A. Cidronali

University of Florence, Florens, Tuscany, Italy

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Publications (102)34.29 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the design of a high-power dual-band power amplifier (PA) for envelope tracking (ET) operation and its characterization in concurrent dual-band ET operation modes. The design approach relies on the specific actual signal probability distribution and the prototype was conceived for the WCDMA 3GPP DL signals. The paper discusses the impact of the ET-shaping function influence on the linearity versus mean efficiency trade-off, for both single and concurrent dual-band cases. The technique was applied to a concurrent 870 and 2140 MHz ET-PA designed around a GaN HEMT device. The ET friendly design method led to performance very close to those observed at each single band. Over a bandwidth of 100 MHz and for PAR = 6.5 dB, the measured results reported a mean DE better than 71 and 54%, with a peak power higher than 55 and 54 dBm, at the two frequency bands, respectively. When evaluated in concurrent dual-band mode with two WDCMA signals at 6.5 dB PAR each, the ET-PA exhibited an estimated average total power of 49.5 dBm with 57.1% average drain efficiency.
    International Journal of Microwave and Wireless Technologies 12/2013; 5(06). · 0.57 Impact Factor
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    ABSTRACT: This letter presents a signal probability distribution function conscious characterization technique, suitable for the optimization of envelope tracking (ET) power amplifiers. The method and its validation rely on pulsed harmonic load-pull measurements. The analytical treatment permitted to understand the impact of the peak-to-average power ratio on the load termination, and the experimental characterization revealed the sensitivity of the ET performance with respect to the load termination. The technique was applied to a GaN HEMT device at the carrier frequency of 870 MHz.
    IEEE Microwave and Wireless Components Letters 01/2013; 23(7):380-382. · 1.78 Impact Factor
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    ABSTRACT: This paper details the implementation and performance of an reconfigurable carrier leakage canceler for 5.8 GHz Dedicated Short-Range Communications. DSRC systems suffer of desensibilization because of large leakage of the carrier due to imperfect TX-RX antenna isolation. The proposed circuit, which consists of electrically tunable attenuator and a phase shifter, can be adaptively tuned to erase the leaked signal. Hardware realization is carried out based on simulation model in ADS (Advanced Design System). Measurement results indicate that the TX-to-RX isolation is improved from 35 dB to above 58 dB at center frequency, or an improvement of more than 23 dB of carrier leakage cancellation. To the author knowledge it is an unmatched result at the frequency of 5.8 GHz.
    Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International; 01/2013
  • G. Casini, A. Cidronali, G. Manes
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    ABSTRACT: This work reports the experimental evaluation of X-parameters models for the simulation of ET systems. We have extracted 2-port and 3-port X-parameters models from large signal vector measurements, for a GaAs PA with 40 dBm nominal peak power at 850 MHz. The data suggests that 3-port X-parameter model not only leads to an accuracy improvement during the estimation of average DE and ACLR but also permits the extraction of constant gain shaping functions that increase the overall system linearity.
    Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International; 01/2013
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    ABSTRACT: This paper details the implementation and performance of a new compact 5.8 GHz Transponder for Dedicated Short-Range Communication (DSRC). The core of the system is a low power RFIC composed of an amplifier and supeheterodyne converter, while the radiative system consists of an original low profile planar antennas operating in Left Hand Circularly Polarization (LHCP) for both Tx/Rx channel. The planar antenna technology offer the benefits of low-cost, ease of manufacture and low-profile, but it requires accurate and time-consuming tunings to reach optimal radiation and matching condition. The performance of the proposed DSRC transponder are boosted by efficient design for both Tx and Rx antennas which is based on a evolution of the original solution proposed by the authors. Measured results of a fabricated prototype show a wide and regular angular response and a net gain exceeding 15 dB in the linear range of function.
    01/2012;
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    ABSTRACT: This work reports for the first time the characterization and the bi-dimensional shaping function for a dual-band 10W ET-PA operating in concurrent mode at 870 and 1950 MHz. The characterization involved WCDMA 6.5 PAR excitation, and a detailed analysis of the signals statistic resulting from the ET mode is reported as well. The measured data reported an average DE for the concurrent modes of 49.2 %, while we observed a significant variation of the PAR, with respect to single band operation. We demonstrate that this PAR variation is due to the specific gain versus power level shape, which is established during the concurrent ET-PA operation.
    01/2012;
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    ABSTRACT: We discuss the development of a balanced GaN ET PA with optimised peak power and efficiency over 720 MHz to 960 MHz. The design was enabled by a wideband second harmonic control. The PA achieved performance delivers greater than 60% average efficiency across band at 80 W average power supporting multi-standard operation with both 2 channel WCDMA and 10 MHz LTE signals. The overall system efficiency including the ET modulator is 50% or greater with a target −50 dBc ACR across the entire bandwidth.
    Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012
  • S. Maddio, A. Cidronali, G. Manes
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    ABSTRACT: In this paper we propose a Direction of Arrival (DoA) positioning system based on a switched six-beams antenna operating in Circular Polarization at 2.45 GHz. The system is intended to operate 1D localization of generic device equipped with a common monopole antenna. The DoA estimation is possible regardless of the target antenna orientation. The system operates in circular polarization and it is designed to work without any form of calibration. We demonstrate that, in an anechoic setup, the mean errors for the DoA estimations are around 5 or 6 degrees for a wide range of target antenna orientations, while not exceed 11 degrees even in the worst case of deep fading. When operating in a complex indoor environment, the localization performance slightly degrades, but the reported experiments demonstrate that the average error is still under 10 degrees for the most common cases.
    Microwave Conference (EuMC), 2012 42nd European; 01/2012
  • S. Maddio, A. Cidronali, G. Manes
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    ABSTRACT: This paper introduces a new analytical method suitable for the design of the single-feed circular polarization (CP) microstrip patch antenna. Specifically, the proposed method imposes simultaneously the circular polarization condition as well as an arbitrary input impedance matching condition. The two conditions are enforced by an analytical method derived from an equivalent circuit model of a quasi-symmetrical patch antenna, and manipulated to control the modal detuning. This method can be used as an aid to speed up the design procedure for CP antennas even working with a numeric CAD tool. The validation of this approach is proven designing and fabricating a prototype implementing an original design, which consists of a circular disc slotted by a concentric elliptical cut with coaxial feed and operating at the center frequency of 2.45 GHz. The fabricated prototype exhibited a return loss of about 19 dB, within an impedance bandwidth of 130 MHz, a measured gain of 3.85 dB and a 0 dB axial ratio at 2.45 GHz with a corresponding modal phase difference of 87 degrees.
    IEEE Transactions on Antennas and Propagation 03/2011; · 2.33 Impact Factor
  • R. Fagotti, A. Cidronali, G. Manes
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    ABSTRACT: In this letter, we propose a novel multi-section transmission line matching technique applied to the design of a concurrent hex-band HEMT GaN power amplifier (PA). The PA has been designed for a concurrent operation at 0.9, 1.8, 2.5, 3.5, 5.2, and 5.8 GHz. Experimental results have shown minimum and maximum saturated output power levels of 33 dBm and 36.7 dBm respectively over the different frequency bands, with the power added efficiency (PAE) ranging from a minimum of 20% to a maximum of 49%. A detailed comparison between simulation and experimental results data has also been reported.
    IEEE Microwave and Wireless Components Letters 03/2011; · 1.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: form only given, as follows. Thw paper presents a 870 and 2140 MHz PA for envelope tracking (ET) operation. The design was based on a multi-section transmission line matching technique and considered the actual probability distribution function of a WCDMA signal. The prototype met similar performance to that of an amplifier based on single-band pulsed load pull, over a bandwidth of 100 MHz; reporting an average drain efficiency of 69.5% and 51.0%, and peak power levels of 54.86 and 53.96 dBm at the design frequencies.
    IEEE MTT-S International Microwave Symposium digest. IEEE MTT-S International Microwave Symposium 01/2011;
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    ABSTRACT: A new approach to the average efficiency improvement based on a combined 2-PAs architecture is presented. It uses discrete power control and dynamic supply voltage, which allows enhanced efficiency at low power level. It enables envelope tracking RF transmitter with higher average efficiency than classical approach. At 2.14 GHz CW we got an average efficiency of 42.5%, 6.1% better than the classical approach with equal peak Pout = 35 dBm. The peak increment of PAE is 13.3% at 16.4 dB of power back-off. Index Terms — envelope tracking, average efficiency, GaN PA, dynamic voltage bias control.
    01/2011;
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    ABSTRACT: In this paper we present the design of a power amplifier (PA) for envelope tracking (ET) operation based on the actual probability distribution function signal. The paper discusses the impact of envelope shaping i.e. the mapping of the drain modulated waveform to the RF output power, on system linearity and efficiency performance. The technique was applied to broadband ET PA designed around a GaAs HEMT at 940 MHz. The paper presents analytical treatment of the design technique along with characterization at device and system level. The adoption of a proper shaping function, improves ACP from -27.1dBc to -41.7dBc and increases device efficiency from 26.7% to 63.7%.
    01/2011;
  • Niccolo Giovannelli, Alessandro Cidronali, Gianfranco Manes
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    ABSTRACT: In this paper we propose a novel approach for the design of a concurrent dual-band power amplifier (PA) optimized for envelope tracking (ET) operation. The design was based around the WCDMA probability distribution function and implemented through a multi-section transmission line matching technique. This technique was applied to a concurrent 870 and 1970 MHz ET PA designed around a GaAs HEMT. The ET friendly design method has proven capable to enhance the average efficiency by a 2.2 factor over a signal bandwidth of 140MHz and 60MHz in the two carrier frequency bands respectively for the specific WCDMA signal. A detailed discussion of the design method and the validating experimental results are reported. approach based on a multi-section transmission line transformer, whose parameters are determined so that the optimum terminations at fundamentals and harmonics can be implemented. The ET optimum device loading conditions are derived from a multi-bias load pull characterization technique. The load pull data is then post processed by superimposing the probability distribution function (pdf) of the modulated signal. This pdf conscious design approach combined with the ET technique dramatically increases the PA efficiency over a wide power range, while the multi-section transformer enables the dual-band operation. The harmonically tuned dual-band matching method is described in detail in Section II, while Section III discusses the pdf conscious design approach. The design of the GaAs PA prototype for ET operation is presented in Section IV and finally the experimental results are reported in Section V.
    01/2011;
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    ABSTRACT: In this paper we present the efficiency and linearity trade-off of a dual band power amplifier (PA) for envelope tracking (ET) operation. The paper discusses the impact of envelope shaping i.e. the mapping of the drain modulated waveform to the RF output power, on system linearity and efficiency performance, for a given signal statistic. The technique was applied to a dual-band ET PA designed around a GaAs HEMT at 940 and 1940 MHz. Analytical treatment of the design technique along with characterization at device and system level are also presented in the paper.
    01/2011;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we present the design of a dual-band power amplifier (PA) for envelope tracking (ET) operation. The design was based on a multi-section transmission line matching technique and has taken into account the actual probability distribution function of the WCDMA 3GPP DL signal. The technique was applied to a concurrent 870 and 2140 MHz ET PA designed around a GaN HEMT. The ET friendly design method has proven capable to meet the performance equal to those of each single band pulsed load pull with minor loss, over a bandwidth of 100 MHz, reporting an average drain efficiency of 69.5% and 51.0%, and peak power levels of 54.86 dBm and 53.96 dBm at the design frequencies. A detailed discussion of the design method and validating experimental results data are reported.
    IEEE MTT-S International Microwave Symposium digest. IEEE MTT-S International Microwave Symposium 01/2011;
  • S. Maddio, A. Cidronali, G. Manes
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    ABSTRACT: In this paper we propose a compact positioning system based on two pattern complementary antennas printed on the same substrate. The system is capable to discriminate the azimuth component of an impinging signal working with one RSS-based technique. The unique features of the ellipse and superellipse geometry, applied to a effective design tool proposed by the authors, makes possible the design of both directive and omnidirectional radiators. The complementarity is a perfect requisite for a MUSIC-based angle of arrival detector. The antenna system is fabricated with a low-cost FR4 dielectric substrate and exhibits a matching of around -20 dB dB at center frequency of 2.47 GHz for both the antennas, within an impedance bandwidth of 100 MHz, while maintaining the compact dimension of less than 50 x 50 mm. The directional antenna shows a CP directivity of 6.0 dB and a Half Power angle of about 50°, while the omni-directional radiator shows a maximum at θo = 55°, with an Θhp of 30° . A set of localization experiments demonstrate the goodness of the proposed system, which shows a mean error of 11.94° degree.
    Wireless Technology Conference (EuWIT), 2010 European; 10/2010
  • Source
    Alessandro Cidronali, Iacopo Magrini, Gianfranco Manes
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    ABSTRACT: The contents of this chapter are mainly based on the results of the research activities performed in the context of the project TARGET­ "Top Amplifier Research Groups in a European Team" supported by the Information Society Technologies Programme of the EU under contract IST-1-507893-NOE, www.target-net.org.
    04/2010; , ISBN: 978-953-307-087-2
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    ABSTRACT: This paper focuses and provides experimental data for reconfigurable class-AB power amplifiers capable to adjust their linear power handling capability according with the application requirements. This feature is aimed at optimizing the energy requirement of the PAs. Two architectures and technologies have been considered. The first is based on SiGe HBTs with different sizes, it shows a CW PAE around 38% for the state 1 and 42% for state 2 respectively when terminated with optimum terminations. This circuit is conceived to be involved in a 1-bit step envelope tracking architecture, in which a factor two of improvement in terms of average PAE has been demonstrated. The second technique consists in controlling the output back-off of a GaN HEMT PA resulting in a significant increase of the efficiency through an, in principle, arbitrary power dynamic range. The prototype demonstrated an average PAE enhancement at 7 dB back-off of 2.1 and a maximum linear output power can be achieved up to 30 dBm, when driven by a 2.14 GHz WCDMA signal.
    RF Front-ends for Software Defined and Cognitive Radio Solutions (IMWS), 2010 IEEE International Microwave Workshop Series on; 03/2010
  • M. Mercanti, A. Cidronali, I. Magrini, G. Manes
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    ABSTRACT: This paper focuses a GaN HEMT power amplifier with 1-bit power control and provides experimental data. It relies on a new concept of power combining allowed by an adaptive gate bias control scheme. At 2.1 GHz CW the discrete power control technique enables a linear factor 3.3 efficiency enhancement at the maximum power back-off of 7 dB, while a maximum output power of 34 dBm and a peak drain efficiency of 35%.
    Radio and Wireless Symposium (RWS), 2010 IEEE; 02/2010

Publication Stats

301 Citations
34.29 Total Impact Points

Institutions

  • 1997–2013
    • University of Florence
      • Dipartimento di Ingegneria dell'Informazione
      Florens, Tuscany, Italy
    • Tohoku University
      • Department of Computer and Mathematical Sciences
      Sendai, Kagoshima-ken, Japan
  • 2009
    • Arizona State University
      Phoenix, Arizona, United States
  • 2006
    • University of Bologna
      • "Guglielmo Marconi" Department of Electrical, Electronic and Information Engineering DEI
      Bolonia, Emilia-Romagna, Italy