Showing papers on "GSM frequency bands published in 2015"
14 Apr 2015
TL;DR: Analytical modeling of passive rectifying circuits and the harvesting of electromagnetic (EM) power from intentionally generated as well as from ubiquitous sources are presented and the model provides an accurate method of determining the output characteristics of rectification circuits.
Abstract: In this paper, analytical modeling of passive rectifying circuits and the harvesting of electromagnetic (EM) power from intentionally generated as well as from ubiquitous sources are presented. The presented model is based on the linearization of rectifying circuits. The model provides an accurate method of determining the output characteristics of rectifying circuits. The model was verified with Advance Design System (ADS) Harmonic balance (HB) simulations and measurements. The results from the presented model were in agreement with simulations and measurements. Consequently design considerations and trade-off of radio frequency (RF) harvesters are discussed. To verify the exploitation of ambient RF power sources for operation of sensors, a dual-band antenna with a size of ~λ/4 at 900MHz and a passive dual-band rectifier that is able to power a commercial Thermo-Hygrometer requiring ~1.3V and 0.5MΩ from a global system for mobile communications (GSM) base station is demonstrated. The RF power delivered by the receiving dual-band antenna at a distance of about 110 m from the GSM base station ranges from -27 dBm to -50 dBm from the various GSM frequency bands. Additionally, wireless range measurements of the RF harvesters in the industrial, scientific and medical (ISM) band 868MHz is presented at indoor conditions.
36 citations
TL;DR: Investigations showed that the GSM 900 system is the dominant source of exposure – BTS on platforms, and handsets – used by passengers present nearby during the tube drive and the level of this exposure of engine-drivers does not exceed 2.5 V/m.
Abstract: Antennas from various wireless communications systems [e.g. mobile phones base transceiver stations (BTS) and handsets used by passengers, public Internet access, staff radiophone transmitters used between engine-drivers and traffic operators] emitting radiofrequency electromagnetic radiation (RF-EMR) are used inside underground metro public transportation. Frequency-selective exposimetric investigations of RF-EMR exposure inside the metro infrastructure in Warsaw (inside metro cars passing between stations and on platforms) were performed. The statistical parameters of exposure to the E-field were analyzed for each frequency range and for a total value (representing the wide-band result of measurements of complex exposure). The recorded exposimetric profiles showed the dominant RF-EMR sources: handsets and BTS of mobile communication systems (GSM 900 and UMTS 2100) and local wireless Internet access (WiFi 2G). Investigations showed that the GSM 900 system is the dominant source of exposure – BTS ...
16 citations
19 Oct 2015
TL;DR: In this paper, the authors presented four meandered MIMO antennas printed in symmetric configuration on top and bottom no-ground edges of the substrate, and the decoupling technique used in the design involves four ground slots and two coupled ground extensions.
Abstract: This paper presents four meandered MIMO antennas printed in symmetric configuration on top and bottom no-ground edges of the substrate. Two of the four MIMO antennas are coupled fed monopoles covering GSM 900/GSM 1800/1900, UMTS and WLAN frequencies whereas, the other two MIMO antennas are direct fed monopoles covering LTE 700 and WLAN 2.45 GHz. The substrate used is FR-4 with relative permittivity of 4.35 and an overall volume of 230 × 176 × 0.8 mm3. Each antenna covers an area of approximately 75 × 50 mm2. The decoupling technique used in the design involves four ground slots and two coupled ground extensions. The isolation performance of the MIMO antennas is better than 15 dB over all the cellular bands covered by the antennas. The simulated and measured results substantiate a good performance of the MIMO antennas.
14 citations
TL;DR: This paper presents how COST-231 Hata model is chosen and optimized for path loss prediction in suburban area of Tarakan, Indonesia in the GSM 900 MHz system and how this optimized model is successfully improved and would be more reliable to be applied in theTarakanGSM900 MHz system for path losses prediction.
Abstract: This paper present how COST-231 Hata model is chosen and optimizedfor path loss prediction in suburban area of Tarakan, Indonesia in the GSM 900 MHz system.Thispredicted and optimized path loss model is based on the empirical measurement collected in the GSM system on Tarakan City. It is developed by comparing the calculatedpath loss from collected measurements with the well-known path loss models within applicable frequency range of GSM system, such as COST-231 Hata, Ericsson, SUI, Walfish, ECC-33, and Lee Model. The COST-231 Hata model was chosen based on the closest and smallest mean error ascompared to the measured path loss. This optimized COST-231 Hata model is implemented in the path loss predictionduring the validation process. Thus, this optimized model is successfully improved and would be more reliableto be applied in the TarakanGSM900 MHz system for path loss prediction. DOI: http://dx.doi.org/10.11591/telkomnika.v14i1.7470
12 citations
21 Feb 2015
TL;DR: The PIFA antenna with multiband resonance for GSM 900, GSM 1800, WLAN 2400MHz, Bluetooth, WiMAX, 3G, 4G and UWB frequency from 3.1-10.6 GHz application is presented and results are compared with other pervious researches.
Abstract: In this paper the PIFA antenna with multiband resonance for GSM 900, GSM 1800, WLAN 2400MHz, Bluetooth, WiMAX, 3G, 4G and UWB frequency from 3.1-10.6 GHz application is presented. Slots or stubs on the ground plane produce lower frequency resonance. Taper feed line method has been used to achieve Ultra Wide Band. The final antenna results are compared by FEM and TDM techniques using HFSS and CST microwave studio 2011 simulation softwares. The antenna is built on FR-4 low cost substrate with dielectric constant a#x03B5;r = 4.4 and loss tangent tan a#x03B4;=0.02. The substrate height is h=1.6 mm and the substrate dimensions are 120mm×60mm. Simulation results of Specific Absorption Rate (SAR) shows that antenna has 1.44 W/Kg and 2.65 W/Kg for GSM 900 and GSM 1800. The antenna has high gain between 2-6.5 dBi with Omni directional radiation pattern. The antenna results are compared with other pervious researches.
11 citations
TL;DR: In this article, a dual-band planar inverted-F antenna (PIFA) is proposed for cellular phone. And the ground plane of conventional PIFA is modified using a double negative (DNG) metamaterial array.
Abstract: In this paper, a metamaterial embedded planar inverted-F antenna (PIFA) is proposed for cellular phone. A dual band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of conventional PIFA is modified using a double negative (DNG) metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The specific absorption rate (SAR) values are calculated considering two different holding positions-cheek and tilt. The results indicate that the proposed metamaterial embedded antenna produces lower SAR in the human head compared to conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances.
10 citations
Journal Article•
TL;DR: It is found that the SAR in the head is reduced significantly for both the lower and upper global systems for mobile (GSM) frequency band.
Abstract: In this paper, a new design of cell phone body is presented to reduce the specific absorption rate (SAR) in the human head. The SAR in the human head and total absorbed power by the cell phone user are calculated along with antenna performances in terms of radiation efficiency and directivity to validate the effects of cell phone body. It is found that the SAR in the head is reduced significantly for both the lower and upper global systems for mobile (GSM) frequency band. The new mobile body provides 63.8% reduction in the SAR at 900 MHz and 69.2% reduction at 1800 MHz in comparison of without mobile cover configuration. Moreover, the mobile casing improves the radiation efficiency 6% and 7% in the lower and the upper GSM frequency band respectively.
10 citations
01 Oct 2015
TL;DR: In this article, a tri-bandpass frequency selective surface (FSS) was applied on the coating of ESG for GSM 900/1800/1900 MHz, UMTS 2100 MHz frequency bands and 5G technology.
Abstract: The application of energy saving glass (ESG) is becoming a popular trend in future energy smart buildings. However, the ESG attenuates useful signals which are necessary for the communication systems owing to its coating. To solve this problem, this paper presents a Tri-bandpass frequency selective surface (FSS) on the coating of ESG for GSM 900/1800/1900 MHz, UMTS 2100 MHz frequency bands and 5G technology. And −3dB bandwidth covers 833MHz–1009MHz, 1842MHz–2200MHz and 3420MHz–4300MHz. A stable frequency response has been achieved with increasing incident angles from 0° to 45°, for both TE and TM polarizations.
9 citations
01 Nov 2015
TL;DR: This paper presents the design of an efficient yet simple RFEH module that consists of a slot antenna with circular polarization and bridge rectifier, and the measured results for the prototype in the laboratory environment are presented.
Abstract: The energy harvesting techniques form an encouraging alternative to existing energy resources The increased use of mobile phones and installation of cell phone towers have made the availability of free radio frequency (RF) energy near the transmission towers and in the ambient environment Due to the abundance of RF energy, the RF energy harvesting (RFEH) is found as an attractive possibility The harvested power may be stored to power sensor networks and also used for recharging the batteries of wireless devices like mobile phones However, there are challenges in designing the RFEH module ie rectenna, which consists of antenna, appropriate circuitry to convert the captured electromagnetic (EM) energy to DC power This paper presents the design of an efficient yet simple RFEH module The module consists of a slot antenna with circular polarization and bridge rectifier The measured results for the prototype in the laboratory environment are also presented
9 citations
TL;DR: In this article, a microstrip-fed patch antenna for cell phone applications is proposed, which is composed of slots and FR-4 dielectric substrate fed by a partial ground plane and a micro strip line.
Abstract: The aim of this article is to design a new microstrip-fed patch antenna for cell phone applications. The antenna design is composed of slots and FR-4 dielectric substrate fed by a partial ground plane and a microstrip line. The user's effects on antenna performances are also analyzed using standard SAM phantom. The specific absorption rate (SAR) values of proposed antenna are evaluated for different frequency bands considering cheek position of talk mode. The proposed antenna has an impedance bandwidth (-10 dB reflection coefficients) 100 MHz (0.87-0.97 GHz, lower band), 50 MHz (1.47-1.52 GHz, middle band), and 150 MHz (1.78-1.93 GHz, upper band), which can cover GSM 900 MHz, GPS 1,500 MHz, DCS 1,800 MHz, PCS 1,900 MHz, and GSM 1,900 MHz bands. Moreover, the proposed antenna produces lower SAR values in the human head than that of a dipole and helical antenna.
9 citations
TL;DR: Results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA, and the modified antenna substrate leads to slight improvement of the antenna performances.
Abstract: A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances.
TL;DR: In this paper, a dual band Planar Inverted F Antenna (PIFA) is presented for mobile handset applications at dual frequencies and the idea of U-shaped slot technique is introduced into the basic rectangular patch antenna for higher GSM frequency.
Abstract: In this paper dual band Planar Inverted F Antenna (PIFA) is presented for mobile handset applications at dual frequencies. PIFA is a flat structure, simple and easy to fabricate. The idea of U-shaped slot technique is introduced into the basic rectangular patch antenna for higher GSM frequency. The impedance bandwidth covers GSM 900 and GSM 1900 bands. The PIFA covers a bandwidth of 31.9MHz (0.88-0.911GHz) or about 3.5% with respect to the resonance frequency at 0.89GHz. For the higher resonant mode the impedance bandwidth is 112.7MHz (1.873-1.985GHz) or about 5.83% with respect to resonance frequency of 1.93 GHz. The PIFA has a gain of 2.59dB and 5.12dB at lower and higher resonating frequencies respectively. PIFA is analyzed using High Frequency Structure Simulator (HFSS).
Patent•
02 Dec 2015
TL;DR: In this paper, the authors proposed a method for optimizing CSFB frequency point configuration based on measurement report data, and the method includes the steps of extracting and collecting GSM RSSI and RSRP data in a measurement report reported periodically by a terminal, and calculating a score of coefficient linear weighting of each frequency point; and performing optimizing configuration of fallback frequency points of CSFB at an LTE side according to the calculated weighting scores of frequent points of a BCCH in sequence from high to low.
Abstract: The invention discloses a method for optimizing CSFB frequency point configuration based on measurement report data, and the method includes the steps of: (1) extracting and collecting GSM RSSI and RSRP data in a measurement report reported periodically by a terminal; (2) based on average RSRP of an LTE serving cell and an MR sampling proportion, performing linear coefficient weighted average processing on GSM RSSI data collected in each sector, and calculating a score of coefficient linear weighting of each frequency point; and (3) performing optimizing configuration of fallback frequency points of CSFB at an LTE side according to the calculated weighting scores of frequent points of a BCCH in sequence from high to low. Since frequency points obtained through optimizing preprocessing and screening are GSM frequency points with favorable signals, fallback quality of CSFB is high. The adopted GSM RSSI data are reported in a defined sampling period by the mobile terminal and a base station primary device, and can be obtained without a drive test, thereby reducing the burden of network optimization personnel.
22 Jun 2015
TL;DR: It can be observed that the impedance bandwidth of the proposed antenna covers the operated bandwidths of the commercial wireless communication systems, such as GSM 900, DCS, IMT-2000, UMTS, WLAN, LTE 2300, and LTE 2500.
Abstract: In this work, a new coplanar-waveguide (CPW)-fed monopole antenna with dual-band operation is proposed. The antenna is composed of a meandered monopole, an extended conductor line, and asymmetrical ground planes. Tuning geometrical structure of the ground plane of the CPW feeding structure excites additional resonant frequency bands, and thus enhances the impedance bandwidth. The measured impedance bandwidths, which is defined by −6 dB reflection coefficient, are 186 MHz (863 – 1049 MHz, 19.4%) at the lower resonant mode and 1320 MHz (1490 – 2810 MHz, 61.3%) at the upper mode. It can be observed that the impedance bandwidth of the proposed antenna covers the operated bandwidths of the commercial wireless communication systems, such as GSM 900, DCS, IMT-2000, UMTS, WLAN, LTE 2300, and LTE 2500.
01 Jan 2015
TL;DR: In this article, a 5 x 5 metamaterial array split ring resonator is introduced onto a C-shaped rectangular patch antenna with a defective ground plane, which was designed to operate at the downlink radio frequency band of GSM 900 with a pair of bevel shaped structure and a horizontal slot on top.
Abstract: In this work, a 5 x 5 metamaterial array split ring resonator is introduced onto a C -shaped rectangular patch antenna with a defective ground plane. The patch antenna was designed to operate at the downlink radio frequency band of GSM 900 with a pair of bevel shaped structure and a horizontal slot on top which was closely put at the center of the patch. The objective of this paper is to investigate the effect of metamaterial and the orientation of DSRRs with strip lines behind on the characteristics of patch antenna keeping in view of maintaining the bandwidth, return loss and ameliorating in gain. The results indicates that the amelioration in impedance bandwidth was 23.33% (77 MHz), gain of 44.4% (0.993 dB) and increase in return loss of 19% (6.71 dB ) when compared to the conventional patch antenna.
19 Jul 2015
TL;DR: A technique for reducing the Specified Absorption Rate (SAR) for mobile applications has been investigated for a PIFA designed to cover the GSM 850MHz, GSM 900 MHz, DCS 1800 MHz, PCS 1900 MHz, UMTS 2100 MHz, as well as most of the LTE bands.
Abstract: Mobile handsets have seen major design improvement in recent years, but mitigating the hazardous effects of radiation still remains a challenging issue. In this study, a technique for reducing the Specified Absorption Rate (SAR) for mobile applications has been investigated for a PIFA designed to cover the GSM 850MHz, GSM 900 MHz, DCS 1800 MHz, PCS 1900 MHz, UMTS 2100 MHz, as well as most of the LTE bands.
01 Dec 2015
TL;DR: In this article, a modified fractal sierpinski patch antenna suitable for multiband wireless application is proposed, where various heights of a triangle component are compared to achieve the desired resonant frequencies and then a coplanar wave guide feed is used to achieve more multiband resonant frequency within 0-7 GHz frequency range.
Abstract: In this paper, a modified fractal sierpinski patch antenna suitable for multiband wireless application is proposed. Various heights of a triangle component in sierpinski antenna are compared to achieve the desired resonant frequencies and then a coplanar wave guide feed is used to achieve more multiband resonant frequencies within 0-7 GHz frequency range. Return loss characteristics suggest that the antenna is suitable for WLAN, Wimax and also GSM bands for VSWR<2. Bandwidth measurement based on VSWR=2 for 900 MHz is 245 MHz, at 2.4 GHz is 620 MHz, at 3.3 GHz is 1020 MHz , and for 5.8 GHz is 400 MHz.
01 Feb 2015
TL;DR: In this paper, a critical analysis of various Frequency Selective Surface (FSS) structures like square, hexagonal and circular has been presented, which can be used to obtain a dual pass band for GSM 900 and 1800 MHz frequency.
Abstract: A critical analysis of various Frequency Selective Surface (FSS) structures like square, hexagonal and circular has been presented in this paper, which can be used to obtain a dual pass band for GSM 900 & 1800 MHz frequency. This analysis can be used to construct the FSSs for the better performance of mobile communication where energy efficient panes are used to isolate the area by restricting free passage of radiating waves, working as carriers of energy. The aperture type FSS allows the transmission of selected band frequencies. The simulation results provide an insight about the performance of these FSSs. The substrate used is teflon (er =2.1) and it is being considered as per the need of lesser thickness (1 mm) and providing flexibility so as to be incorporated over any individual surface.
16 Apr 2015
TL;DR: A reconfigurable planar antenna that can operate in the ISM band of 2400 MHz and in the mobile GSM telephony band of 1850 MHz that is also in accordance to required parameters to be used for Cognitive Radio applications is described.
Abstract: In this paper we describe the analysis and design of a reconfigurable planar antenna that can operate in the ISM band of 2400 MHz and in the mobile GSM telephony band of 1850 MHz, that is also in accordance to required parameters to be used for Cognitive Radio applications. The antenna was designed as a plane square spiral using microstrip technology and the reconfigurability was made with an inductor.
01 Nov 2015
TL;DR: In this article, a dual-band antenna for machine-to-machine (M2M) applications in ISM and GSM bands is presented, with good efficiency and gain across the frequency bands.
Abstract: A dual band antenna for machine-to-machine applications in ISM and GSM bands is presented. The antenna is compact and operates at 409–442 MHz and 800–1224 MHz, with good efficiency and gain across the frequency bands. A parametric investigation of key geometrical parameters is reported.
01 Jan 2015
TL;DR: In this paper, a triple band planar inverted-F antenna (PIFA) is proposed to operate at three operating frequencies of GSM bands (900 MHz and 1800 MHz), and Bluetooth band (2400 MHz).
Abstract: Recently, the demand for wireless devices that support multi-band frequency has increased. In fact, employing single-band antennas leads to large space requirement in handheld devices. Therefore, due to the space constraints in mobile devices, an antenna which will cover multiple bands of frequencies will be the best solution in order to allow more space in the mobile devices. The integration of such technology in mobile communication system has led to a great demand in developing small size antenna with multi-band operation that is able to operate in the required system. In this paper, a triple band planar inverted-F antenna (PIFA) is proposed. The antenna has been measured and found to operate at three operating frequencies of GSM bands (900 MHz and 1800 MHz), and Bluetooth band (2400 MHz). A dual L-shaped slot was used on the patch to obtain the triple-band resonant frequencies. Performance of the antenna has examined and results have shown that the proposed antenna can successfully cover frequencies 900 MHz, 1800 MHz and 2400 MHz.
Patent•
25 Nov 2015
TL;DR: In this article, the authors proposed a wireless communication anti-interference method for network switching in presence of signal interference and realized normal transmission of data, which consists of the following steps: providing wireless communication module, a GSM frequency range network and an antiinterference frequency-range network; detecting interference; switching the networks; and recovering the networks.
Abstract: The invention provides a wireless communication anti-interference method. The method comprises the following steps: providing a wireless communication module, a GSM frequency range network and an anti-interference frequency range network; detecting interference; switching the networks; and recovering the networks. Compared to the prior art, the wireless communication anti-interference method provided by the invention can perform network switching in presence of signal interference and realizes normal transmission of data. Besides, the invention also provides a wireless communication module.
Patent•
01 Apr 2015
TL;DR: In this article, a mobile positioning system consisting of a wireless communication module, an application processor and a GPS assembly is presented, where the wireless communication modules and the GPS assembly are connected to the application processor.
Abstract: The invention provides a mobile positioning system which comprises a wireless communication module, an application processor and a GPS assembly, wherein the wireless communication module and the GPS assembly are connected to the application processor; one of GPIO (general purpose input/output) ports of the wireless communication module is defined as a GPS control port and the wireless communication module is used for outputting a GPS control signal to the application processor by virtue of the GPS control port when the wireless communication module works in a GSM mode and is in a GSM transmitting power state; the application processor is used for closing the GPS assembly or stopping GPS data reception when receiving the GPS control signal from the GPS control port of the wireless communication module. The invention further provides a mobile positioning anti-inference method based on the mobile positioning system.
TL;DR: A low power high linearity amplitude modulation path using a current reusing technique is proposed for a quad band GSM/EDGE polar transmitter and demonstrates the output power and output noise floor level at 20 MHz offset frequency of at GSM mode.
Abstract: A low power high linearity amplitude modulation path using a current reusing technique is proposed for a quad band GSM/EDGE polar transmitter. In order to reduce the current consumption and silicon area, the function of a programmable gain amplifier, AM-PM combiner and driver amplifier is realized as one stacked circuit structure. The proposed amplitude modulator is implemented in a 65nm CMOS technology and demonstrates the output power of 4 dBm and -172 dBc/Hz output noise floor level at 20 MHz offset frequency of at GSM mode. Also, the 3rd-order InterModulation Distortion (IMD3) level is below -40 dBc at all GSM/EDGE bands. The total 42 dB gain control range with a 1 dB step is achieved using a current cancelling technique without its other performance degradation. The total current consumption is 13 mA at GSM mode and 40 mA when it operates at EDGE operation from a 2.8 V supply voltage.
Proceedings Article•
13 May 2015TL;DR: In this article, a design for a broadband, light weight and low cost smart shield frequency selective device is proposed, which consists of a dual layer printed circuit board patch array and is capable of absorbing WLAN signals in the frequency range around 5.5 GHz, whilst allowing almost unitary transmission outside this range.
Abstract: In this paper a design for a broadband, light weight and low cost smart shield frequency selective device is proposed. The device consists of a dual layer printed circuit board patch array and is capable of absorbing WLAN signals in the frequency range around 5.5 GHz, whilst allowing almost unitary transmission outside this range, for example the GSM frequency band ranging from 0.8 to 2.1 GHz. Therefore it can effectively be utilized in telecommunications, radomes and as a shielding structure in electronic devices.
26 Mar 2015
TL;DR: The results show that Bertoni model is better for predicting the path loss in tall buildings than Cost-walfisch Ikegami model or Okumura Hata model for propagation characteristics of GSM systems.
Abstract: As degradation of signal issue become critical in today's communication medium. So prediction of correct path loss is important for GSM radio network planning to estimate network interference level and cell planning deployment accurately. GSM (Global System Mobile Communications) signal throughput and coverage range is one of the most important factors that will impair the quality of broadband wireless systems [2]. The study focused on shadowing effect in urban (combination of green vegetation and high raised buildings) terrains for propagation characteristics of GSM systems. A GSM frequency 950 MHz used for this experiment in a typical urban terrains. The measurement results compared with Cost-walfisch Ikegami model, Okumura Hata model and Bertoni-walfisch model. Finally, the results show that Bertoni model is better for predicting the path loss in tall buildings. The results are obtained using MatLab simulation software.
Patent•
29 Apr 2015
TL;DR: In this paper, the utility model provides a device for automatically turning down the volume during a mobile phone call inside a vehicle, and when the phone call is finished, the volume is restored.
Abstract: The utility model provides a device for automatically turning down the volume during a mobile phone call inside a vehicle. If a phone call is detected inside the vehicle, the volume of vehicle sound equipment is automatically turned down, and when the phone call is finished, the volume is restored. Therefore, the defect that hand-operated muting operation of the driver causes distractions is overcome. A signal induction module is composed of an antenna, a frequency divider, a mobile phone signal processor and a frequency modulator. A processing module includes a single-chip microcomputer. An execution module includes a drive circuit and a vehicle sound equipment circuit. A mobile phone signal is divided by the frequency divider into four paths of signals: one path is subjected to TD-SCDMA processing and TD-SCDMA frequency modulation; one path is subjected to WCDMA processing and WCDMA frequency modulation; one path is subjected to CDMA2000 processing and CDMA2000 frequency modulation; and one path is subjected to GSM processing and GSM frequency modulation. The four paths of signals are integrated for digital processing and output. The obtained signal passes through a signal amplification circuit and the drive circuit, and is output to a sound equipment volume adjusting circuit.
01 Dec 2015
TL;DR: A tri-band epsilon-near-zero (ENZ) substrate integrated waveguide (SIW) based microwave sensor for microwave material testing at global system for mobile communications (GSM) bands is presented in this article.
Abstract: This paper presents a novel tri-band epsilon-near-zero (ENZ) substrate integrated waveguide (SIW) based microwave sensor for microwave material testing at global system for mobile communications (GSM) bands. The prototype RF sensor is designed, simulated, and tested for the microwave characterization of materials in 3G and 4G frequency bands. The proposed design provides a substantial reduction in the sensor size, and facilitates complex permittivity measurement at multiple frequencies with reasonable sensitivity as compared to the conventional SIW based sensors. The device is fabricated using multiple layers of FR4 substrate, and the RF signal is coupled using SMA connectors which is then tested for various reference samples. The measured data are found to be in good agreement with their reference values thus validating the proposed design methodology.
Patent•
07 Oct 2015
TL;DR: In this article, a cascade radio frequency power amplifier used for GSM/DCS comprises a GSM frequency band cascade power amplification circuit composed of a first radio frequency transistor and a second radio frequency transistors, and a DCS frequency band cascading power amplifier composed of an additional third and a fourth transistor, where the four transistors adopt GaAs E/D pHEMT technology.
Abstract: The invention discloses a cascade radio-frequency power amplifier used for GSM/DCS The cascade radio-frequency power amplifier used for the GSM/DCS comprises a GSM frequency band cascade power amplification circuit composed of a first radio frequency transistor and a second radio frequency transistor and a DCS frequency band cascade power amplification circuit composed of a third radio frequency transistor and a fourth radio frequency transistor, wherein the GSM frequency band cascade power amplification circuit and the DCS frequency band cascade power amplification circuit share a common-gate grid decoupling capacitor; a first biasing circuit and a second biasing circuit of the GSM frequency band cascade power amplification circuit and a third biasing circuit and a fourth biasing circuit of the DCS frequency band cascade power amplification circuit are connected with a power control unit, and the power control unit is provided with at least one control signal end used for adjusting the output biasing voltage of the four biasing circuits The four transistors adopt GaAs E/D pHEMT technology, and the advantages of high performance and low cost are achieved