A. Al Tanany

Technische Universität Berlin, Berlín, Berlin, Germany

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Publications (15)2.23 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: This paper presents the experimental analysis of the injection of harmonic signals at the gate of a RF power transistor. The harmonic injection leads to an optimized shape of the waveforms at the inner transistor resulting in an improvement of the efficiency performance. A triplexer, allowing injecting the second as well as the third harmonic into the transistor is designed for these experiments, although in the present work only the second harmonic is used. At 2.6 GHz, the experimental results show that for a 25 W GaN HEMT RF power device, the drain efficiency can be improved by up to 6%.
    01/2011;
  • Ahmed Al Tanany, Daniel Gruner, Georg Boeck
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    ABSTRACT: This paper presents a GaN HEMT based harmonically tuned broadband power amplifier. The amplifier uses the CGH40120F GaN device from Cree Inc. and delivers 100 W output power across the bandwidth 1.55–2.25 GHz. The minimum power added efficiency (PAE) over the bandwidth is higher than 60 % with maximum values up to 70 %, respectively. Measurements using digital modulated signals were performed, too. At 38.5 dBm average output power more than 40 dBc ACLR has been achieved for an UMTS signal applying memory DPD. The PA covers the frequency range of modern wireless standards like DCS1800/LTE, PCS1900/LTE and WCDMA/LTE and is well suited for multi-band, mult-standard applications.
    01/2011;
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    ABSTRACT: The analysis, design, and evaluation of medium-voltage laterally diffused metal oxide semiconductor (LDMOS) transistors for wireless applications up to 6 GHz is presented. Using an optimized N-LDMOS transistor, power devices of different transistor geometries were fabricated in a standard 0.25-μm bipolar complementary metal oxide semiconductor (BiCMOS) technology with and without on-chip stabilization networks. The influences of the finger geometry and the stabilization networks on the RF performance were studied based on small-signal and large-signal on-wafer measurements. It was analytically shown and experimentally verified that transistor geometries with reduced gate width per finger but higher number of fingers are advantageous regarding the maximum oscillation frequency. From the source/load-pull characterization of a 1.8-mm total gate-width device, state-of-the-art, large-signal performance with a maximum output power of 29.7 dBm and a peak drain efficiency of 44% were obtained at 5.8 GHz. Power evaluation of the LDMOS transistors was also carried out in designed hybrid power amplifier modules targeted for vehicular wireless LAN applications. In the 5.8-5.9 GHz band, an output power of 1 W at 1-dB power compression, an adjacent channel power ratio of -38 dBc and an error vector magnitude of 3% at 1 dB peak power compression are reported.
    IEEE Transactions on Microwave Theory and Techniques 01/2011; · 2.23 Impact Factor
  • D. Gruner, K. Bathich, A. Al Tanany, G. Boeck
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    ABSTRACT: In this paper a GaN-HEMT Doherty amplifier targeted for vehicular applications at 6 GHz is presented. The harmonic tuning of the selected bare-die transistors was investigated and implemented in order to improve the overall large-signal performance. The Doherty amplifier was studied and optimized on device reference plane level using two equally sized 8-Watt GaN devices for the main class-AB and the peaking class-C amplifiers. The measured maximum output power was 41.5 dBm with 63 % peak drain efficiency (50 % power added efficiency). At 6 dB output power back-off a drain efficiency of 49 % (42 % power added efficiency) was obtained. The linearity of the amplifier was tested by applying modulated signals according to the IEEE 802.11p standard. At 34 dBm average output power a drain efficiency of 43 % was achieved for this high dynamic range OFDM signal. After digital pre-distortion, the related adjacent channel power ratio could be reduced from −31 dBc to values below −43 dBc without significant impact on the efficiency performance.
    01/2011;
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    ABSTRACT: In this paper the design of a high power balanced Doherty power amplifier (PAs) will be reported. The Doherty PA was designed to achieve high average efficiency for digitally modulated signals with high peak to average power ratio (PAR) used in third (3G) and fourth (4G) generation systems. To achieve high efficiency up to 6 dB output power back-off (OPBO), a combined design technique of uneven power divider and use of unsymmetrical devices has been considered. At same time in order to improve its linearity and higher power capability a balanced structure, which combines two identical Doherty amplifiers has been proposed. For demonstration, a 120 W Doherty PA has been implemented to operate at 2.5 GHz. A drain efficiency of 57% (48% power added efficiency (PAE)) has been measured at its maximum output power of 50.8 dBm. Efficiency of more than 40% at the 6 dB output power back-off has been also measured. Moreover, the Doherty PA has been characterized using two-tone signal of 10 MHz spacing which resulted in a third order inter modulation ratio of -35 dBc at the 8.5 dB output power back-off level.
    01/2011;
  • A. Al Tanany, D. Gruner, A. Sayed, G. Boeck
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    ABSTRACT: The influence of the harmonic impedances on the power amplifier performance is presented across a wide bandwidth. Based on this method, a set of impedances for the first, second and third harmonics across the band was found which do not affect output power (P<sub>Out</sub>) and power added efficiency (PAE). At the 3 dB compression point, the measured P<sub>out</sub> is 40 dBm ± 1.5 dB, and the PAE is between 58.7 %-78.0 % across a bandwidth of 1.5 GHz-2.75 GHz (60 % bandwidth). A linearity measurement was done by sweeping the drain supply voltage, gate bias voltage and injecting a WCDMA drive signal to find the best linearity without affecting the performance. A linearity of -36 dBc at 8.5 dB back-off power from the 3 dB compression point of P<sub>out</sub> was found at 2.15 GHz.
    Microwave Integrated Circuits Conference (EuMIC), 2010 European; 10/2010
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    ABSTRACT: In this paper, we report the benefits of wide bandgap technology in UMTS applications. For this purpose, three, 10 W, 2.14 GHz class AB power amplifiers based on SiC MESFET and GaN HEMTs have been designed. A model based design procedure with simulated load pull characterization was used and the achieved results of the implemented amplifiers show an excellent performance from the efficiency/ linearity point of view. A small signal gain of 9, 13 and 15 dB for PA1 (SiC MESFET, Cree), PA2 (GaN HEMT, Eudyna) and PA3 (GaN HEMT, Cree), respectively have been obtained. An output power of (40 - 41.5 dBm) and Max. PAE of (43 - 56%) have been achieved, too. Linearity performance based on gain compression, phase distortion, two-tone intercept points and finally ACLR characterization has been done. The results are compared and discussed in detail. It is found that, among state-of-the-art WBG transistor technologies, WBG offers the optimum solution for highly linear, high efficient power amplifiers in wireless communications to date.
    01/2010;
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    ABSTRACT: Switch mode power amplifiers offer high efficiency approaching 100% for an ideal case. This paper discusses the operation mode of broadband switch mode class-E power amplifier designed previously by the authors for UHF applications (600 - 1000 MHz). A method to extract the waveforms at the die reference plane from the time domain analysis using 50 Ω environment system is discussed. It has been observed that the designed class-E power amplifier operation was not maintained ideally over the entire band, however, it was operating close to the class-E operation.
    01/2010;
  • A. Sayed, A. Al Tanany, G. Boeck
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    ABSTRACT: In this paper, a 0.35-8 GHz, 5 W, linear power amplifier based on GaN HEMT die is reported. Load pull characterization was used to optimize the power performance in the operating bandwidth. 3D-EM simulations were also performed to model the coaxial 50 Ohm connections, bond wires and matching networks resulting in an excellent agreement between simulations and measurements. Regarding the performance, the designed single stage PA has exhibited 9 ± 1 dB gain, an output power (Pout) of greater than 37 dBm (5 W), worst power added efficiency (PAE) of 20% over a multi-octave (0.35-8 GHz) bandwidth. The PA has been also fully characterized from the linearity point of view based on single-tone (AM/AM, AM/PM) and two-tone techniques (with 100 kHz frequency spacing). An AM/AM and AM/PM distortions of only ± 0.5 [dB/dB] and ± 2 [dB/deg] at 8 GHz have been observed. As a measure of linearity in two-tone performance an output third-and second- order intercept points (OIP3, OIP2) have been extracted over the whole bandwidth. An OIP3 of ≥ 49 dBm and OIP2 of ≥ 67 dBm can be achieved.
    Microwave Conference, 2009. EuMC 2009. European; 11/2009
  • A. Al Tanany, A. Sayed, G. Boeck
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    ABSTRACT: In this work a broad-band class E power amplifier (PA) is designed, manufactured and measured. 400 MHz bandwidth with a center frequency of 800 MHz was realized using a GaN HEMT device. A novel and easy circuit topology is proposed for broad-band bandpass filter with integrated output matching network. Different filter types are discussed, suitable topology is chosen and design equations are shown. A maximum drain efficiency of 87.8 % (PAE = 80.6 %) is observed. Maximum output power of 49 W is measured with 16.3 dB power gain at the 1 dB compression point.
    Microwave Symposium Digest, 2009. MTT '09. IEEE MTT-S International; 07/2009
  • A. Al Tanany, A. Sayed, G. Boeck
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    ABSTRACT: This work presents a Class F<sup>-1</sup> power amplifier (PA) operating at 2.35 GHz. An output power of 40 W (46 dBm) was achieved with 10 dB gain. The maximum drain efficiency was measured to be 60.8% (PAE = 55.7 %). The power amplifier was implemented using GaN pHEMT. The realization of the optimum load resonator was designed by a microstrip resonator, for the first four harmonics. The resonator achieves an optimum load for the transistor at the fundamental frequency.
    German Microwave Conference, 2009; 04/2009
  • A. Sajjad, A. Sayed, A. Al Tanany, G. Boeck
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    ABSTRACT: This paper exhibits a 10 W class AB highly linear power amplifier (PA) for a frequency of 2.14 GHz using GaN HEMT. Power and linearity measurements and simulations illustrate stupendous correspondence. An output power of 11 W (41 dBm) with maximum drain efficiency (eta) of 72 % (PAE 56 %) is achieved. Linearity measurements were made with a frequency spacing of 100 KHz and output third-order and second-order intercept points (OIP3 and OIP2) were observed to be 48 dBm and 80 dBm respectively.
    01/2009;
  • A. Al Tanany, A. Sayed, G. Boeck
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    ABSTRACT: This paper presents a 50 W current mode class D (CMCD) power amplifier (PA) operating at 2.14 GHz. The PA is implemented using GaN pHEMT. The peak drain efficiency (iquest) is 62.7% and power added efficiency (PAE) is 60.3%. A resonator without an inductor was implemented to eliminate any loss that results from the low quality factors. The resonator uses narrow microstrip DC-feed lines located close to the drain leads which is used as resonator inductance. A model of the output capacitance (i.e.; C<sub>ds</sub>) was extracted from the die model and is used as a part of the resonator. Finally, a comparison between an ideal parallel LC with the proposed resonator was simulated to achieve the required impedance termination.
    Microwave Conference, 2008. EuMC 2008. 38th European; 12/2008
  • Ahmed Sayed, Ahmed Al Tanany, Georg Boeck
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    ABSTRACT: We present in this paper a linear 20 W broadband power stage based on GaN HEMT. An efficient procedure has been used to optimize the broadband performance. Source/Loadpull technique has been applied to extract the optimum source and load impedances for maximum output power. Power losses due to both matching and biasing networks have been minimized as well. At VDS = 50 V and IDS = 850 mA, the design provides a frequency range from 200 MHz to 3 GHz with a gain of 11±1.5 dB and P1dB output power and PAE greater than 20 W and 25 %, respectively. Linearity performance based on two-tone technique has been analyzed resulting in an output IP3 of = 50 dBm over the full bandwidth at a frequency spacing of 100 kHz. Design procedure, simulation and first measured results are presented in this paper.
    Microwave Conference (GeMIC), 2008 German; 04/2008
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    ABSTRACT: Class E power amplifiers (PA) offer high efficiency. However, with broadband class E load network, the harmonic performance degrades. In this work, this disadvantage has been overcome by implementing a new type of load circuitry. The whole PA chain consists of three stages to provide high gain and output power at the same time as required for two-way radio applications. The final PA stage uses a broadband class E load network. A novel idea of series LxCx with high Q roll-off harmonic filter (elliptical type) was used for this implementation. On measurement level, efficiency of 70 % and second harmonic suppression of 73 dBc across a wide bandwidth (135 to 175 MHz) is demonstrated at an output power of 6.5 W. The supply voltage was 7.2 V. According to the authors¿ best knowledge, the efficiency and harmonic results are the highest reported so far in the VHF frequency range with 40 MHz bandwidth.
    Microwave Conference (GeMIC), 2008 German; 01/2008