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.

A Triple-Mode Sigma-Delta Modulator for Multi-Standard Wireless Radio Receivers

Abstract: A 1.8 V sigma-delta modulator with a 4 bit quantizer has been designed for GSM/WCDMA/WLAN receivers in a 0.18 um CMOS process. The modulator makes use of low-distortion sigma-delta modulator architecture and Pseudo-Data-Weighted-Averaging technique to attain high linearity over a wide bandwidth. Power dissipation is minimized by optimizing the architecture and by a careful design of analog circuitry. In GSM mode, the modulator achieves 96/104 dB peak SNR/SFDR over 100 kHz bandwidth and dissipates 18 mW at a sampling frequency of 32 MHz. The modulator achieves 92/68 dB peak SFDR and 77/54 dB peak SNR over a 2 MHz/10 MHz bandwidth and dissipates 23/39 mW at a sampling frequency of 64 MHz/160 MHz in WCDMA/WLAN.

Broadband stacked shorted patch antenna for mobile communication handsets

Abstract: Two designs of stacked shorted patch antennas with a low profile (antenna height less than 5 mm) and a wide bandwidth (larger than 10%) suitable for applications for GSM 1800 and GSM 900 cellular systems, respectively, are presented. In the designs, the upper and lower shorted patches have a common shorting wall, and are both printed on a dielectric substrate. Wide impedance bandwidth is obtained by adjusting the lengths of the upper and lower patches to be slightly different, leading to the excitation of two closely excited resonant modes. The experimental results are presented and discussed.

The identification of an intensity 'window' on the bioeffects of mobile telephony radiation.

Abstract: Purpose: The increased bioactivity ‘windows’ of GSM 900 and 1800 MHz radiations, (Global System for Mobile telecommunications) revealed recently by us and published in this issue, manifesting themselves as a maximum decrease in the reproductive capacity of the insect Drosophila melanogaster, were examined to discover whether they depend on the intensity of radiation-fields.Methods: In each experiment, one group of insects were exposed to the GSM 900 or 1800 radiation at 30 or 20 cm distances, respectively, from the antenna of a mobile phone, where the bioactivity ‘window’ appears for each type of radiation and another group was exposed at 8 or 5 cm, respectively, behind a metal grid, shielding both microwave radiation and the extremely low frequency (ELF) electric and magnetic fields for both types of radiation in a way that radiation and field intensities were roughly equal between the two groups. Then the effect on reproductive capacity was compared between groups for each type of radiation.Results: The...

Ultra-Miniaturized Low-Profile Angularly-Stable Frequency Selective Surface Design

Abstract: In this study, an ultra-miniaturized low-profile angularly-stable frequency selective surface (FSS) based on 2.5-dimension convoluted interwoven element is designed. The dimension of FSS element is 0.014λ0 × 0.014λ0, where the λ0 represents the free-space wavelength of resonance frequency. The thickness is only 0.0015λ0. When the FSS is illuminated by electromagnetic wave, the frequency selective properties perform stable under different incident angles up to 85° for both TE and TM polarization. For better understanding, the operation mechanism, the design procedure, distribution of surface current, and equivalent circuit are presented. A prototype of proposed FSS is fabricated, the measurement results prove the validity of simulated ones. To further improve the performance, using the same design procedure, the size and thickness of designed FSS have been reduced to 0.0053λ0 × 0.0053λ0 and 0.00061λ0, respectively. Since the resonance frequency of proposed FSS is adjustable at any desired frequency, an ultra-miniaturized low-profile angularly-stable FSS for GSM 900 band has been designed. The designed FSS can be applied in GSM shielding effectively.