• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1193-1200
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• 2008

This paper describes a developed 5Watt power amplifier module fer mobile communication system using Gallium Nitride (GaN) devices. Three amplification stages such as pre-amplifier, driver amplifier, and power amplifier have been fabricated and measured separately in advance for incorporating the total power amplifier module and estimating the performances. In addition, a defected ground structure is combined with the output stage of the power amplifier module for improving harmonic rejection and adjacent channel power (ACP) characteristics. The measured performances of the GaN power amplifier module include 58dB,min of gain, 37dBm,min of output power, 50dBc,min of harmonic rejection, 35dBc,min of IMD3 for 2-tone input, and 35dBc,min of ACP at 2.1GHz frequency band.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.66-71
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• 2017

This paper describes implementation of a 165 MHz, 5 kW RF high power amplifier (HPA) for particle accelerator applications. The HPA consists of a drive amplifier for main amplifiers driving, sixteen 600 W class-AB push-pull power amplifier pallets and Wilkinson power divider/combiner using lumped LC components, which are divided/combined power amplifier pallet outputs. To detected the amplifier circuit of normal and reflected output power conditions, we used a bidirectional coupler. To radiate heat of main power amplifier, we were used an water-cooled copper plates to go through a water for radiation of heat. The HPA of center frequency 165 MHz has archived an efficiency of 62.5 % at 5 kW of power level experimentally.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.88-93
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• 2006

In this paper, smaller load has been used compared with the conventional Doherty amplifier and PBG structure have been employed to suppress IMD (Inter-modulation Distortion) and improve PAE (Power Added Efficiency). And The PBG structure has been employed on the output macthing network of Doherty amplifier. The proposed power amplifier has been improved more the IMD3 by 5.5 dBc, and the average PAE by $5\%,$ at peak output power, $18\%$ at 8dB back-off point respectively than the conventional Doherty power amplifier.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.1
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• pp.63-69
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• 2010

In this paper, a new design method of asymmetrical configuration of main amplifier and peaking amplifier using changed bias point is proposed for excellent linearity, instead of the conventional Doherty structure. We have utilized the uneven wilkinson power divider for the unequal power drive at the input network of amplifiers. And we proposed a compensating method of the decreasing efficiency due to improving linearity using 3-stage Doherty structures. From the simulation results of asymmetrical Dohertry power amplifier and asymmetrical 3-stage Doherty power amplifier with uneven power drive are implemented. From the implementation and measurement results of the each amplifier, IMD characteristics have -55 dBc as the good efficiency of 13% compensates the decreased entire efficiency due to the improving linearity characteristics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.65-68
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• 2004

The performances of millimeter wave Power amplifier have been improved by using PBG (photonic bandgap structure) in this paper. The PBG structure has been optimized to obtain the lowpass characteristics in Ka band and employed at output port of Ka band power amplifier. The harmonics of the power amplifier have been suppressed by the PBG of output port and the proposed PBG has suppressed the second harmonic to 40dBc around 50 GHz. The improvements of IMD and PAE of the amplifier employing the PBG structure are obtained $15\%$ and $25\%$, compared with those of the conventional Ka band power amplifier, respectively.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.3
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• pp.188-196
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• 2004

Amplifier linearity plays a major role in the quality of mordern communication systems. The Power amplifier should be operated near saturation region to achieve high efficiency But at this region amplitude and phase distortions of the amplifier remarkably increase with the input power increase and cause a significant adjacent channel interference. In this paper, an independently controllable AM/AM and AM/PM predistortion linearizers consisted of two bias feed resistance linearizers is proposed. This linearizer allows independent adjustment of the AM/AM and AM/PM curves by using two adjustable voltages to compensate tile power amplifier non-linearities. The predistortion linearizer can improve the ACPR by 5.3dB with cdma2000 multi carrier signals. And by applying this linearizer to two-tone(880MHz) power amplifier, third order IMD products are improved up to 8(dB).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.14-17
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• 2008

This paper describes the simulation of a phase splitter for the design of Chireix Outphasing power amplifier. Phase splitter separate the input signal with $0[^{\circ}]$ into the signal with $+90[^{\circ}]$ and $-90[^{\circ}]$ Chireix Outphasing power amplifier get a linearized output from the signal amplifying and combining the separated signal with the phase of $+90[^{\circ}]$ and $-90[^{\circ}]$ of the phase splitter. phase splitter is the core device when designing Chireix Outphasing power amplifier. It is very difficult to design phase splitter with the difference of $90[^{\circ}]$. This phase splitter is used to design the difference of $180[^{\circ}]((90[^{\circ}]+{\alpha}),\;-(90[^{\circ}])+{\alpha}))$ using simulation tool and a differential amplifier.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.317-320
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• 2000

In this paper, a 0.5W, 2GHz high-efficiency class A power amplifier using the dynamic bias control is proposed. First of all, the drain bias control amplifier is analyzed theoretically and designed with commercial devices. Simulation results show that the proposed amplifier has a significant improved efficiency, compared to fixed bias power amplifier.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.941-944
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• 2000

This paper proposes, for the first time, the design of class I pull-push power amplifier. With the new design, the output power is increased by four times when compared to conventional single-end class I connection amplifier with the same supply voltage. The performance of the proposed amplifier is verified by with a 100-kHz power amplifier constructed using general-purpose NPN transistors.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.89-94
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• 2007

For successful implementation of multi-standard transmitter, reconfigurable architecture and component design are essential. This paper presents a reconfigurable CMOS power amplifier designed CMOS 0.25 um process. Designed power amplifier can be operated at 0.9, 1.2, 1.75, and 1.85 GHz. Also, it can be used at 2.4 GHz by using bonding wire inductor. The interstage matching network is composed of two inductors and four switches, and operation frequency can be varied by controlling switches. Proposed power amplifier can be used as a power amplifier in low power applications such as ZigBee or Bluetooth application and used as a driver amplifier in high power application such as CDMA application. Designed power amplifier has 18.2 dB gain and 10.3 dBm output power at 0.9 GHz. Also, it represented 10.3 (18.1) dB gain and 5.2 (10) dBm output power at 1.75 (2.4) GHz.