The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Takehiko Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • Bandwidth Dependence of Ultra-Wideband Radio Propagation in Closed and Semi-Closed Spaces
    2018 International Workshop on Computing Electromagnetics and Machine Intelligence (CEMi), 2018
    Co-Authors: Ayumu Minegishi, Miyuki Hirose, Takehiko Kobayashi
    Abstract:

    This paper presents the Bandwidth dependence of ultra-wideband radio propagation within a shield box, a conductive box with three 200 mm circular apertures, a small scientific satellite, and a ticket vending machine. Spatial distribution of propagation gains between 7.25 and 10.25 GHz inside the objects were measured. No appreciable differences were found in the fading depths in terms of the Occupied Bandwidth between 0.5 to 3 GHz, which are defined by the differences between the maximum and minimum gains within the spatially scanned area. Results of electromagnetic simulaton agreed well with those of the experiment.

  • Measurements and Characterization of Ultra Wideband Propagation Channels in a Passenger-Car Compartment*This work was supported in part by the Research Institute for Science and Technology, Tokyo Denki University, under the grant Zb05-01, and in part
    IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences, 2006
    Co-Authors: Takehiko Kobayashi
    Abstract:

    Ultra wideband (UWB) signal propagation was measured and characterized in comparison with narrowband in a passenger-car compartment, to accommodate the design of new wireless devices for the safety and comfort of passengers. Spatial distributions of UWB and narrowband path gain, delay profiles, and delay spreads within the compartment were derived from frequency-domain responses (from 3.1 to 10.6 GHz) measured with a vector network analyzer. Whereas narrowband channels resulted in a number of dead spots (deep fading points), UWB yielded none, though some frequency dispersion was inevitable. Fading depth versus Occupied Bandwidth was also derived, which indicated superiority of UWB over narrowband systems from the viewpoint of link budget. Comparison with two other environments was also made in the received energy contained in a given number of multipath components.

  • Measurements and Characterization of Ultra Wideband Propagation Channels in a Passenger-Car Compartment
    2006 IEEE Ninth International Symposium on Spread Spectrum Techniques and Applications, 2006
    Co-Authors: Takehiko Kobayashi
    Abstract:

    Ultra wideband (UWB) signal propagation was measured and characterized in comparison with narrowband in a passenger-car compartment, to accommodate a design of new wireless devices for the safety and comfort of passengers. Spatial distributions of UWB and narrowband path gain, delay profiles, and delay spreads within the compartment were derived from frequency-domain responses (from 3.1 to 10.6 GHz) measured with a vector network analyzer. Whereas narrowband channels resulted in a number of dead spots (deep fading points), UWB yielded none, though some frequency dispersion was inevitable. Fading depth versus Occupied Bandwidth was also derived, which indicated superiority of UWB over narrowband systems from the viewpoint of link budget. Comparison with two other environments was also made in the received energy contained in a given number of multipath components

T M Nguyen - One of the best experts on this subject based on the ideXlab platform.

Chengyan Ma - One of the best experts on this subject based on the ideXlab platform.

  • ISCAS - A 5.8GHz integrated CMOS transmitter for Chinese electronic toll collection system
    2013 IEEE International Symposium on Circuits and Systems (ISCAS2013), 2013
    Co-Authors: Shimao Xiao, Tianchun Ye, Xiaofeng He, Min Qian, Yunfeng Yu, Wei Huang, Chengyan Ma
    Abstract:

    A fully integrated direct up-conversion transmitter for Chinese electronic toll collection system (ETCS) is presented in a 0.18um CMOS process. Improved isolation between power amplifier (PA) and voltage-control oscillator (VCO) is achieved by configuring the VCO frequency to be 2/3 transmission frequency. A 5.8GHz mixer with an automatic amplitude control (AAC) loop is proposed to obtain better amplitude shift keying (ASK) performance. The Occupied Bandwidth of the transmitter is optimized by digital filtering. A high-linearity ASK modulator translates the base-band signal to carrier frequency and a two-stage class-A and class-AB PA is adopted to obtain sufficient efficiency and relatively high linearity. The transmitter consumes only 99mW with 1.8V supply voltage to meet the low-power demand of Chinese ETCS and carries a single-ended 3.2dBm output power. Under 1.024Mbps data rate, the eye-opening is better than 91% and the transmitter achieves -58.2dBc adjacent channel power ratio (ACPR) and 1.46MHz Occupied Bandwidth.

  • A 5.8GHz integrated CMOS transmitter for Chinese electronic toll collection system
    Proceedings - IEEE International Symposium on Circuits and Systems, 2013
    Co-Authors: Jian Shi, Shimao Xiao, Wenguang Pan, Tianchun Ye, Xiaofeng He, Min Qian, Chengyan Ma
    Abstract:

    A fully integrated direct up-conversion transmitter for Chinese electronic toll collection system (ETCS) is presented in a 0.18um CMOS process. Improved isolation between power amplifier (PA) and voltage-control oscillator (VCO) is achieved by configuring the VCO frequency to be 2/3 transmission frequency. A 5.8GHz mixer with an automatic amplitude control (AAC) loop is proposed to obtain better amplitude shift keying (ASK) performance. The Occupied Bandwidth of the transmitter is optimized by digital filtering. A high-linearity ASK modulator translates the base-band signal to carrier frequency and a two-stage class-A and class-AB PA is adopted to obtain sufficient efficiency and relatively high linearity. The transmitter consumes only 99mW with 1.8V supply voltage to meet the low-power demand of Chinese ETCS and carries a single-ended 3.2dBm output power. Under 1.024Mbps data rate, the eye-opening is better than 91% and the transmitter achieves -58.2dBc adjacent channel power ratio (ACPR) and 1.46MHz Occupied Bandwidth. © 2013 IEEE.

Xing Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Design of a directional ultra-wideband planar antenna array
    Proceedings of the 9th International Symposium on Antennas Propagation and EM Theory, 2010
    Co-Authors: Zhaohui Huang, Xing Jiang
    Abstract:

    The design of a directional ultra-wideband printed circular monopole antenna array operating in 3.1–10.6 GHz is proposed in this paper. The two elements of the array are fed by a broadband T-junction power divider. The antenna's Occupied Bandwidth of the return loss on a −10 dB level is 7.98 GHz which is from 2.74 GHz to 11.65 GHz where the octave band is 4.25. The gains are 5.25 dB at 3 GHz, 7.56 dB at 6 GHz and 8.62 dB at 9 GHz, respectively. The final size of this antenna is 28.4×67 mm2, and the thickness is 1 mm. The proposed antenna array could be easily integrated and apply to the directional long-distance terrestrial UWB communication systems effectively.

Jiang Xing - One of the best experts on this subject based on the ideXlab platform.

  • Design of Directional Ultra-Wideband Planar Antenna Array
    Journal of Microwaves, 2010
    Co-Authors: Jiang Xing
    Abstract:

    The design of a directional ultra-wideband printed circular monopole antenna array to operate in the 3.1-10.6 GHz UWB is proposed in this paper.The two printed circular monopole antennas are fed by broadband T-junction power divider.The antenna has an Occupied Bandwidth of the return loss on a -10 dB level is 7.98 GHz which is from 2.98 to 10.96 GHz,and the octave band is 3.68.The gains are 3.54 dB at 3 GHz,5.03 dB at 6 GHz and 5.67 dB at 9 GHz,respectively.The final size of this antenna is 28.4×67 mm~2,and the thickness is 1 mm.The characteristic of direction is obtained effectively,and hence the antenna can be used in the directional long-distance terrestrial broadband communications