in this thesis which is single-layer and provides extra advantage in a practical WLAN environment. Also the dc biasing techniques that were used for the active FSS design are easier to implement and provide good frequency stability for different angles of incidence and polarisations in both ON and OFF states. The last topic is on the use of a bandpass FSS in energy-saving glass panels used in building design. The manufacturers of these glass panels apply a very thin metal-oxide coating on one side of the glass panels to provide extra infrared (heat) attenuation. However, due to the presence of the coating, these energy-saving glass panels also attenuate communication signals such as GSM 900, GSM 1800/1900, UMTS and 3G mobile signals etc. This creates a major communication problem when buildings are constructed with windows of this glass. In this thesis, a solution to this problem is presented by designing and etching a cross-dipole bandpass FSS on the coated side of the glass to pass the useful signals while keeping infrared attenuation at an acceptable level. One of the advantages of this FSS design is that measured material values of the metal-oxide coating are used for simulations, which have not been done previously.%%%%%%%%166 p. ill. (some col.)

Automotive multi- and broadband monopole antenna for GSM, WLAN and UWB applications

Abstract: Two different approaches for an automotive multi-and broadband monopole antenna for GSM, WLAN and UWB applications will be presented. Both allow covering the complete relevant frequency range worldwide in one antenna structure. The two antennas consist of one broadband structure for frequencies above 1.7 GHz and an additional folded arm for the lower frequencies. The first approach is based on a disc-monopole. In addition it has a folded arm on its top to cover the mobile phone services GSM 900 and AMPS. It has a height of 60 mm. The second approach has a 5 mm reduced height. So it achieves a height of 55 mm, which is the typical goal of many car manufacturers. The antenna is based on a folded metal strip construction. The amplitude and phase behaviour of the two antennas were measured. The derived impulse responses will be discussed with focus on the UWB frequencies.

Mobile terminal and method for implementing double-mode and double-standby

Abstract: The invention provides a mobile terminal which is used to realize the dual mode and the dual stand-by of the TD-SCDMA and the GSM and a method thereof; the method includes step S402, step S404 and step S406, wherein the step S402 is that an antenna is arranged for receiving radio frequency signals; the step S404 is that a first wave filter is arranged between the antenna and a GSM radio frequency unit for attenuating signals of the TD-SCDMA frequency band; and the step S406 is that a second wave filter is arranged between the antenna and a TD-SCDMA radio frequency unit for attenuating signals of the GSM frequency band; thus, the invention has the advantages of resolving the problem of the mutual interference of two systems and realizing the dual mode and the dual stand-by functions.

Design of HAC compatible mobile phone with LC band-stop filter embedded in PWB

Abstract: People who have some level of hearing loss normally have to use hearing aids to improve their hearing ability. Digital mobile phones can cause interference to hearing aids because of the electromagnetic (EM) energy emitted by the phone's antenna, backlight, GSM burst noise and other components. As required by the FCC, a certain percentage of all sold mobile phone models must be hearing aid compatibility (HAC) compatible. Even though some HAC compliant phones are available on the market, it still requires huge effort in doing so. Therefore, it is quite urgent for mobile phone makers to design HAC compatible mobile phones, in which the strength of the near-field EM fields of the phones reduces to a certain level in the HAC region. According to the FCC requirement, the E-field strength limits for low and high GSM bands are 266.1V/m and 84.1V/m, respectively, whereas the H-field strength limits are 0.804A/m and 0.254A/m. To meet this HAC requirement, approaches for reducing the undesirable effects of the near field EM scattering around the HAC region need to be developed. In particular, a metallization termination technique was used to reduce the EM field scattering at the edge of the printed wring board. A high-impedance thin layer was employed to reduce the EM field scattering at the edge of the PWB. However, these two approaches might cause a reduction of the total radiated power (TRP). In this paper, an alternative way for designing HAC compatible mobile phones is proposed.

A GSM/EDGE transmitter in 0.13-μm CMOS using offset phase locked loop and direct conversion architecture

Abstract: A GSM/EDGE transmitter implemented in 0.13-mum CMOS using offset phase locked loop and direct conversion architecture is presented. The transmitter consists of a DCT, an OPLL with a TXVCO, a fractional-N synthesizer with a RFVCO and LDO regulators. The transmitter delivers 1.5 dBm output power with 1.2deg rms phase error and the modulation spectrum at 400 kHz offset is better than -62 dBc in high band GSM mode. In high band EDGE mode, it has maximum 4 dBm output power with 0.5 dB gain step per bit for 36 dB dynamic range and 2% rms error vector magnitude. The current consumption of high band is 171 mA at GSM mode and 169 mA at EDGE mode under proper output power level for PA. This chip is housed in a 56-pin QFN package.

Multi-band Antenna with Minimalization of Radiation towards Head

Abstract: Intensive development of cellular personal communications system has been ob- served lately. Thus, protection of a man, and especially protection of his head against non-ionizing electromagnetic radiation generated by cellular telephones is becoming one of the most important problems. The results of elaborated microstrip antennas which have minimized radiation towards the user's head are presented in this paper. 1. INTRODUCTION Wireless communication has been the fastest growing sector of telecommunication in recent years. Substantial contributions to this growth has been made in Europe, where many such systems have been developed: GSM (Global System for Mobile Communication), operating in the 900MHz band, DCS-1800 (Digital Personal Communication System), using the 1800MHz band DECT (Digital Eu- ropean (Enhanced) Cordless Telecommunications, using the 1900MHz band and UMTS (Universal Mobile Telecommunications System) working in band circle about 2GHz. Some experts predict that by the end of new century there will be more cordless than conventional telephones in use. In order to achieve an easy access to information, more and more modern cellular phones, which are able to work in two or three bandwidths, are being invented. This is why it is important to determine possible health efiects of using such devices. New trends require antennas to be cheap to produce and to meet tough operational requirements. The following requirements should be met by the antenna: † a radiation pattern ensuring reliable communication regardless of the antenna's orientation; † a wide operational frequency band, so that the spectrum of transmitted information should not be distorted; † a minimum impact on the biological tissue of the user, to avoid health risks; † little sensibility of the antenna parameters to the user's proximity; † small size to facilitate mounting the antenna and using the telephone. It is clear that some of these requirements are mutually exclusive, so a compromise has to be worked out in the designing process. 1m GSM 900 (0.8W) Class 5 0.386W/m 2 0.09W/m 2 0.1W/m 2 GSM 900 (2W) Class 4 1.06W/m 2 0.26W/m 2

The channel capacity of a GSM frequency hopping network with intelligent underlay-overlay

Abstract: In this paper a complete step by step method is described to increase the capacity of Global System for Mobile Communication (GSM) using the Intelligent Underlay Overlay(IUO) with frequency hopping and Discontinuous Transmission (DTX). The IUO splits the available frequencies into two layers, super and regular. Super layer frequencies have tighter reuse factor and can be accessed by only mobile stations (MS) having good C/I ratio while the regular frequencies can be used by MSs throughout the cell. The most promising work of this paper is that C/I ratio (hence reuse factor) is obtained by considering the first tier co-channel cells are also using IUO network structure. Analysis is performed by taking some default parameters into account shows that capacity enhancement up to 31 percent can be obtained with respect to a normal frequency hopping network.

Electromagnetic Radiation Study of Commercial Cellular Phones with a TEM Cell for Biological Applications

Abstract: Electromagnetic radiation effects of the GSM 900 and 1800 commercial cellular phones were estimated using a TEM cell. A standard TEM cell was modified with a double-ended monopole antenna as a signal leader for incoming and outgoing signals between the TEM cell's outer surface. The electric field distribution was studied with parameters such as the cellular phone position, polarization, dialing type, and dialing frequency. The field uniformity can be improved with either the use of a shorter signal leader or the TEM cell with a reduction in size. It also showed a good agreement between the results from experiments and simulations. With the proposed exposure technique, the Specific Absorption Rate (SAR) result from simulation also indicated the energy absorption by the test sample, confirming a potential usage of the proposed setup in studies related to biological applications.

A Novel Low Profile Chip Antenna for GSM/DCS/PCS Mobile Phone

Abstract: A novel internal chip antenna with low profile for GSM/DCS/PCS band mobile phone is presented. The size of the antenna is 13.5 × 5.8 × 3.4 mm3. The minimization of the antenna is realized by using meander line and spiral line pattern printed on FR-4 with dielectric constant 4.4. The meander line is designed on bottom and top surface connected with via, which assures the GSM frequency in small size. Wide-bandwidth of the upper band is realized by overlapping high order resonances of both meander line and spiral line. The details of the computed results and experiment results for the proposed design are presented.

Multi-band Internal antenna for DVB-H and GSM services

Abstract: We propose a multi-band internal antenna for the DVB-H and the GSM services. The proposed antenna consists of a tunable PIFA for the DVB-H service and a dual band folded monopole for the GSM 900 and the DCS 1800. The resonant frequencies of the designed antenna are independently adjusted. It can be used for a complex mobile set for a broadcasting service.

RIM-shaped multi-frequency band slot-strip antenna

Abstract: Modern mobile handset devices are required to operate at multiple frequency bands so as to provide various services [1,2]. As is well known, for the future mobile communication systems (the emerging third generation or beyond), the frequency band around 2 GHz is very wide (GSM1850, GSM1900, DCS, PCS, UMTS, WiBro), in addition to existing GSM bands around 900 MHz. Additionally, Bluetooth and WLAN systems at 2.45 GHz ISM band, as well as GPS at 1.57 GHz are desired to integrate into a handset device. This results in a total bandwidth requirement of 1 GHz (from 1.5 to 2.5 GHz) near 2 GHz. Operation around 5 GHz (IEEE 802.11 j/a) for WLAN applications is also required for personal communication handsets.