RF Design Engineer

Brandon Ryu (Gi-Hyon Ryu), Ph.D.

Cedar Rapids, IA 52402 949-***-**** ******.***@*****.*** GiHyon (Brandon) Ryu LinkedIn

SKILLS

· As a design engineering manager in Qorvo, Avago & now Skyworks has a full responsibility, including review of all semiconductor chips design to meet the customer specifications, assembly site build-related technical issue follow-up, internal qualification reliability issue resolving, product test items decision not to hurt production test yield, customer side qualification related technical issue follow-up and so on.

· GaAs HBT based PA design, including technology selection, power array design, bias circuit design considering driver & power stage nonlinearity, thermal coupling characteristics especially burst mode EVM, harmonic load tuning, muti-section matching with low loss & wide band simultaneously, Doherty architecture with peak & main asymmetric power dividing/combining network for optimum efficiency at backoff Pout, sensitivity analysis to generate optimum design variants.

· BAW filter design, including multiple CA combination environment, Tx-Rx leakage/isolation trade off with in-band IL, considering SMD inductor coupling with nearby components.

· RF CMOS Active-RC filter design with 60dB dynamic gain range, adoptive tunability in channel environment, automatic tuning circuit for the process variation by using TDC (Time to Digital Converter)

· mm-wave GaAs PHEMT based wideband balanced power amplifier design by using novel 3-dB coupler.

CAREER EXPERIENCE

Sr. Manager, Skyworks Solutions Inc., Cedar Rapids, IA Apr 2024 – Present

· Development of HB Tx DSM, including LTE MB/HB GaAs HBT PA, LNA, ASM with multiband BAW DPX as a MCM Team manager, targeting top tier smart phone design win.

Sr. Principal Design Engineer, OSNT Ltd., Santa Ana, CA Oct 2022 – Feb 2024

· Development of LB L-PAMiD module, including GSM & LTE PA, DPX and LNA with Antenna Switch Module as a III-V IC Design Team Lead, in charge of GSM PA design for high efficiency in multiple power modes.

Principal Design Engineer, iCana Inc., San Diego, CA June 2021 – Oct 2022

· Development of 5G sub6G small cell FEM, including PA, LNA with Antenna Switch Module as a III-V IC Design Team Lead, in charge of N77, N78, N79 PA design with Doherty architecture for high efficiency.

Principal Design Engineer, Lynnian Inc., Lake Forest, CA May 2018 – May 2021

· Development of WiFi PA for router & cell phone as a design engineer in 2.4G PA chip design, targeting Qualcomm WiFi transceiver reference board design-win. Started the sampling for Samsung Galaxy A-series model with low cost.

Design Engineering Manager, Qorvo Inc., Seoul, Korea May 2013 – Mar 2018

· Development of High Band L-PAMiD with special function of B7_B40 DLCA & B40_B41 DLCA, working as a Rx-side design leader, while Tx-side are done by Greensboro Design Center, design-win in Samsung Galaxy A-series model.

· Development of High Band L-PAMiD, which is including B7, B40 & B41 PA+ DPX with LNA, worked as a FDD side design leader, while TDD side was done by Greensboro Design Center, design-win in Samsung Galaxy S8 European model.

· Development of B30 Single Band PA + DPX module as a project team lead, design-win in Samsung Galaxy S7 North America model.

· Development of High Band MMPA module as a project team lead, first project done by Korea design center independently, targeted Samsung Galaxy Note series.

· Development of Low-Mid Band MMPA with Qualcomm ET support, as a LB main design engineer.

Principal Research Engineer, Avago (now Broadcom), Seoul, Korea Apr. 2007 – Apr. 2013

· Development of Multi-Band Multi-Mode Power Amplifier with Envelope Tracking and 2G, 3G, 4G Mode Support (Project Team Leader), which was world first ET MMPA, design-win in Samsung Galaxy Note.

· Development of Linear Quad-Band GSM/EDGE Power Amplifier as the primary supplier of Qualcomm MSM8600 series reference design (Development Team Leader)

à about 40M units shipped to RIM, HTC, Nokia, Motorola, LG, etc.

Chief Research Engineer, LG Electronics, Seoul, Korea Aug. 2000 – Mar. 2007

· Baseband Analog VGA and Filter Design for DTV terrestrial and cable multi-standard tuner by using TSMC 0.18um RF CMOS technology.

· VBIC Modeling of GaAs HBT Power Array & scalable bias circuit device using Agilent-ADS & IC-CAP

· CDMA Smart Power Amplifier Design, including optimum power array design

EDUCATION

Ph. D. (Elecrical Engineering), Seoul National University, Seoul, Korea Mar. 1995 – Aug. 2000

Dissertation : “Air-Gap Stacked Structures and Their Applications to GaAs P-HEMT MMICs”

oTable-based Large Signal Modeling of GaAs pHEMT

oDesign of Novel Air-Gap-Stacked Metal Structures

oUltra-wideband balanced amplifier using AGS 3-dB couplers.

oSmall size Ka-Band power amplifier using AGS Low impedance line.

oPhase noise reduced Ka-Band oscillator using AGS resonator.

M.S. (Electrical Engineering), Seoul National University, Seoul, Korea Mar. 1993 – Feb. 1995

Thesis : “Design and Fabrication of VCO MMIC for Mobile Communication”

PATENTS

[1] “An air-gap stacked Microstrip 3dB coupler for MMIC and fabricating method thereof”, KR1007600760000, Dec. 2002

[2] “Microstrip transmission line using air-gap stacked structure and monolithic microwave integrated circuit device having the microstrip transmission line”. KR1003756790000, Mar. 2003

[3] “Inter-Stage Matching Circuit of Multi-Stage PowerAmplifier for Mobile Communication”, KR1004807350000, Mar 2005

[4] “Smart Power Amplifier for Mobile Communication”, KR1006519750000, Nov. 2006

[5] “Automatic tuning circuit for RC filter”, KR1007600760000, Sep. 2007

PUBLICATIONS

- International Journal

[1]Gi-Hyon Ryu, Dae-Hyun Kim, Jae-Hak Lee, and Kwang-Seok Seo, "A Novel 3 dB Coupler for MMIC Using Air-Gap Stacked Microstrip Lines, ", IEEE Microwave and Guided Wave Letts.,pp. 1-3, Jan. 2000

[2] Sung-Gi Yang, Gi-Hyon Ryu and Kwang-Seok Seo, "11dB-gain and 50GHz-bandwidth coplanar distributed amplifier IC based on 0.25 non-recessed self-aligned gate GaAs P-HEMT," IEE Electron. Letts., pp. 1943-1945, Oct. 1999

[3] Yong-Joon Jeon, Hyung-Wook Kim, Hong-Teuk Kim, Gi-Hyon Ryu, Ji-Youn Choi, K. Kim, Soo-Earn Sung and Byungdu Oh, “A highly efficient CDMA power amplifier based on parallel amplification architecture,” IEEE Microwave and Wireless Components Letts.,pp. 401-403, Sep. 2004

- International Conference

[1] Gi-Hyon Ryu and Kwang-Seok Seo, "Graphical Design Method of Air-Gap Stacked Marchand Balun.", IEEE MTT-S, 2001 International Microwave Symposium.

[2] Gi-Hyon Ryu, Dae-Hyun Kim, Jae-Hak Lee and Kwang-Seok Seo, "A Novel Low Impedance Line for MMIC Using Air-Gap Stacked Structure.", IEEE MTT-S, 2000 International Microwave Symposium.

[3] YounKyu Chung, Gi-Hyon Ryu, Dae-Hyun Kim, Jae-Hak Lee, Woo-Yeon Hong, and Kwang-Seok Seo, "Characterization of source-to-drain capacitance(Cds) effect of GaAs PHEMT for microwave and millimeter-wave switch," IEEE MTT-S, 2000 International Microwave Symposium.

[4] Hong-Teuk Kim, Ki-Hong Lee, Hyung-Kyu Choi, Ji-Youn Choi, Kyung-Hak Lee, Jin-Pil Kim, Gi-Hyon Ryu, Yong-Joon Jeon, Choong-Soo Han, Keechul Kim and Kyungho Lee, "High efficiency and linear dual chain power amplifier without/with automatic bias current control for CDMA handset applications," European Microwave Conference, pp. 337-340, 2004

[5] D-H. Kim, S-G. Yang, G-H. Ryu, and K-S. Seo, "A New FET Extrinsic Parameter Extraction Method at Pinch-off Bias Utilizing Gate-Width Scaling Property," Proceedings of GaAs 98, pp. 395-400, Armsterdam, Oct. 1998.

[6] Sung-Gi Yang, Gi-Hyon Ryu, and Kwang-Seok Seo, "Fully Symmerical, Differential-Pair Type Floating Active Inductors," IEEE ISCAS-'97 pp. 93-96, 1997.

[7] J.S. Kim, C.H. Park, G.H. Ryu, K.Seo, "F-Inductor and BC-MOS Technology for Monolithic Silicon RF IC's," IEEE Radio Frequency Integrated Circuits Symposium, pp165-168, 1998

- Domestic Journal : 3 papers

[1] Gi-Hyon Ryu, Sung-Gi Yang, Kwang-Seok Seo "A coplanar wideband balanced amplifier MMIC using novel air-gap stacked 3-dB couplers," Journal of the Korean Physical Society, 2000. 12

[2] Gi-Hyon Ryu, Dae-Hyun Kim, Jae-Hak Lee, Kwang-Seok Seo, "A Novel Air-Gap Stacked Microstrip 3dB Coupler for MMIC, " Journal of Korean Institute of Electromagnetic Engineering and Science, Vol.10 (5) pp.688-693 Sep,1999.

[3] Hyun-Il Kang, Jae-Eung Oh, Gi-Hyon Ryu, Kwang-Seok Seo, " GaAs MMIC VCO/Mixer for PCS Applications," Institute of Electronics Engineers of Korea, Vol.35 (5), pp1-10, 1998

- Domestic Conference : 5 papers

[1] Dae-Hyun Kim, Sung-Gi Yang, Gi-Hyon Ryu, Kwang-Seok Seo, " A New Extrinsic Parameter Extraction Method for HEMT Utilizing Gate-width Scaling Property at Pinch-off Bias," 1998, Conference of Korean Institute of Electromagnetic Engineering and Science, pp. 111-114, 1998.

[2] Hyun-Il Kang, Gi-Hyon Ryu, Jae-Eung Oh, Kwang-Seok Seo, " GaAs MMIC VCO/Mixer for PCS Applications," Korean Conference on Semiconductors, pp. 375-376, 1998.

[3] Gi-Hyon Ryu, Kwang-Seok Seo, "Design and Characterization of VCO MMIC for Mobile Communicaion," Korean Conference on Semiconductors, pp. 107-108, 1996.

[4] Gi-Hyon Ryu, Kwang-Seok Seo, " Design and Characterization of Active Inductor MMIC for Mobile communication," Korean Conference on Semiconductors, pp.301-302, 1995.

[5] Gi-Hyon Ryu, Kwang-Seok Seo, " Design and Characterization of VCO MMIC for Mobile communication," Conference of Institute of Electronics Engineers of Korea, pp. 1014-1017, 1994.

TECHNICAL SKILLS

1.Circuit Simulator

ADS, AWR, Cadence Virtuoso, SPICE

2.EM Simulator

HFSS, ADS-FEM

3.Large Signal Device Model Extracting Tools

ADS, IC-CAP

4. Measurement Instruments

Maury Load Pull System, HP8510 Network Analyzer, HP 4142, 4145 Parameter analyzer

Spectrum analyzer, Signal source, On-wafer Probe Station, etc.

5. Computer Skill

Word Processor : MS Excel & MS-PowerPoint automation with VBA

Language : C & C++, Excel-VBA, Python, AEL, Matlab, Labview, VEE etc.

SCHOLARSHIPS and AWARDS

Academic Achievement Scholarship, Oh-woon Scholarship Foundation. (1991-1994)

Academic Achievement Scholarship, Seoul National University (1993-1996)

Educational-Industrial Complex Scholarship, Samsung Electronics Corp. (1995 – 2000)

Samsung HumanTech Student Paper Contest, Feb.2000. – Bronze Medal

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