Vectorially Combined Distributed Power Amplifiers for Software-Defined Radio Applications

Kumar, Nagendra; Limiti, Ernesto; Paoloni, Claudio; Collantes, J.M.; Jansen, R.H.; Yarman, Sıddık B.

doi:10.1109/tmtt.2012.2207914

Cited by 19 publications

(27 citation statements)

References 22 publications

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“…Therefore, the phase synchronization between gate and drain is difficult to achieve over the wide frequency range. 7 Real-frequency techniques (RFT) have been incorporated at input of gate line to offer wideband matching solution. 8 The approach has been validated in experimental level with GaN HEMT device, good results are achieved over the entire bandwidth for the need of public safety radio requirements, particularly from 80 to 2100 MHz.…”

Section: Introductionmentioning

confidence: 99%

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Broadband GaN HEMT distributed power amplifier design with phase adjustment

Yan

Kumar

Latef

et al. 2017

Micro & Optical Tech Letters

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This letters presents a new wideband power amplifier approach to achieve high performance of wideband frequency operation from low frequency such as 80-2100 MHz for two-way radio applications. The approach is referring to distributed power amplifier with phase adjustment of the gate line network to balance with drain line network (specifically with drain line tapering). Experimental of the prototype level with gallium nitride highelectron-mobility-transistor demonstrated output power of 41 dBm, flat gain at 12 dB, and bandwidth covering 80 MHz to 2.1 GHz with power added efficiency of 45% under 28 V drain bias. According to the author's knowledge, this work has illustrated a significant enhancement in efficiency over the conventional topology, low cost implementation, and offers wideband operation for public safety applications.distributed power amplifier, GaN HEMT, phase adjustment 1 | I NT RODU CTI ON ADIO frequency (RF) and microwave communication technology has an endless demand on wide band frequency operation and power amplifier (PA) design has grown in research area. However, for multiband operation within ultra-highfrequency (UHF) bands (up to 3 GHz), the conventional PAs are bigger in size, costly, and has limitation on efficiency. 1 Moreover, PA is crucial in wireless transmitters where designing flat gain PAs in broadband comes into prominence. 2 There are several research design distributed power amplifier (DPA) with hybrid and monolithic microwave integrated circuit (MMIC) technology. The hybrid DPA in Refs.[3,4] using gallium nitride high-electron-mobility-transistor (GaN HEMT) have demonstrated high output power levels of 12 and 20 W respectively, with good efficiency of 45% and 64%. The power efficiency was optimized with the nonuniform drain and gate line geometry. 3 On the other hand, the MMIC amplifiers has been presented in the literature, 5,6 with superior wide range performance up to 8 GHz and less parasitic to deal with. However, with the low-cost solution, hybrid amplifiers will be more suitable.In this letter, we introduced an approach to optimize the power performance of DPA especially at higher end frequency without trade-off the low frequency with phase adjustment controlled at gate line. Due to the fact when pushing all the current to the single load termination, each device at drain side seeing different impedance . Therefore, the phase synchronization between gate and drain is difficult to achieve over the wide frequency range. 7 Real-frequency techniques (RFT) have been incorporated at input of gate line to offer wideband matching solution. 8 The approach has been validated in experimental level with GaN HEMT device, good results are achieved over the entire bandwidth for the need of public safety radio requirements, particularly from 80 to 2100 MHz. Certainly this could be an interesting approach for industrial needs for low cost and small area implementations. | D ES I GN M ETHO DOL OGYA new broadband DPA architecture is proposed as depicted in Figure 1. The need to impr...

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Section: Introductionmentioning

confidence: 99%

“…Only a few attempts have contributed to both harmonic suppression and unequal power division. 7,8 However, the maximum power division ratio (PDR) of the coupler proposed in Ref. [7], is around 3 dB, since higher PDR leads to lower coupled line impedance, which is hard to be implemented.…”

Section: Introductionmentioning

confidence: 99%

Broadband GaN HEMT distributed power amplifier design with phase adjustment

Yan

Kumar

Latef

et al. 2017

Micro & Optical Tech Letters

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“…Power amplifier (PA) designs, which are stable under ideal 50  terminations, may become unstable [1][2][3][4][5] under antenna mismatch conditions in realistic wireless environments, such as where the antenna input impedance is affected by objects in its vicinity [1][2][3][4][5][6][7][8]. Therefore, evaluation of the stability robustness against load mismatches is essential for reliable operation.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, evaluation of the stability robustness against load mismatches is essential for reliable operation. The works [1][2][3], based on pole-zero identification, require a systematic test of impedances on the Smith chart and involve a high computational cost. In [9] a new methodology was presented for an efficient calculation of the stability boundaries using concepts from bifurcation theory [10].…”

Section: Introductionmentioning

confidence: 99%

“…The analysis in [9] takes into account that the output load will have certain frequency dependence, neglected in previous works [1][2][3], and therefore, it will exhibit different values at the various frequencies k f in and kf in + f, where k is an integer [9]. However, as will be rigorously verified in this paper, if the output circuit exhibits a filtering behavior, not all the frequencies kf in and kf in + f will have an impact on the circuit stability.…”

Section: Introductionmentioning

confidence: 99%

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Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Suárez

Ramírez

Sancho

2014

IEEE Trans. Microwave Theory Techn.

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1 Abstract -Novel criteria are presented for small-and large-signal stability analysis of microwave circuits under output mismatch effects. They are based on concepts from bifurcation theory, which enable the derivation of general equations for the stability boundaries that depend on the termination load. The boundary calculation does not require any optimization of the circuit parameters. Instead, it is based on the direct calculation of an admittance function obtained through circuit linearization about either the dc solution, in the small-signal stability analysis, or the periodic solution, in the large-signal one, with low computational cost. As will be demonstrated both with homotopy and bifurcation concepts, the Hopf locus obtained in this way delimits a stable region and a potentially unstable one. In a large-signal stability analysis, the sidebands that influence the stability properties are identified, which depend on the particular amplifier topology and its filtering effects. The stability boundaries are then calculated with the conversion matrix approach for all load impedance values at the relevant harmonic and sideband frequencies. For the derivation of absolute stability conditions, a new scattering type matrix is proposed describing the circuit response from the output reference plane with respect to the two sidebands about the input carrier. The new methodologies and formulations have been validated by independent simulations using pole-zero identification, and by measurements.

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2-6 GHz GaN distributed power amplifier MMIC with tapered gate-series/drain-shunt capacitors

Bae

Kim

2016

Int J RF and Microwave Comp Aid Eng

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In this article, using a 0.25 lm GaN HEMT process, we present a 2-6 GHz GaN two-stage distributed power amplifier MMIC that utilizes tapered gate series capacitors and nonuniform drain transmission lines with tapered shunt capacitors to simultaneously obtain a linear gain enhancement and optimum load line for each transistor. By using well-derived equations to provide each transistor with the optimum load impedance and to tune the phase delay between the input and output transmission lines, the nonuniform distributed power amplifier is designed for second-stage amplification, and satisfactory performance is demonstrated. The phase balance and tapering of the gate series capacitors have a role in improving the linear gain of the two-stage amplifier. The measured data show a linear gain of 22 6 1 dB, an input/output return loss of more than 15 dB, saturated output power of 41.2-43.1 dBm under a continuous-wave mode, and a power-added efficiency of 18-22% from 2 to 6 GHz which are very competitive values compared with previous works. V C 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:456-465, 2016.

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Vectorially Combined Distributed Power Amplifiers for Software-Defined Radio Applications

Cited by 19 publications

References 22 publications

Broadband GaN HEMT distributed power amplifier design with phase adjustment

Broadband GaN HEMT distributed power amplifier design with phase adjustment

Stability Analysis of Power Amplifiers Under Output Mismatch Effects

2-6 GHz GaN distributed power amplifier MMIC with tapered gate-series/drain-shunt capacitors

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