Research

Research Highlights

Undergraduate Student Seungjun Lee Awarded the 2023 IEEE MTT-S Undergraduate Scholarship

: Only up to 12 undergraduate scholarships are awarded worldwide each year

: He will be honored by IEEE MTT-S in June 2024 in Washington DC.

: Research Topic - Generalized similarity transformations for coupling matrices of arbitrary topologies



Graduate Student Jongheun Lee Won First Place in Student Design Competition 

: 2023 IEEE MTT-S Int. Microwave Symposium, San Diego, CA

: Reflectionless Highpass Filter Design For Load-Pull Measurement Setups

: Low loss and Wide Upper Passband

: Reflectionless Response Over Wide Frequency Range 



Undergraduate Student (Junior) 

Seungjun Lee's Paper Published in IEEE Transactions on Microwave Theory and Techniques

: Synthesis of N-Foster-Section Filter With Maximum 2N Prescribed Transmission Zeros by Heuristic-Aided Graph Search



Reflectionless Dual-Passband Waveguide Filter

: Accurate Synthesis (Zero Reflection At All 

   Frequencies)

: Arbitrary Cutoff Frequencies

: Two Passbands

: Measured Reflectionsless Response Over 

  Entire WR-42 Band ( 18-26.5 GHz)

Electroformed Seamless Waveguide Filter

: PIM (Passive Intermodulation)-Free 

: No Tuning Screws

: Corrugated LPF + Dual-Mode BPF

: No Rounded Corners in Resonators

: X-Band Satellite Communications

: Dual-Mode Technique

: Transmission Zeros

Graduate Student Jongheun Lee Won First Place in Student and Young Engineer Design Competition

: APMC 2022, Yokohama, Japan

: Passive Track

: 22 Participants

: Small-size low-loss high-rejection BPF design

US Patent

: Reflectionless Filter 

: Universal Topology

: Single Layer

: Arbitrary Transmission Response

: No Reflection From DC to Infinity

Ultra-Narrowband Cavity Filter

: 0.17 % Bandwidth 

: S-band

: Dual-Mode Technique

Terahertz Reflectionless Filter

: f0 ~ 275 GHz

: S11<-10 dB over 220 - 330 GHz (WR-3.4)

: Fabrication by Milling

Millimeter-Wave SIW Filter

: f0 ~ 38.8 GHz

: Single Substrate 

: Surface Mountable

: Transmission Zeros

Tunable LTCC Filter

: Bandstop Response

: Attenuation > 60 dB at f0 

: No Reflection in Stopband

: Frequency Tuning (1.6 : 1)

: Resonator Q ~ 2


Current Research Areas

 

Multi-Function Microwave Circuits

Reconfigurable and Miniaturized Microwave Filters

High-Dielectric Ceramic Waveguide Filters 

K-Band Cavity Filters for Satellite Applications

Wireless Power Transfer Systems

Microwave Circuits for Next-Generation Radar Systems

 

 

Past Research Areas and Research Interests

 

Microwave Equipment for Satellite Applications

    Dual-Mode Waveguide Filters

    Group-Delay Equalizers

    Self-Equalizer Filters

    Input Demultiplexer (Circulator Chain Structure)

    Output Multiplexer (Manifold Structure)

Radar Systems and Components

    Frequency-Modulated Continuous-Wave Radar

    Phase-Locked Loop Circuits