MMIC를 위한 PHEMT 제작 및 고이득-광대역 MMIC Distributed Amplifier의 설계

김성찬 東國大學校 大學院 2001 국내석사

In this dissertation, the PHEMT(Pseudomorphic High Electron Mobility Transistor), which is applicable to MMIC`s, was fabricated and then a high gain-broadband MMIC distributed amplifier was designed with the library of the fabricated PHEMT's. AlGaAs/InGaAs/GaAs PHEMT's were fabricated by unit processes such as ohmic contact processes with low resistance, T-gate processes by electron beam lithography and air-bridge processes to interconnect isolated electrodes and so on. The DC characteristics of PHEMT, which has 0.2 ㎛ of a gate length, 80 ㎛ of unit gate width and 4 fingers, are 0.9 V of knee voltage, - 2.5 V of pinch-off voltage, 103.3 mA of drain saturation current, 322.8 mA/mm of drain current density and 231.5 mS/mm of maximum transconductance at V_(gs) = - 1.2 V and V_(ds) = 3 V. RF characteristics are 6.5 dB of S_(21) gain and 13.5 dB of MAG(Maximum Available Gain) at 20 GHz. The current gain cut-off frequency(f_(T)) is 63 GHz and the maximum oscillation frequency(f_(max)) is 150 GHz. A high gain-broadband MMIC distributed amplifier was designed by cascaded single section distributed amplifier configuration. A designed MIMIC amplifier has higher S_(21) gain than the common distributed amplifier with the same number of active devices. From the simulated results, S_(21) gain of DC ~ 20 GHz bandwidth was 15.6 dB and flatness was ± 0.9 dB and input and output reflection coefficient were lower than -8 dB. The simulated gain of the designed high gain-broadband MMIC distributed amplifier with the chip size 2.0 × 1.2 ㎟ shows an improvement 7.3 dB Of S_(21) gain compared with those of conventional distributed amplifier.

X-band용 MMIC 전력증폭기에 관한 연구

이성대 동국대학교 대학원 1999 국내석사

In this paper, a MMIC power amplifier for X-band was designed and fabricated using the library of active and passive devices for design of MMIC power amplifier. AlGaAs/InGaAs/GaAs PHEMT's were used for active devices of MMIC power amplifier. The PHEMT's were fabricated by unit processes such as ohmic contact process with low resistance, T-gate electron beam lithography process and air-bridge process for interconnection of isolated electrodes. The OC characteristics of PHEMT, which has 0.35 ㎛ of gate length, 40 ㎛ of unit gate width and 4 gate fingers, are 1.3 V of knee voltage, -1.5 V of pinch-off voltage, 249.58 mA/mm of drain current density and 206.44 mS/mm of maximum transconductance at Vgs = -0.6 V and Vds = 2.75 V. And the RF characteristics are 5.04 dB of S_(21) gain and 13.7 dB of MAG at 10 GHz. The current gain cut-off frequency is 35 GHz and maximum oscillation frequency is 60 GHz. The DC and RF characteristics of PHEMT with 0.35 ㎛ of gate length, 80 ㎛ of unit gate width and 8 gate fingers are 1.5 V of knee voltage, -1.75 V of pinch-off voltage, 182.44 mA/mm of drain current density and 128.52 mS/mm of maximum transconductance at Vgs = -0.8 V and Vds = 2.75 V, 11.3dB of S_(21) gain and 15.5 dB of MAG at 10 GHz, 48 GHz of current gain cut-off frequncy and 65 GHz of maximum oscillation frequency. Also, the passive device library using measured results of fabricated passive devices such as Ti thin film resistors, rectangular spiral inductors and MIM capacitors to circuit matching was made. The MMIC power amplifier for X-band was designed and fabricated by active and passive devices library. The fabricated MMIC power amplifier shows that S_(21) and S_(11) are 14.804 dB and -29.577 dB at 8.18 GHz, respectively. The chip size is 1.86 ×1.29 ㎟.

GaAs MESFET을 이용한 DSRC용 5.8GHz 대역 LNA/Mixer MMIC 설계 및 구현

문태정 東亞大學校 大學院 2002 국내박사

본 논문에서 GaAs MESFET을 사용하여 지능형교통시스템(ITS)의 단거리전용통신(DSRC)을 위한 차량탑재장치(OBE) 시스템의 수신기 전단부(RFE)를 구성하는 5.8GHz 대역의 저잡음 증폭기(LNA)와 주파수 혼합기(Mixer)를 최적으로 설계하고 MMIC로 구현하였다. 설계된 회로는 0.5㎛ GaAs MESFET 기반의 능동소자와 나선형 인덕터, MIM 커패시터, 저항으로 구성되는 수동소자를 포함하며, ETRI의 MMIC 공정을 통해서 성공적으로 제작하였다. 칩크기는 1.2mm×l.4mm이다. 그리고 제작된 MMIC를 측정하기 위하여 전송선을 고려하여 PCB와 지그(JIG)를 설계 및 제작하였고, 시험장비를 이용하여 측정하였으며, 설계값과 측정값을 비교하였다. 본 논문에서 설계한 LNA는 2단 구조로 구성되어 있고, 모든 단은 자기바이어스 방식으로 연결하여 DC 3V의 단일 공급전압으로 동작이 가능하게 하였다. 설계한 LNA의 첫째단과 둘째단은 각각 잡음정합과 선형성에 초점을 두어 설계하였다. 그리고 본 논문에서 설계한 믹서는 DC 3V의 단일 공급전압을 사용하기 위해 공통소스 자기바이어스 회로를 가지는 캐스코드 모양의 Dual-gate 구조의 믹서이다. 믹서에서 RF와 LO의 중심주파수는 각각 5.8GHz와 5.84GHz이고, 두 신호의 주파수 혼합에 의한 중간주파수(IF)는 40MHz이다. 제작된 MMIC의 측정결과, 중심주파수가 5.8GHz에서 LNA의 이득이 13.4dB, 잡음지수가 1.94dB, IMD가 -48.67dBc, IIP3가 3dBm, 입력반사손실이 -l8dB, 출력반사손실이 -13.3dB이다. LNA의 전체 소비전류는 18.6mA이고, 제작된 회로의 실제 크기는 두개의 능동소자와 매칭회로와 두개의 드레인 바이어스 회로를 포함하여 1.2mm×0.7mm이다. 5dBm의 LO 전력에서 믹서의 변환이득은 4dB, 잡음지수가 7.4dB, IMD가 -41.05dBc, IIP3가 4.5dBm, RF 입력반사손실이 -l6dB, LO 입력반사손실이 -10.3dB, IF 출력 반사손실이 -10.2dB, LO-to-RF isolation이 -26.8dB, LO-to-lF isolation이 -3ldB이다. 믹서의 전체 소비전류는 5.58mA이고, 제작된 회로의 실제 크기는 두개의 능동소자와 매칭회로와 DC 회로를 포함하여 1.2mm×0.7mm이다. 본 연구로부터 구현된 LNA/Mixer MMIC는 NF, IMD, IIP3, 단자간 격리도 면에서 좋은 결과를 얻을 수 있었고, GaAs MESFET을 사용하여 지능형 교통시스템의 단거리전용통신을 위한 차량탑재장치내의 5.8GHz 대역 RF 소자들의 MMIC 구현이 충분히 효과적이었음이 확인되었다. 또한 MMIC 공정과정과 더불어 칩을 조립할 때 패키지의 기생적인 파라메터들과 Bonding wire부터 발생되는 부가적인 인덕턴스의 영향으로 인해 MMIC의 동작특성이 감소될 수 있음을 확인하였다. 그러므로 만약 MMIC의 공정과정이 잘 제어되고, MMIC를 설계시 기생적인 패키지 파라메터를 고려할 수 있다면, DSRC를 위한 5.8GHz 대역 LNA/Mixer MMIC를 성공적으로 개발될 수 있을 것으로 사료된다. 끝으로 본 연구를 통해 설계한 자료가 5.8GHz 대역 MMIC의 설계 및 개발에 활용될 수 있을 것으로 기대된다. In this paper, we have optimally designed and implemented the monolithic microwave integrated circuits(MMIC) of the low noise amplifier(LNA) and mixer operating at 5.8GHz band, which are supposed to be used in the receiver front-end(RFE) of on-board equipment(0BE) system of Dedicated Short Range Communication(DSRC) for intelligent transportation system (ITS). The designed circuit has been successfully fabricated with the MMIC process of ETRI based on the 0.5㎛ GaAs MESFET as the active elements, and on the spiral inductors, MIM capacitors and resistors as the passive lumped elements. The chip size was 1.2㎜×1.4㎜. And we have designed and made JIG and the printed circuit board(PCB) in consideration of transmission line in order to measure the performance of the MMICs, which were measured by network analyzer(Anritsu 37397A, HP8757D), noise figure meter(Agilent 8970B) and spectrum analyzer(Agilent 8565EC), and analyzed by comparing them with the designed values. The LNA MMIC consists of 2-stage structure and the self-biasing was employed in all stages, enabling a single supply voltage of DC 3V to be used. The first stage of LNA was designed with the focus on noise matching while the second stage on linearity. The mixer MMIC adopted the dual-gate structure with a kind of cascode type employing common-source self-biasing circuits for a single supply voltage of DC 3V. For the mixer, the RF and the LO center frequencies were chosen to be 5.8GHz and 5.84GHz, respectively. The intermediate frequency (IF) resulted from mixing two signals was 40MHz. The gain of the LNA at center frequency 5.8GHz was measured to be 13.4dB, noise figure(NF) to be 1.94dB, intermodulation distortion(IMD) to be -48.67dBc, input third-order intercept point(IIP3) to be 3dBm, and input return loss(S_(11)) and output return loss(S_(22)) to be -18dB and -13.3dB, respectively. The total consumption current of LNA was 18.6mA, and the actual dimension of the fabricated MMIC was 1.2㎜×0.7㎜, including two active devices, matching circuits, and two drain bias circuits. The conversion gain of the mixer at the LO power of 5dBm is 4dB, noise figure 7.4dB, intermodulation distortion -41.05dBc, input third-order intercept point 4.5dBm, RF input return loss -16dB, LO input return loss -10.3dB, IF output return loss -10.2dB, and LO-to-RF isolation and LO-to-IF isolation is -26.8dB and -31dB, respectively. The total consumption current of the mixer was 5.58mA, and the actual dimension of the fabricated circuit was 1.2㎜× 0.7㎜, including two active devices, matching circuits, and DC bias circuits. The MMIC integrated with LNA and Mixer together produced good performance in terms of NF, IMD, IIP3, port-to-port isolations. From these results, it has been confirmed that MMIC implementation based on GaAs MESFET of RF devices operating at 5.8GHz-band was successful. However, the performance of the MMICs was found to be slightly degraded due to the influence of the parasitic components associated with the package as well as with the additional inductances originated from bonding wires. Thus, if the MMIC fabrication process is well-controlled, and the parasitic components are considered in the design of the MMIC circuit, it is believed that the LNA/Mixer MMIC operating at 5.8GHz band can be successfully realized.

단거리전용통신용 5.8GHz ASK 변조기 및 LNA MMIC 설계

이일섭 東亞大學校 大學院 2000 국내석사

단거리전용통신 시스템의 차량탐재장치(OBE)에 사용하기 위한 5.8GHz ASK 변조기와 LNA MMIC를 ETRI 0.5㎛ MESFET library를 사용하여 설계하였다. ASK 변조기 MMIC는 인접채널전력을 줄이기 위하여 3V 단일 전압 드레인 제어 변조회로로 설계하였다. 0.7-3V의 넓은 선형변조영역과 57dB이상의 우수한 on/off 특성을 가졌고, 칩 면적은 1㎜×l㎟이다. LNA MMIC는 2단 cascaded 증폭기 구조로 설계하였고, 5.8GHz에서 이득은 13.6dB, 잡음지수는 1.2dB를 가졌고, 칩 면적은 1.2㎜×1.3㎟이다. We have designed ASK modulator LNA MMIC operating at 5.8GHz for OBE(on-Board Equipment)used in AGPS(Automatic Gate Passing System). ASK modulator MMIC employing single-voltage drain-controlling modulator circuit was designed to be able to operate at 3V in order to decrease ACP(Adjacent Channel Power). This circuit exhibits a broad linear modulation range of 0.703V and an excellent on/off characteristics of the larger than 57dB. And a low noise amplifier MMIC has been also designed with 2-stage cascaded amplifier configuration. The gain was 13.6㏈ and NF 1.2dB at 5.8GHz. The layouts of two MMICs were designed by using ETRI 0.5㎛ MESFET library. The chip sizes were 1mm×1mm and 1.2mm×1.3mm, respectively.

DSRC적용을 위한 ASK-PA/콜피츠형 발진기 MMIC 설계 및 구현

김병국 東亞大學校 大學院 2003 국내석사

본 논문은 GaAs MESFET을 사용하여 ITS의 단거리 전용통신(DSRC)을 위한 차량탑재장치인 OBE의 송신단중 ASK와 Power Amplifier를 단일 칩으로 설계 제작하였고, 국부 발진기용으로 콜피츠 발진기를 설계하였다. 설계된 회로는 GaAs 기판 위에 Depletion/ Enhancement MESFET과 수동소자인 나선형 인덕터, MIM 커패시터, 저항으로 구성되고, ETRI의 MMIC 공정을 통하여 구현하였다. 그리고 제작된 MMIC를 측정하기 위하여 PCB와 지그(JIG)를 설계 및 제작하였고, 시험장비를 이용하여 측정하여 설계값과 측정값을 비교하였다. 첫째, ASK-PA의 전단은 ASK 변조기로서 회로의 복잡도를 줄이기 위하여 직접변조방식을 채택하였고, 인접채널간섭을 줄이기 위하여 3V 단일전압 드레인 제어변조회로로 설계되었으며, 높은 on/off 비와 입력 임피던스 정합을 위해 변조기 첫단을 전치변조기로 설계하였다. 후단의 전력증폭기는 1단은 구동용, 2단은 전력증폭용으로 2단으로 구성하였으며, 증폭기의 바이어스 방법은 전압분배 바이어스와 3V 단일공급전원에서 동작하도록 설계하였다. 설계된 전력증폭기는 AB급으로 동작하게 하였다. 설계된 ASK와 전력증폭기는 공액 매칭구조로 서로 연결하였으며, 시뮬레이션 결과 54.7dB의 On/Off 비 변조 특성과 11.3dBm이하의 송신출력, PAE 6.26%의 결과를 얻었다. 구현된 ASK변조기-전력증폭기의 실제 크기는 5개의 능동소자와 매칭회로와 DC bias 회로를 포함하여 1.2mm×1.4mm이다. 측정결과는 data 신호가 on일때 이득은 20.63dB, 최대출력 파워의 지표인 P1dB는 7.8dBm로 나타났으며, data off 일때의 출력 파워는 -30.53dBm이였다. 이득은 모이실험 결과와 10dB 이상 차이가 있음을 확인하였고, on/off 비가 50.86dB로 우수함을 확인을 하였다. 둘째, 송신단의 주파수 상향 변환을 위한 5.8GHz 국부발진용으로 콜피츠 발진기를 설계하였다. 설계된 5.8GHz 콜피츠 발진기는 부성저항부, 바이어스부, LC공진부, 증폭회로부, 버퍼회로부로 구성되어 있다. 설계된 콜피츠 발진기의 발진가능성을 소신호 모델 모의실험을 통해 5.861GHz에서의 발진가능성을 확인하였으며, 대신호 모델 모의실험에서 버퍼에서의 출력에서 기준주파수 5.8GHz에서의 출력파워가 -2.4dBm, 두번째 고조파 성분인 11.6GHz에서의 출력 주파수가 -18.08dBm을 확인하였다. 본 논문에서 GaAs MESFET을 사용하여 ITS용의 단거리전용통신을 위한 OBE 내의 5.8GHz 대역 RF module의 MMIC 실현 가능성을 확인하였다. 또한 MMIC 공정과정과 더불어 칩을 조립할 때 패키지의 기생 커패시터와 본딩 와이어의 설계회로와의 길이 차이로 인하여 매칭의 틀어짐으로 인해 MMIC의 동작특성이 감소될 수 있음을 확인하였다. 그러므로 만약 MMIC 의 공정과정이 잘 제어되고, MMIC 설계시 기생 파라미터와 와이어 본딩의 특성을 충분히 고려 하게 된다면 DSRC용 5.8GHz 대역의 송신단 ASK변조기-전력증폭기와 국부 발진용 콜피츠 발진기 MMIC를 성공적으로 개발될 수 있을 것으로 사료된다. 끝으로 본 연구를 통해 설계된 자료가 5.8GHz 대역 MMIC의 설계 및 개발에 활용될 수 있을 것으로 기대된다. In this paper, we have designed and implemented the monolithic microwave integrated circuits(MMIC) of ASK modulator-Power Amplifier one chip and Colpitts type oscillator, which would be supposed in transmitter of On-Board Equipment(OBE) of Dedicated Short Range communication(DSRC) used for intelligent transportation system(ITS). The designed circuit has been fabricated by the MMIC process of ETRI based on the 0.5㎛ GaAs MESFET as the active elements, and the spiral inductors, MIM capacitors and resistors as the passive lumped elements. The chip size is 1.2mm×1.4mm. And we have designed and made JIG and the printed circuit board(PCB). We also designed and fabricated PCB and JIG to measure MMIC devices, and compared designed value with measured value using analyzer measurements. First, The front stage of ASK modulator-Power Amplifier as ASK modulator adopted direct modulation method in order to simplify the transmitter circuit configuration, and designed to apply a single supply voltage of 3V to the drain in order to decrease ACP(Adjacent Channel Power). One-stage of modulator was employed to obtain large On/Off ratio and input impedance matching. The power Amplifier of next stage was composed of two stage: the driving stage and the amplifying stage. It was also designed to use a single supply voltage of 3V, which was achieved by the divided voltage bias circuit. The designed power Amplifier is operated by AB class. The designed ASK modulator-Power Amplifier were connected each other as conjugate matching structure. The simulation results showed On/Off ration of 54.7dB, output power less than 11.3mW, PAE of 6.26%. As a results of measurement, we confirmed that the gain is 20.63dB, P1dB as basis of maximum output power is 7.8dBm when data signal is on, and the gain is -30.53dB on data off. We also confirmed that the gain is 10dB less than simulation result and On/Off ratio is obtained good result as 50.86dB. Second, We designed Colpitts oscillator as 5.8GHz local oscillator for frequency upper conversion of transmitting stage. The designed 5.8GHz Colpitts oscillator is composed with negative resistance part, bias part, LC tank part, Amplify circuit part, buffer circuit part. We confirmed oscillation possibility of designed Colpitts oscillator at 5.861GHz through small signal model experiment and that output power at fundamental frequency 5.8GHz is -2.4dBm, output frequency at second harmonic frequency 11.6GHz is -18.08dBm where the output of buffer through large signal model. In this paper, We confirmed MMIC realization possibility of 5.8GHz band RF module within OBE for DSRC of ITS. We also confirmed active characteristics of MMIC is reduced because MMIC manufacturing process as well as twist of matching by length difference between parasitic capacitance of package and bonding wire when fabricating the chips. So, We can successfully develop transmission stage of 5.8GHz band for DSRC ASK modulator-Power Amplifier and Colpitts oscillator MMIC for local oscillator if manufacturing process has been controlled well, and parasitic parameter and characteristics of wire bonding have been sufficiently considered. Finally, We hope that this paper can be applied to design and development of 5.8GHz band MMIC.

DSRC 적용을 위한 송신단 MMIC 설계 및 구현에 관한 연구

허혁 東亞大學校 2003 국내박사

본 논문은 GaAs MESFET을 사용하여 ITS의 단거리전용통신(DSRC)을 위한 차량탑재장치인 OBE의 송신단중 ASK 변조기와 전력 증폭기를 각각 설계 제작하였고. 또, ASK 변조기와 전력증폭기를 One-Chip화 하여 MMIC로 구현하였다 설계된 회로는 GaAs MESFET기판의 능동소자와 나선형 인덕터, MIM 커패시터, 저항등의 수동소자로 구성되고, ETRI의 MMIC 공정으로 제작하였다. 그리고 제작된 MMIC를 측정하기 위하여 PCB와 지그(JIG)를 설계 및 제작하였고, 시험장비를 이용하여 측정하였으며 설계값과 측정값을 비교하였다. 첫째, ASK 변조기는 회로의 복잡도를 줄이기 위하여 직접변조방식을 채택하였고, 인접채널간섭을 줄이기 위하여 3V 단일전압 드레인 제어변조회로로 설계되었으며, 높은 On/off 비와 입력 임피던스 정합을 위해 변조기 첫단을 전치변조기로 설계하였다. 설계된 ASK 변조회로의 시뮬레이션 결과로서 0.7-3V 에 이르는 넓은 선형변조영역과 55㏈의 높은 On/off 비 특성을 얻었으며, 또한 실제 제작된 MMIC의 측정결과에서도 0.7-3V의 넓은 선형 변조영역과 40㏈의 On/Off 비 특성을 얻었다. 제작된 칩 면적은 1.0mm×1.0mm이었다. 둘째, 전력증폭기는 1단은 구동용, 2단은 전력증폭용으로 2단으로 구성하였으며, 증폭기의 바이어스 방법은 전압분배 바이어스와 3V 단일공급전원에서 동작하도록 설계하였다. 설계된 전력증폭기는 AB급으로 동작하게 하였으며, 이득 15.7㏈, PAE 7.4%, 송신출력 10㎽이하의 값을 얻었다. 설계된 칩면적은 1.0mm×0.9mm이었다. 세째, ASK 변조기와 전력증폭기를 One-Chip화 하였다. 기존에 제작된 전력증폭기의 문제점이었던 와이어 본딩, 외부소자 연결, 비아 홀 등에 의한 매칭의 파괴를 보상하기 위하여 소스단에 여러 개의 와이어 본딩을 병렬로 연결하여 설계하였다. 시뮬레이션 결과 56d㏈의 On/Off 비 변조 특성과 11.3㎽ 이하의 송신출력, PAE 6.26%의 결과를 얻었다. 본 연구에서 구현된 ASK 변조기와 전력증폭기는 지능형 교통 시스템의 단거리전용통신을 위한 차량탑재장치에 적용할 수 있음을 확인할 수 있었고, 또한 MMIC 공정과정의 오차와 더불어 칩을 조립할 때 패키지의 기생 파라메터들, 그리고 본딩 와이어에서 발생되는 부가적인 인덕턴스의 영향으로 인해 MMIC의 동작 특성이 감소됨을 확인 할 수 있었다. In this paper, we have designed and implemented the monolithic microwave integrated circuits (MMIC) of the ASK modulator, Power Amplifier and One-Chip integrating the ASK Modulator and with Power Amplifier, which would be employed in transmitter of on-board equipment(OBE) of Dedicated Short Range Communication(DSRC) used for intelligent transportation system (ITS). The designed circuit has been successfully fabricated by the MMIC process of ETRI based on the 0.5㎛ GaAs MESFET as the active elements, and on the spiral inductors, MIM capacitors and resistors as the passive lumped elements. And we have designed and made JIG and the printed circuit board(PCB) as well in order to investigate the performance of the MMICs, which were measured by network analyzer, noise analyzer and examined analyzer, and analyzed by comparing them with the theoretical values. ASK modulator MMIC circuit adopted the direct modulation method in order to simplify the transmitter circuit configuration, and it was designed to apply a single supply voltage of 3 V to the drain in order to decrease ACP(Adjacent Channel Power). One-stage of modulator was employed to obtain large On/Off ratio and input impedance matching. The simulation results of ASK modulator MMIC showed a broad linear modulation range from 0.7V to 3 V and high On/Off ratio over 55㏈. The measured results produced the linear modulation range from 0.7V to 3V as the simulation meanwhile the On/Off ratio was reduced to 40㏈. The chip size was l.0mm by 1.0mm. Power Amplifier MMIC was composed of two stage ; the driving stage and the amplifying stage. It was also designed to use a single supply voltage of 3V, which was achieved by the divided voltage bias circuit. Power Amplifier MMIC operated at AB class with Power Gain of 15.7㏈, PAE of 7.4% and output power less than 10㎽. The chip size was 1.0mm by 0.9mm. MMIC integrating ASK Modulator with Power Amplifier adopt several wire bonding pads to source stage in parallel in order to compensate mis-matching caused by wire bonding pad and via holes. The simulation results showed OdOff ratio of 56㏈, output power less than 11.3㎽, PAE of 6.26%. With these results, it is most likely possible that the MMICs implemented in this paper can be applied to OBE system of DSRC for ITS. However, the performance of the MMICs were found to be slightly degraded due to the influence of the parasitic components associated with the package as well as with the additional inductances originated from bonding wires.

Design and Fabrication of AlGaN/GaN-on-Si FETs for Ka-band MMICs

김동환 서울대학교 대학원 2018 국내박사

As the power amplifiers (PAs) become increasingly important for use in communication of wireless and satellite, and military applications, a high operation frequency bands are highly desired for microwave transistors and monolithic microwave integrated circuits (MMICs) due to the tremendous usage of bandwidth. Since the performance of current Si, GaAs, or InP technology does not satisfied next-generation, high-power amplifiers with their inherent material limitation, GaN based materials have been intensively explored for past few decades in the aspects of their excellent properties, such as wide bandgap and high electron saturation velocity. Especially, GaN-on-Si technology is of particular interest to radio frequency (RF) industry because of the potential for low cost and the large volume of wafer production. This work firstly introduced the overall key process technologies of GaN millimeter-wave (mmw) device including ohmic contact, isolation, passivation, and gate process. For passivation process, we have decided the thickness of dielectric layer considering both mitigations of peak electrical field at the gate edge and degradation of small-signal characteristics due to an increase of parasitic capacitances. Also, gate structure was taken account of minimizing parasitic capacitances with short gate field-plate. The gate metal stack for millimeter-wave applications was suggested nickel and gold with molybdenum as diffusion barrier metal to achieve good thermal stability on RF performances. The final goal of this work was improvement of output power of Ka-band GaN HEMT device and MMIC PA using the proper AlGaN/GaN heterostructure on Si substrate with several technologies that dealt with modifying GaN epitaxial structure, applying high-k dielectric on passivation process, and employing recessed metal-insulator-semiconductor (MIS) structure on gate instead of metal-semiconductor (Schottky) based on above overall processes of GaN mmw device. Using AlGaN/GaN heterostructure with undoped GaN buffer demonstrated better small-signal and large-signal characteristics at 18 GHz load-pull measurement which indicated the direction of epitaxial structure for mmw application. The MIS gate structure with high-k dielectric satisfied low gate leakage current and low current collapse at a time resulted in higher output power than the conventional Schottky gate structure. To demonstrate 26.5~27 GHz GaN MMIC PA, we also optimized each fabrication process of passive elements including NiCr thin film resistor (TFR), metal-insulator-metal (MIM) capacitor, and coplanar waveguide (CPW) transmission line. Finally, the fabricated MMIC PA with employing thin SiNx interface layer for dual MIS structure, ion implantation for device isolation, and field-plated Y-gate for low gate resistance and parasitic capacitance achieved higher output power without degradation of gain at higher operation voltage than conventional Schottky gate at higher center frequency. The front process technologies we developed in this work showed the potential of GaN-on-Si technology for mmw application with watt-level output power. The packaging with good thermal management and design method of MMIC for the higher output power and PAE (power-added efficiency) might improve the performance of GaN-on-Si MMIC PA.

Q-Band MMIC 믹서의 설계

문주영 서강대학교 대학원 2003 국내석사

본 논문에서는 Half-LO 주파수를 사용하는 Double Conversion 믹서를 MMIC로 설계하였다. 제안된 믹서는 RF/LO의 격리도를 향상시키기 위해서 Double Conversion 방식을 사용하였으며 두 개의 HEMT를 이용하여 Half-LO 신호를 인가하였을 때 second IF 신호를 발생시킨다. HP사의 비선형 Simulation tool 인 ADS(Advanced Design System)을 이용해 Harmonic Balance 해석과 Momentum 해석을 통하여 정합회로를 구성하였다. 제안된 믹서는 일반적인 믹서와 비교하여 낮은 LO 전력과 Half-LO 주파수가 필요하다. 19.6 GHz에서 0 dBm 의 LO 신호를 인가하였을 때 변환손실은 13 dB , 35 dB 이상의 RF/LO 격리도를 얻었다. In this paper, the double conversion gate mixer using a half-LO frequency is described at 40 GHz Band. The proposed mixer uses two PHEMTs excited by a single LO signal of half-LO frequency in order to generate the second IF signal. That is, the LO signal having the half-LO frequency derives the first mixer and the second mixer as a normal single gate mixer. The proposed mixer requires not only half of the normal LO frequency, but also lower LO power than the conventional subharmonically pumped mixers. The MMIC was tested at 40 GHz and pumped by 0 dBm of LO power at 19.6 GHz. As result the conversion loss of 13 dB and over 35 dB of RF/LO isolation characteristics are obtained.

SiGe HBT를 이용한 C-Band WLAN용 RF Front End MMIC 설계 및 제작

배정형 안양대학교 대학원 2004 국내석사

본 논문에서는 C-Band WLAN용 RF수신 모듈인 저 잡음증폭기(LNA), 하향 주파수 혼합기 (Down Mixer), 전압제어 발진기(VCO)를 SiGe HBT MMIC로 설계, 제작, 측정, 분석 하였다. 내부 연결선을 ground shield micro strip Line 구조로 하여 절연성이 약한 실리콘 기판의 누설 전류를 줄이도록 하였다. 국내의 Tachyonics사와 세계적 수준의 STMicroelectronics사의 SiGe HBT MMIC 공정을 이용한 MMIC의 제작은 C-Band 대역의 SiGe HBT MMIC 국내 제작 가능성을 보여주었다. Common-emitter와 emitter-follower로 구성된 2단 저 잡음 증폭기는 4.7 dB 의 잡음 지수를 얻었으며, by-pass 기능이 포함된 common-emitter구조의 2 단 증폭기는 13.2 dB의 선형 전력 이득을 얻었다. 차동 형 전압제어 발진기로 구동시킨 Gilbert 혼합기 구조의 이중평형 하향 주파수 혼합기는 3 dB의 차동 변환 이득을 얻었다. 내부에 emitter-follower 완충증폭기가 포함된 차동 전압 제어 발진기는 4.7 GHz에서 -2.3 dBm 의 출력전력을 얻었다. In this paper, Silicon germanium hetero-junction bi-polar transistor (SiGe HBT) monolithic microwave integrated circuits (MMIC) i.e. low noise amplifier (LNA), double balanced down converting mixer (down-mixer), voltage controlled oscillator (VCO), are designed, fabricated, measured and analyzed as components of RF receiver module for the C-band wireless local area network(WLAN) applications. Inter-connection lines are established over ground shield micro strip structured layer to reduce the leakage current of low resistive silicon substrates. The SiGe HBT MMIC foundries provided by Tachyonics and ST Microelectronics are used to demonstrate the feasibilities of domestic and world-wide SiGe HBT MMIC technology for the C-band applications. A common-emitter LNA is cascaded with an emitter- follower to achieve a 4.7 dB noise figure. The cascade two stage common-emitter LNA with by-pass capability achieves a linear gain of 13.2 dB. The Gilbert type double balanced down-mixer which is pumped by the differential VCO produces a 3 dB conversion gain. The differential VCO has an internal emitter follower buffer to generate a single ended output power of -2.3 dBm at 4.7 GHz.

10GHz 통신 시스템을 위한 MMIC회로 설계

전동빈 江原大學校 大學院 1996 국내석사

본 논문에서는 10GHz급 통신시스템을 위한 MMIC 설계기법을 제시하였다. 설계된 회로의 적용 목적은 초고속통신시스템의 수신단이고, 회로의 종류는 전치증폭기1 제한증폭기, 자동이득조절증폭기의 3 종이다. 최적의 MMIC 설계를 위하여 기생성분의 모델링과 이틀 포함한 회로시뮬레이션을 수행하였고 전자기 시뮬레이션 데이타를 이용하여 레이아웃 단계의 디자인룰을 결정하였다. MMIC에 사용될 수동소자를 설계하고 전자기 시뮬레이션결과와 측정치를 비교하여 수동소자의 신뢰도 및 시뮬레이션 데이타의 적합성을 검증하였다. 이상의 과정을 통하여 MMIC에 부가되는 기생성분을 최소화 하였으며 최적의 실장(Packaging)을 위한 레이아웃을 수행하였다. This thesis is presents a MMIC(Mono1ithic Microwave Integrated Circuit) study for a high speed transmission system. The objective system of this study is a MMIC receiver chip-set of 10GHz optical transmission system. The MMIC chips are composed of a preamplifier, a limiting amplifier and a automatic-gain-controll(AGC) amplifier. To get an optimal design, a parasitis modeling and a circuit simulation including modeled parasitics were performed and layout design rule was determinded using electro-magnetic(EM) simulation data. The passive clements for MMIC were designed also, whose confidence was verified by the comparison of EM simulation & measured data. Using this study, a parasitics minimization and an optimal layout design for packing are obtained.