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Radio and Wireless Symposium (RWS), 2014 IEEE

Date 19-23 Jan. 2014

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Displaying Results 1 - 25 of 94
  • IndexSCR

    Page(s): 1
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    Freely Available from IEEE
  • Final program

    Page(s): 1 - 24
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    Freely Available from IEEE
  • Adaptive RF canceller for transmit-receive isolation improvement

    Page(s): 172 - 174
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (539 KB) |  | HTML iconHTML  

    For effective operation, Simultaneous Transmit And Receive (STAR) systems require high isolation between the transmitted signals and the receiver input, the absence of which can lead to the saturation of a receiver's front end. This paper presents an adaptive RF canceller used to improve isolation. The canceller is configured as an RF tapped delay line with four taps, each with independent amplitude and phase weights that are tuned by a Dithered Linear Search algorithm. This canceller produces 30 dB of signal cancellation over a 30 MHz bandwidth centered at 2.45 GHz in an isolated environment. When combined with a high-isolation antenna, an overall STAR system isolation of 90 dB is achieved, while also maintaining omni-directional transmit and receive antenna patterns. View full abstract»

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  • A 12.1 mW 50∼67 GHz up-conversion mixer with 6 dB conversion gain and 30.7 dB LO-RF isolation in 90 nm CMOS

    Page(s): 202 - 204
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB) |  | HTML iconHTML  

    A 50~67 GHz double-balanced mixer for direct up-conversion using standard 90 nm CMOS technology is reported. The up-conversion mixer comprises an enhanced double-balanced Gilbert cell with current injection for power consumption reduction, and negative resistance compensation for conversion gain (CG) enhancement, a parallel and differential IF transconductance stage for bandwidth and linearity enhancement, a Marchand balun for converting the single LO input signal to differential signal, and another Marchand balun for converting the differential RF output signal to single signal. The mixer consumes 12.1 mW and achieves IF-port input return loss of -12.8 dB at 0.1 GHz, LO-port input return loss of -9.5 ~ -11.4 dB and RF-port input return loss of -10.7 ~ -12.5 dB for frequencies 57~64 GHz. At IF of 0.1 GHz, the mixer achieves CG of 3.1~6 dB and LO-RF isolation of 26.4~30.7 dB for RF of 50~67 GHz. The corresponding 3-dB bandwidth of RF is larger than 17 GHz (the measurement range of 50~67 GHz). To the authors' knowledge, the CG and power consumption are one of the best results ever reported for a 60 GHz CMOS/BiCMOS up-conversion mixer. View full abstract»

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  • A 5.5 GHz low-power PLL using 0.18-µm CMOS technology

    Page(s): 205 - 207
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (218 KB) |  | HTML iconHTML  

    This paper presents a fully-integrated 5.5 GHz low-power consumption phase-locked loop (PLL) on standard 0.18-μm CMOS process. Utilizing the transformer feedback VCO and high speed true single phase clock (TSPC) divider, the 5.5 GHz PLL achieves low power consumption of 9.23 mW. In addition, a rail-to-rail buffer amplifier is incorporated between the VCO and TSPC divider chain to provide full voltage swing for TSPC input. The measured phase noises are -85 dBc/Hz and -116.6 dBc/Hz at 1 MHz and 10 MHz frequency offsets, respectively. View full abstract»

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  • A 9.96 mW 3.24±0.5 dB NF 1.9∼22.5 GHz wideband low-noise amplifier using 90 nm CMOS technology

    Page(s): 208 - 210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    A 1.9~22.5 GHz wideband LNA based on the current-reused cascade configuration in 90 nm CMOS is reported. The wideband input-impedance matching was achieved by taking advantage of the resistive shunt-shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel RLC branches, i.e., a second-order wideband BPF. The wideband output matching was also achieved by making the output network equivalent to a second-order wideband BPF. Theoretical analysis shows that both the frequency response of input matching and NF can be described by second-order functions with quality factors as parameters. The LNA dissipates 9.96 mW and achieves low and flat NF of 3.24±0.5 dB and high and flat S21 of 12.02±1.5 dB for frequencies 1.9~22.5 GHz. The corresponding FOM is 7.44 GHz/mW, one of the highest FOMs ever reported for an LNA with bandwidth around 20 GHz. View full abstract»

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  • A simple closed-form analysis of clapp oscillator output power using a novel quasi-linear transistor model

    Page(s): 88 - 90
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (825 KB) |  | HTML iconHTML  

    Clapp oscillator output power is analyzed in closed form using a novel quasi-linear transistor model where the transadmittance is a function of base-to-emitter voltage amplitude. The function is easy to invert which makes the analysis considerably simpler than any other previously published closed-form approach. The proposed technique is validated by transistor and oscillator measurements and with harmonic balance simulation at 100 MHz. View full abstract»

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  • Investigating the effect of grounding GPS antennas on their radiation properties on vehicular platforms

    Page(s): 28 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (357 KB) |  | HTML iconHTML  

    The global positioning system (GPS) has become a standard navigation tool in modern vehicular platforms. The location of the GPS antenna has a direct impact on the overall navigation system performance. In this work, we investigate the effect of shorting the GPS antenna placed on the front windshield of a vehicle to its rooftop GND plane. It is shown that such a connection will improve the gain of the antenna by several dBs. View full abstract»

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  • A CPW fed rectangular slot antenna for wideband circular polarization

    Page(s): 94 - 96
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    A CPW excited rectangular slot antenna for circular polarization is presented. The feed line is terminated on a circular disc having a slant rectangular slit. Inverted L-shape strips are attached to the ground plane and protrude into the rectangular slot. The measured impedance bandwidth achieved by the antenna is 124% from 2.4 GHz to 10.2 GHz The measured bandwidth of circular polarization with axial ratio <; 3 dB is 40% (simulated - 48%) from 4.75 GHz to 7.1 GHz. The antenna is compact in size, has good radiation patterns and is expected to be useful for portable communication devices operating in the above mentioned range with requirement of circular polarization. View full abstract»

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  • Symmetric coupled composite right-/left-handed transmission line with dual-mode balanced filter characteristics

    Page(s): 151 - 153
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB) |  | HTML iconHTML  

    In this paper, a symmetric coupled composite right-/left-handed transmission line (CRLH-TL) with dual-mode balanced filter characteristics is proposed. Unlike the other symmetric structures, this configuration has the ability to operate under both common- and differential-mode excitation. This ability is achieved by providing a physical short circuit by means of ground vias at the center of each unit-cell along the symmetry plane of the structure. In this study, we implemented a dual-mode balanced filter on the basis of the fact that CRLH unit-cells can be operated under both common- and differential-mode excitation. To validate this ability, a five-cell four port symmetric coupled CRLH-TL is simulated, fabricated, and its performance is measured. The obtained results are in good agreement with the simulation results under both common- and differential-mode excitation. View full abstract»

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  • Prototyping and performance evaluation of TDD-based 2×2 MIMO-OFDM transceiver

    Page(s): 43 - 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    We have been developing a new wireless link that enables quick transmission of file-based video resources for news programmes. Since the transmission distance we assume ranges widely from less than 1 km to as far as 50 km, it is necessary to have efficient transmission timing control in duplex communication based on TDD. In order to enhance the transmission capacity in line-of-sight environments, it is useful to introduce a MIMO technique that exploits dual-polarized antennas and a multilevel modulation scheme such as 128 QAM and 256 QAM. In this paper, we describe the prototype TDD-based 2×2 MIMO-OFDM transceiver and its performance evaluation in wired and radio transmission experiments. View full abstract»

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  • Tunable liquid-crystal millimeter-wave bandpass filter using periodical structure

    Page(s): 163 - 165
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (542 KB) |  | HTML iconHTML  

    For the first time, a tunable liquid crystal (LC) bandpass filter using a microstrip periodical structure for applications at millimeter-waves is presented. In the LC default state, it operates at 49 GHz with about 20% fractional bandwidth (9 GHz). The filter tunability range is 3.2 GHz over bias voltages 0 to 10 V and its insertion loss is about 4.7 dB. Dimensions of the filter can be scaled to increase its operating frequency to 77 GHz and hence, is a promising component for 60 GHz systems. View full abstract»

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  • A 1.2V, 2.7mA receiver front-end for bluetooth low energy applications

    Page(s): 37 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    This paper presents a fully integrated bluetooth low energy (BTLE) receiver front-end implemented in 0.13 um CMOS including the low noise amplifier (LNA), mixer and a variable bandwidth complex bandpass filter. The measured current consumption of the complete front-end is only 2.7 mA at 1.2 V. The designed front-end provides a voltage gain of 40 dB, a noise figure of 11 dB and a IIP3 of -21.2 dBm. The receiver front-end supports also the standard mode of bluetooth (BT) which can be easily achieved by adjusting the bandwidth of the baseband filter. Moreover, circuit techniques have been implemented in the RF front-end to improve the overall production yield and minimize production cost. View full abstract»

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  • Energy efficiency of cooperative cognitive radio network with outage constraints

    Page(s): 175 - 177
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (230 KB) |  | HTML iconHTML  

    The power allocation in decode and forward (DF) relaying for cooperative cognitive radio network (CCRN) with an objective of maximizing energy efficiency (EE) is a constraint nonlinear non-convex fractional programming problem (CNNFPP). The optimization needs to satisfy the primary users interference constraints and secondary users outage constraints. We proposed the optimal power allocation in DF relaying by transforming the CNNFPP power allocation problem into a concave fractional program. We also present numerical results to demonstrate the effect of different network parameters on the EE of CCRN. View full abstract»

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  • Planar antipodal linearly tapered slot antenna using grounded coplanar waveguide-to-substrate integrated waveguide transition for passive millimeter-wave imaging

    Page(s): 211 - 213
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB) |  | HTML iconHTML  

    In this work, a novel antipodal linearly tapered slot antenna (ALTSA) with two types of grounded coplanar waveguide (GCPW)-to-substrate integrated waveguide (SIW) transitions are proposed and demonstrated. The antenna is well designed for using as a feed antenna in the focal plane array (FPA) imaging system. PCB technology is used to fabricate the SIW antenna in a single layer structure. Good agreement was obtained between the simulation and measurement results. The return loss of the proposed antenna can achieve below -13dB at Ka-band, meanwhile, the E-plane side lobe is almost 15dB down. When placed on the focal plane of a reflector antenna, its side lobe dropped to 40dB down, which shows its high suitability for passive millimeter-wave (PMMW) FPA imaging system. View full abstract»

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  • A wideband phase modulation technique adopting Fractional-N Direct Digital Frequency Synthesizer

    Page(s): 214 - 216
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (443 KB) |  | HTML iconHTML  

    In this paper, an open-loop phase modulator, called Fractional-N Direct Digital Frequency Synthesizer (DDFS), for polar transmitter is proposed to resolve the limited bandwidth problem occurred in the traditional phase-locked loop (PLL)-based phase modulator. Besides, an effective noise shaping quantization method is taken into account to attenuate the fractional-spurs introduced by Fractional-N DDFS. The worst case RMS EVM per burst of the modulator is 0.32% when performing 10-Mbps 16PSK. View full abstract»

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  • SDR for SRD: ADC specifications for reconfigurable gateways in urban sensor networks

    Page(s): 178 - 180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (222 KB) |  | HTML iconHTML  

    Short Range Devices (SRD) are increasingly employed in urban sensor networks using different communication protocols. That becomes a key problem in the gateway design, since its cost and energy consumption increase with the number of implemented technologies. This cost and energy can be reduced by using a reconfigurable gateway to perform the biggest part of signal processing digitally, as it is done in Software-Defined Radio (SDR). As several received signals should be simultaneously digitized, Analog-to-Digital Converter (ADC) must be able to treat the whole frequency band used by SRD, with a high enough resolution to properly demodulate the signals. This paper describes what the ADC's constraints are and how to dimension an ADC in SDR for SRD. An example based on the SmartSantander deployment shows that an ADC resolution of 21 bits is required to properly demodulate the data. View full abstract»

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  • Full duplex prototype of OFDM on GNURadio and USRPs

    Page(s): 217 - 219
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (245 KB) |  | HTML iconHTML  

    Full-duplex is a technology in telecommunication domain that can perform transmitting and receiving at the same time and in the same frequency band. The major obstacle of full-duplex is the self-interference (SI). Some previous works have focused on the SI cancellation in radio frequency (RF), and generally on a narrowband signal model. We have implemented a full-duplex prototype with orthogonal frequency-division multiplexing (OFDM) technology on GNURadio and Universal Software Radio Peripherals (USRP). We focus on the baseband, namely the digital part of the SI cancellation. Our testbed can achieve a digital cancellation of 27dB. After the cancellation, the signal of interest can achieve a bit error rate (BER) in the scale of 10-5 at 4 meters, which is very close to the performance of half-duplex. This is, to our knowledge, the first full duplex implementation for OFDM technology. View full abstract»

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  • Design of low phase-noise voltage-controlled oscillator using tunable evanescent-mode cavity

    Page(s): 82 - 84
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    In this paper, a low phase-noise voltage-controlled oscillator using tunable evanescent-mode cavity is designed, fabricated, and measured. The oscillator is tuned by lumped element varactors placed on the top surface of a substrate-integrated evanescent-mode cavity. The tuning range of the oscillator is 783.6-976.8 MHz with peak output power of 6.97 dBm at 943.2 MHz. Over the tuning frequency the oscillator has a phase noise from -103.8 to -119.4 dBc/Hz at 100 kHz offset frequency and from -141.8 to -152.3 dBc/Hz at 1 MHz offset frequency. The resonator is compatible with RF MEMS tuner to yield a higher resonator Q and better phase noise performance. View full abstract»

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  • A 21.1 mW 6.2 dB NF 77∼81 GHz CMOS low-noise amplifier with 13.5±0.5 dB S21 and excellent input and output matching for automotive radars

    Page(s): 73 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (139 KB) |  | HTML iconHTML  

    A low power and wideband three-stage millimeter-wave (MMW) low-noise amplifier (LNA) using standard 90 nm CMOS technology is reported. T-network (or π-match) is utilized to achieve simultaneously wideband input and output impedance matching, wideband power gain (S21) and wideband NF at W-band. The LNA consumes 21.1 mW, achieving S11 better than -10 dB for frequencies 62.3~82.4 GHz, S22 better than -10 dB for frequencies 62.8~84.6 GHz, S12 better than -29 dB for frequencies 72~84 GHz, and group delay variation smaller than ±6.5 ps for frequencies 70~90 GHz. Additionally, high and flat S21 of 13.1±1.5 dB is achieved for frequencies 72~84 GHz, which means the corresponding 3-dB bandwidth is 12 GHz. Furthermore, the LNA achieves minimum noise figure (NF) of 6.2 dB at 78 GHz and NF of 6.8±0.6 dB for frequencies 75~82 GHz, one of the best NF results ever reported for a W-band CMOS LNA. View full abstract»

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  • A tunable directional coupler with a wide tuning range of coupling ratios

    Page(s): 154 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (413 KB) |  | HTML iconHTML  

    A tunable microwave 90-degree directional coupler with a wide tuning range of coupling ratios is introduced in this paper. The architecture of this device is designed based on a fully symmetrical structure. Two varactor diodes loaded to the side of the device are used as the tuning elements. With different biasing voltage, the output power ratio between the two output ports (Port 2 and Port 3) can be easily tuned. During the tuning, very good isolation and low return loss are always kept. In the theoretical discussion, the general design equations are presented. Also, a sample circuit working at 1 GHz was made and tested to verify the design theory. The measurement results of the prototype show a good agreement with the design theory. View full abstract»

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  • Design of rectenna array panel taking into account mutual coupling for RF energy harvesting

    Page(s): 61 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (530 KB) |  | HTML iconHTML  

    A study of a rectenna (rectifying anntena) array on a 1×1-m substrate for RF energy harvesting is presented. Square loop antennas are laid out on the given substrate size assuming to harvest 500-MHz Digital TV radio waves. The optimum number of elements is determined from the obtainable DC power and its angle characteristics taking into account mutual coupling between antenna elements and the non-linear RF-to-DC conversion efficiency of the rectifier. Mutual coupling effects can be exploited to control the angle characteristics to some extent. In this particular consideration, a 4×3 rectenna array was optimum in the harvesting of 500-MHz radio waves from a broad angle range in the horizontal dimension. View full abstract»

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  • Performance analysis of cognitive radio networks over к-μ fading channel with noise uncertainty

    Page(s): 106 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (194 KB) |  | HTML iconHTML  

    In order to be able to perform a Spectrum Sensing in a reliably manner we must take in consideration a physical fading model which will fit with the reality presented. In this work we analyze the energy detection characteristics over a generalized fading channel, modeled by the κ-μ distribution. Admitting the noise power estimation error, the worst-case of the probabilities of miss detection and false-alarm, due to the noise uncertainty, are derived under the spectrum utilization constraint. An optimal threshold selection is presented in order to allow the energy detector to operate in regions of low SNR. Field measurements are used to investigate in practice the usefulness of the κ-μ fading channel in cooperative spectrum sensing scenarios. Comparisons are performed against Rice fading model where it is possible to notice a great advantage in using the κ-μ distribution to describe the fading channel. View full abstract»

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  • Nonlinear distortion suppression scheme employing transmit power control for MU-MIMO-OFDM systems

    Page(s): 46 - 48
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (884 KB) |  | HTML iconHTML  

    MU-MIMO-OFDM is an effective technique to achieve high capacity and reliable wireless communications systems because both the robustness against multipath fading and the high spectrum efficiency can be effectively achieved by the combination of OFDM with MU-MIMO. However, MU-MIMO-OFDM significantly suffers from the nonlinear distortion which is a main drawback of OFDM. In this paper, we propose nonlinear distortion suppression scheme employing transmit power control for MU-MIMO-OFDM. The main feature of the proposed scheme is to apply the deterministic transmit power control to MU-MIMO-OFDM without any destruction of the space orthogonality. The effectiveness of the proposed scheme is demonstrated in comparison with the traditional MU-MIMO-OFDM over the nonlinear fading channels. View full abstract»

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  • Indoor localization based on feed-forward Neural Networks and CIR fingerprinting techniques

    Page(s): 271 - 273
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    Many solutions to accurate localization in indoor environments are based on the combination of Channel Impulse Response (CIR), as fingerprinting, and Neural Networks (NN) technique. Suitable there is no theory to indicate the neural network structure for a given problem. It must be done only experimentally. Then, this paper aims to identify the neural network structure and the accompanied algorithm which are suitable for indoor localization. For this purpose, different NN structures accompanied with various algorithms are compared and discussed in order to identify the most appropriate. View full abstract»

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