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A high-power solid-state RF source driven by a doubly-differential signal
Jeon, Sanggeun,Rutledge, David B. Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.7
<P>This letter presents a new solid-state RF source generating kW-level output power at HF band.Four power transistors are driven in a doubly-differential way, operated in a switching mode, and combined together to produce high output power. A multilayered input feed network is carefully designed, such that an accurate doubly-differential signal is provided to the transistors. The output matching and combining circuitry is optimized toward a high efficiency. The implemented RF source produces a CW signal of 1.5 kW at 29 MHz with a drain efficiency of 85%. The measured high efficiency is attributed to the well-balanced and symmetric switching-mode operation of each transistor, which is verified experimentally by a thermal image. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1489–1492, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25230</P>
Seungwon Park,Sanggeun Jeon IET 2015 Electronics letters Vol.51 No.9
<P>A wideband power amplifier (PA) with high output power and efficiency over the entire X-band is implemented in a 0.11 μm CMOS technology. To achieve high efficiency in the wideband, a new harmonic-tuned technique is proposed for the output matching network of the PA, while no radio frequency (RF) choke is used for DC bias. Measurement results show that the output power and power-added efficiency (PAE) are no less than 19.5 dBm and 22.6%, respectively, over the entire X-band. The peak PAE is 28.9% with an output power of 20.3 dBm at 9 GHz.</P>
A Transformer-Matched Millimeter-Wave CMOS Power Amplifier
Seungwon Park,Sanggeun Jeon 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.5
A differential power amplifier operating at millimeter-wave frequencies is demonstrated using a 65-nm CMOS technology. All of the input, output, and inter-stage network are implemented by transformers only, enabling impedance matching with low loss and a wide bandwidth. The millimeter-wave power amplifier exhibits measured small-signal gain exceeding 12.6 dB over a 3-dB bandwidth from 45 to 56 GHz. The output power and PAE are 13 dBm and 11.7%, respectively at 50 GHz.
Harmonic-Tuned High Efficiency RF Oscillator Using GaN HEMTs
Seunghyun Lee,Sanggeun Jeon,Jinho Jeong IEEE 2012 IEEE microwave and wireless components letters Vol.22 No.6
<P>A harmonic-tuned high efficiency oscillator is designed using gallium nitride (GaN) high electron mobility transistors (HEMTs). The harmonic load-pull simulation is performed to find the voltage and current waveforms and to locate the optimum load impedance for high efficiency operation of the transistor. Then, the feedback network for the oscillation is synthesized based on the load-pull data. The series resonant circuit is employed in the feedback network to provide open circuit to the load network at harmonic frequencies. Therefore, the load network can be designed separately from the feedback network to present the optimum harmonic load impedances. In this way, the transistor in the oscillator can achieve the optimum voltage and current waveforms determined by the harmonic load-pull simulation. The fabricated GaN oscillator using the proposed design approach shows the maximum efficiency of 80.2% and output power of 35.1 dBm at 2.42 GHz under drain bias voltage of 22 V.</P>
H-Band Power Amplifier Integrated Circuits Using 250-nm InP HBT Technology
Jungsik Kim,Sanggeun Jeon,Moonil Kim,Urteaga, Miguel,Jinho Jeong IEEE 2015 IEEE transactions on terahertz science and technol Vol.5 No.2
<P>In this paper, H-band (220-325 GHz) power amplifier (PA) integrated circuits (ICs) are presented using 250-nm InP HBT technology, where a cascode topology was adopted to achieve high gain and high output power. Three PAs were designed: PA1 was implemented with two-stage cascode HBTs, PA2 combined two PA1s, and PA3 combined four PA1s, by using Wilkinson couplers without isolation resistors. Electromagnetic simulations were carried out for the accurate design of passive circuits such as a microstrip line, a capacitor, and RF pads. The measured insertion loss of the RF pad and Wilkinson coupler was as low as 0.24 dB and 0.70 dB, respectively, at 300 GHz. The three PAs exhibited a measured gain higher than 15 dB with good return losses at 300 GHz. The output powers scaled well with total emitter area of the PAs. PA3 exhibited a maximum output power of 13.5 dBm at 301 GHz. To the best of the authors' knowledge, this corresponds to the highest output power among the previously reported solid-state PAs in this frequency range.</P>
A Transformer-Matched Millimeter-Wave CMOS Power Amplifier
Park, Seungwon,Jeon, Sanggeun The Institute of Electronics and Information Engin 2016 Journal of semiconductor technology and science Vol.16 No.5
A differential power amplifier operating at millimeter-wave frequencies is demonstrated using a 65-nm CMOS technology. All of the input, output, and inter-stage network are implemented by transformers only, enabling impedance matching with low loss and a wide bandwidth. The millimeter-wave power amplifier exhibits measured small-signal gain exceeding 12.6 dB over a 3-dB bandwidth from 45 to 56 GHz. The output power and PAE are 13 dBm and 11.7%, respectively at 50 GHz.
Variation in RF Performance of MOSFETs Due to Substrate Digital Noise Coupling
Yongho Oh,Sanggeun Jeon,Jae-Sung Rieh IEEE 2010 IEEE microwave and wireless components letters Vol.20 No.7
<P>In this letter, the variation in the key RF performance parameters of MOSFETs in the presence of the substrate digital noise coupling is investigated. The parameters, including f<SUB>T</SUB> and f<SUB>max</SUB>, showed substantial change up to ~20% with realistic level of noise injection. It is shown that such change in the RF performance with the noise injection is due to the threshold voltage ( V<SUB>T</SUB>) variation. The observed V<SUB>T</SUB> variation is attributed to the virtual body effect due to the substrate potential fluctuation by the coupled substrate digital noise.</P>
A 15–40 GHz CMOS True-Time Delay Circuit for UWB Multi-Antenna Systems
Sanggu Park,Sanggeun Jeon IEEE 2013 IEEE microwave and wireless components letters Vol.23 No.3
<P>A CMOS true-time delay (TTD) circuit operating from 15 to 40 GHz is presented for integrated UWB multi-antenna systems. The TTD circuit employs a distributed active switching structure in which eight cascode switches are distributed along transmission lines, leading to 3-bit variations of the group delay. The size of the switches and the characteristic impedance of the transmission lines are carefully scaled so as to minimize loss variation among the different delay states, while maintaining flat delay performance over a wide bandwidth. The circuit is implemented in a bulk 0.13-μm CMOS technology and exhibits a total variable group delay of 40 ps with an average resolution of 5 ps from 15 to 40 GHz. The insertion loss was 14 dB with a maximum RMS variation of 1.6 dB, while the input and output return loss was better than 10 dB over the operating bandwidth.</P>
Compact Two-Way and Four-Way Power Dividers Using Multi-Conductor Coupled Lines
Seunghoon Kim,Sanggeun Jeon,Jinho Jeong IEEE 2011 IEEE microwave and wireless components letters Vol.21 No.3
<P>In this letter, new two-way and four-way power dividers are proposed using quarter-wave long multi-conductor coupled lines. The design equations for a two-way power divider are derived by analyzing a three-conductor coupled line. Then, the structure is extended to propose a planar four-way power divider with compact size. The fabricated two-way and four-way power dividers at 2.0 GHz show an excellent performance in the insertion loss, impedance matching at all ports and isolation between output ports.</P>
A G-Band Frequency Doubler Using a Commercial 150 nm GaAs pHEMT Technology
Iljin Lee,Junghyun Kim,Sanggeun Jeon 한국전자파학회JEES 2017 Journal of Electromagnetic Engineering and Science Vol.17 No.3
This paper presents a frequency doubler operating at G-band that exceeds the maximum oscillation frequency (fmax) of the given transistor technology. A common-source transistor is biased on class-B to obtain sufficient output power at the second harmonic frequency. The input and output impedances are matched to achieve high output power and high return loss. The frequency doubler is fabricated in a commercial 150-nm GaAs pHEMT process and obtains a measured conversion gain of −5.5 dB and a saturated output power of −7.5 dBm at 184 GHz.