Effect of hybrids on gain performance of dual-fed distributed amplifiers

Botterill, I.A.; Aitchison, C.S.

doi:10.1049/el:19940723

Cited by 10 publications

(10 citation statements)

References 2 publications

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“…Early investigations of the DFDA have demonstrated its gain [6] and efficiency [7], [8] advantages over the CDA. The gain of the DFDA is maximized when 180 hybrids are used [9]. For the case of an even number of field-effect transistors (FETs) and use of 180 hybrids, 180 electrical spacing between the FETs results in all FETs contributing equal output power [10] and operating into identical load trajectories [11].…”

Section: Introductionmentioning

confidence: 99%

Compact dual-fed distributed power amplifier

Eccleston

2005

IEEE Trans. Microwave Theory Techn.

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Abstract-The dual-fed distributed amplifier (DFDA) allows efficient combining of field-effect transistors (FETs) at the device level without using -way power combiners. However, the FETs must be spaced 180 , resulting in physically large circuits. In this paper, meandered artificial transmission lines (TLs) comprised of microstrip lines periodically loaded with short open-circuit stubs can be used in place of TLs to reduce the size. The approach incorporates FET input and output capacitances with the artificial TLs, thereby eliminating their detrimental effects on bandwidth and performance. Both simulation and experimental results of a class-A three-FET single-ended DFDA designed to operate at 1.8 GHz demonstrate the feasibility of this approach and the validity of the design method. The size reduction is approximately one-third compared to realization using microstrip lines only, and the maximum efficiency is greater than 35% over a bandwidth of 15%.Index Terms-Distributed amplifiers, microstrip circuits, microwave field-effect transistor (FET) amplifiers, microwave power FET amplifiers.

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Section: Introductionmentioning

confidence: 99%

Compact dual-fed distributed power amplifier

Eccleston

2005

IEEE Trans. Microwave Theory Techn.

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“…Use of 1801 hybrids results in the highest gain [9]. The FET drain voltages and currents are equal when the FETs are spaced 1801 at the centre frequency, for the case of 1801 hybrids and an even number of FETs [10].…”

Section: Introductionmentioning

confidence: 91%

“…Under the optimal operating conditions [9,10], the midpoints of the gate and drain lines of the DFDA may be earthed without disturbing FET operation at the centre frequency [11]. The resulting pair of amplifiers are called single-ended dual-fed distributed amplifiers (SE-DFDA) [12].…”

Section: Introductionmentioning

confidence: 99%

Analysis and design of class-B dual fed distributed power amplifiers

Eccleston

Kyaw

2004

IEE Proc., Microw. Antennas Propag.

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The analysis of, and derivation of design equations for, a class-B balanced single-ended dual-fed distributed amplifier is presented. This approach allows efficient combining of FET output power without multi-way power combiners, has a good port match, and is easy to design as the gate and drain transmission lines are uniform. The design method ensures that all FETs are optimally used and the efficiency is comparable to that of a conventional single-transistor class-B power amplifier using the same FET type. The design method was applied to a class-B four-FET balanced single-ended dual-fed distributed amplifier designed to operate at 1.8 GHz. Large-signal measurements revealed 8% downward shift of the centre frequency. The measured output power and drain efficiency was consistent with the simulations. The efficiency of the amplifier was comparable to a conventional single-transistor class-B power amplifier using the same type of FET.

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“…A m-derived half section is designed with m = 0.6 for best flatness across the bandwidth [13]. For the termination adjustment network, L and C are selected according to (6) and (7), where an optimum f o and Z o will be identified in the simulation analysis. For convenience, the characteristic impedance of the splitter Z o is set to 70.7 Ω, but f o has to be determined.…”

Section: Design and Simulation Analysis Of The Dual Fed Damentioning

confidence: 99%

“…The tapered drain line DA [4,5] eliminates the drain line reverse wave adopting a suitable tapering of the drain line impedance. The dual fed distributed amplifier (DFDA) topology, proposed in [6], allows efficient power combining at the load termination. Similar technique, by adding Lange couplers or Wilkinson combiners at the input and output of the DA to improve output power, gain and power-added efficiency (PAE), was demonstrated by [7,8].…”

Section: Introductionmentioning

confidence: 99%

Dual Fed Distributed Amplifier With Controlled Termination Adjustment

Kumar¹,

Limiti²,

Paoloni³

2013

PIER

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Abstract-A new circuit and technique to extend the bandwidth of the Dual Fed Distributed Amplifier (DFDA) while preserving the improvement on efficiency performance in comparison to conventional distributed amplifiers (DAs) is presented. The theoretical analysis is described in detail, and a test vehicle is realized to demonstrate the effectiveness of the proposed method. Output power of ∼ 29 dBm, gain of 10 dB, covering a bandwidth from 100 to 800 MHz, with a PAE of 20-45% is experimentally demonstrated. The results are compared with measured results of the conventional DA, demonstrating a significant improvement in bandwidth and efficiency.

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Effect of hybrids on gain performance of dual-fed distributed amplifiers

Cited by 10 publications

References 2 publications

Compact dual-fed distributed power amplifier

Compact dual-fed distributed power amplifier

Analysis and design of class-B dual fed distributed power amplifiers

Dual Fed Distributed Amplifier With Controlled Termination Adjustment

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