Direct extraction of GaAs FET equivolent circuit elements values from S-parameters

Kyung-Whan Yeom(염경환),Tae-Suk Ha(하태숙),Jung-Woong Ra(나정웅) 대한전자공학회 1986 대한전자공학회 학술대회 Vol.1986 No.12

주파수잠금회로(FLL)를 이용한 VCO의 위상잡음 개선 해석

염경환(Kyung-Whan Yeom),이동현(Dong-Hyun Lee) 한국전자파학회 2018 한국전자파학회논문지 Vol.29 No.10

FLL(Frequency-Locked-Loop: 주파수 잠금회로)은 주파수-검출기(frequency detector)를 사용하여 VCO의 위상잡음을 개선하는 부-궤환(negative feedback) 시스템이다. 본 논문은 FLL에 의한 VCO의 위상잡음의 이론적 분석을 새로이 제시하였다. 분석 결과, VCO의 위상잡음은 FLL 루프-대역폭 내에서는 주파수검출기와 루프-필터로 결정된 위상잡음을 좇아가며, 반면 루프-대역폭 밖에서는 VCO의 위상잡음이 그대로 나타나게 된다. 따라서 이론적 분석 결과를 바탕으로 VCO의 위상잡음을 최소화 하는 FLL을 설계할 수 있게 된다. 또한 실험을 통하여 이론적으로 분석된 위상잡음 결과는 검증하였다. A frequency-locked loop(FLL) is a negative-feedback system that uses a frequency detector to improve the phase noise of a voltage-controlled oscillator(VCO). In this work, a theoretical analysis of the phase noise of a VCO in an FLL is presented. The analysis shows that the phase noise of the VCO follows the phase noise determined by the frequency detector and the loop filter within the FLL loop bandwidth, while the phase noise of the VCO appears outside the loop bandwidth. Therefore, it is possible to design an FLL that minimizes the phase noise of the VCO based on the theoretical analysis results. The theoretical phase noise results were verified through experiments.

6-포트 회로망을 이용한 잡음 파라미터 측정

염경환(Kyung-Whan Yeom),압둘-라흐만(Abdule-Rahman Ahmed) 한국전자파학회 2015 한국전자파학회논문지 Vol.26 No.2

잡음 파라미터에 대한 정보는 저잡음 증폭기 설계에 있어 필수 불가결한 요소이다. 과거 잡음 파라미터는 임피던스 튜너와 잡음지수 측정기(Noise Figure Analyzer: NFA)를 사용 측정되어 왔다. 최근 저자들은 잡음 파라미터는 기계적으로 구동되는 임피던스 튜너 없이 8-포트 회로망 방법을 이용하여 측정될 수 있음을 보였다. 그러나 8-포트 회로망을 이용한 측정방법은 여전히 잡음원(noise source)을 이용하고, 측정의 복잡도를 증가시키는 면이 있다. 본 논문에서는 잡음원을 이용하지 않고, 잡음 파라미터를 측정할 수 있는 새로운 6-포트 회로망 방법을 제안한다. 6-포트 회로망 방법에 의해 이론적으로 알려진 잡음 파라미터를 갖고 있는 10-㏈ 감쇠기에 대해 측정하였으며, 측정된 잡음 파라미터 결과는 기존 8-포트 회로망 방법과 비교하였으며, 비교결과 8-포트 회로망 방법과 유사한 정확도를 갖는 것을 보였다. The information about noise parameters is essential in the design of low noise amplifier. In the past, the noise parameters were measured using an impedance tuner and noise figure analyzer. Recently, the authors proposed the method of measuring the noise parameters using the 8-port network without the aid of the mechanically driven impedance tuner. However, the 8-port method still requires the noise source and causes the complexity in the measurements. In this paper, a novel measurement method of the noise parameters without the noise source using 6-port network is proposed. Based on the proposed 6-port method, the noise parameters of 10 ㏈ attenuator whose noise parameters can be theoretically determined were measured and the measured noise parameters are compared with those measured using the previous 8-port network method. As a result, the accuracy of the measured noise parameters using 6-port network is found to be comparable to the previous 8-port network method.

디지털 오실로스코프와 Labview<SUP>TM</SUP>를 이용한 위상잡음 측정방법

염경환(Kyung-Whan Yeom),노진성(Jin-Seong Roh) 한국전자파학회 2021 한국전자파학회논문지 Vol.32 No.9

본 논문에서 Keysight사의 4-채널 10-bit 디지털 오실로스코프 MSO804A와 National Instruments사 Labview<SUP>TM</SUP>를 이용한 새로운 위상잡음 측정 방법을 제안한다. 정밀한 위상잡음 측정 계측기는 일반적으로 고가이며, 범용적이지 않은 반면, 디지털 오실로스코프는 범용적이다. 따라서 본 논문의 방법을 이용할 경우 저가이며, 용이하게 정밀 위상잡음 측정을 수행할 수 있게 된다. 구현된 위상잡음 측정방법의 평가를 위해 Keysight사의 함수발생기 33600A, SSG(synthesized signal generator) E8257D, Z-comm사의 VCO 3가지 SUT(source under test)에 대해 Keysight사의 SSA(signal source analyzer) E5052B로 측정된 위상잡음과 비교하였다. 주목할 것은 SUT 33600A, E8257D의 위상잡음은 범용 스펙트럼-분석기로 측정가능한 위상잡음보다 낮은 위상잡음을 갖는다. 비교 결과, 위상잡음의 차이는 약 ±3 dB 정도이며, E5052B로 측정된 위상잡음과 근접한 결과를 보인다. In this paper, we propose a novel phase noise measurement method using Keysight"s 4-channel 10-bit digital oscilloscope MSO804A and National Instruments" Labview<SUP>TM</SUP>. Precise phase noise measurement equipment is generally expensive and not universal, whereas digital oscilloscopes are universal. Therefore, via the method proposed in this paper, it is possible to perform precise phase noise measurements inexpensively and easily. To evaluate the proposed phase noise measurement method, the phase noises of three types of source under test (SUT), Keysight"s function generator 33600A, synthesized signal generator (SSG) E8257D, and Z-comm"s VCO were measured with Keysight"s signal source analyzer (SSA) E5052B, and compared to those measured using the presented method. Note that SUT 33600A and E8257D have lower phase noise than that a general-purpose spectrum analyzer can measure. The comparison results showed that the difference in phase noise is approximately ±3 dB, and the results are close to the phase noise measured with E5052B.

PIN 다이오드를 이용한 S-대역 고출력 경로선택형 SP4T 설계

염경환(Kyung-Whan Yeom),임평순(Pyung-Soon Im),이동현(Dong-Hyun Lee),박종설(Jong-Seol Park),김보균(Bo-Kyun Kim) 한국전자파학회 2016 한국전자파학회논문지 Vol.27 No.9

본 논문에서는 PIN 다이오드를 이용한 S-대역 고출력 경로선택형 SP4T 및 SP4T 구동회로의 설계를 보였다. 격리도 개선을 위하여 SP4T의 각 경로(path)는 직렬 및 병렬 PIN 다이오드 2개를 cascade하여 구성하였다. 설계된 SP4T 회로는 칩-형 PIN 다이오드와 박막(thin-film) 기법으로 제작된 20 mil AIN 기판을 사용하여 구현하였다. 또한, 설계된 SP4T의 구동회로는 1개의 multiplexer와 4개의 NMOS-PMOS push-pull 쌍을 이용하여 구성하였다. 온-웨이퍼 측정결과, 제작된 SP4T는 최대 삽입손실 1.1 ㏈, 최소격리도 41 dB의 특성을 보였다. 구동회로의 PIN 다이오드의 on-off, off-on 천이시간은 동일 PIN 다이오드의 패키지를 이용하여 시험하였으며, 모두 약 100 nsec 이하의 천이시간을 보였다. 150 W 입력 고출력 시험 결과, 격리도와 삽입손실은 동축 패키지의 손실 및 부정합을 고려하면 온-웨이퍼 측정결과에 준하는 결과를 얻었다. In this paper, the design of a PIN diode S-band transfer-type SP4T including its driver circuit is presented. Each path of the SP4T is composed of the cascade connection of series-shunt PIN diodes to improve the isolation performance. The SP4T is implemented using chip type PIN diodes and a 20 mil AIN substrate fabricated using thin film technology. The driver circuit for the SP4T is designed using a multiplexer and four NMOS-PMOS push-pull pair. From on-wafer measurement, the fabriacted SP4T shows a maximum insertion loss of 1.1 ㏈ and a minimum isolation of 41 dB. The time performance of the driver circuit is evaluated using the packaged PIN diodes with the identical PIN diode chip, and the transition time for on-off and off-on are below 100 nsec. For an input power level of 150 W, the measured insertion loss and isolation are close to those of the on-wafer measurement taking into consideration of the coaxial package mismatch and insertion loss.

An Extraction of Two-Port Noise Parameters From Measured Noise Powers Using an Extended Six-Port Network

Ahmed, Abdul-Rahman,Kyung-Whan Yeom Professional Technical Group on Microwace Theory a 2014 IEEE Transactions on Microwave Theory and Techniqu Vol. No.

<P>In this paper, we present a formulation for extracting the noise wave correlation matrix of a linear two-port device-under-test (DUT) from measured noise powers using a designed six-port network. The noise powers are measured using a conventional noise figure analyzer. The extracted noise wave correlation matrix can then be converted into conventional two-port noise parameters. The proposed measurement equipment is very simple and leads to a very low cost. The proposed method is experimentally verified through measurements of various DUT samples.</P>

Per-Channel Monitoring for Optical Transport Networks using Transparent OXCs

Ji Wook Youn,Kyung Whan Yeom,Bheom Soon Joo 대한전자공학회 2006 ITC-CSCC :International Technical Conference on Ci Vol.2006 No.2

A Full <tex> $Ku$</tex> -Band Reduced-Height Waveguide-to-Microstrip Transition With a Short Transition Length

Hyun-Seok Oh,Kyung-Whan Yeom IEEE 2010 IEEE transactions on microwave theory and techniqu Vol.58 No.9

<P>Asystematic design of a full Ku-band reduced-height waveguide-to-microstrip transition using commercial High Frequency Structure Simulator software is presented. The basic transition is composed of a shorted microstrip probe to a 50-Omega ridge waveguide. An impedance transformer necessary to adapt the 50-Omega ridge waveguide to a reduced-height waveguide was designed using multistage short-length ridge waveguides connected in cascade. The resulting transition length is 6.2 mm. The separately designed shorted microstrip probe transition and impedance transformer were combined and adjusted for full-Ku-band operation. The combined transition was fabricated and measured. The measured insertion and return losses are about 0.41 dB and below 15 dB for the full-Ku-band, respectively.</P>

Annexin A8 (ANXA8), a Metastasis Suppressor, is Down-Regulated by Epithelial Growth Factor (EGF)

김대곤 ( Dae Ghon Kim ),( Kyung Ran You ),( Hyo Jung Kim ),( Woo Sung Moon ),( Baik Whan Cho ),( Young Il Yeom ),( Sang Soo Kim ) 대한소화기학회 2004 대한소화기학회 추계학술대회 Vol.- No.-

An EM Tuning Procedure for Planar Filters Based on Individual Resonator Decomposition

Seong-Sik Yang,Kyung-Whan Yeom IEEE 2008 IEEE microwave and wireless components letters Vol.18 No.7

<P>Planar filters directly implemented by design formulas yield a distorted frequency response, especially at higher frequencies, due to dispersion and discontinuities. In this letter, an electromagnetic (EM) tuning procedure based on individual resonator decomposition for a fifth order stepped impedance resonator (SIR) filter is presented. The EM simulation of the SIR filter composed by the tuned resonators shows remarkable agreement with the design formula and requires no further tuning. The procedure is experimentally verified by comparing the measured and the simulation results.</P>