| 摘要: | 本篇論文分別利用tsmcTM 180 nm CMOS和穩懋半導體III-V族WINTM GaN 0.25 µm製程設計，論文中總共4顆晶片，其中CMOS部分為C/X頻段寬頻低雜訊放大器與接收機之研製，III-V族WINTM GaN 0.25µm製程為X頻段升頻式混頻器之研製。本篇論文研究主題主要為利用變壓器改善CMOS製程缺點所造成的轉導能力(gm)不足，藉此來對寬頻接收機進行最佳化設計與應用於海事雷達發射機中升頻式混頻器的隔離度問題改善。
第一顆寛頻低雜訊放大器係利用閘極與汲極變壓器實現輸入寬頻響應和前一級源極與本身汲極變壓器來拓展頻寬，並推導變壓器耦合對電感關係式，藉此改善高頻轉導值，實現寬頻低雜訊放大器的應用，使其應用於C/X頻段。量測結果顯示最高增益(|S21|)為15.6 dB，3-dB頻寬為5.1 – 11.5 GHz，最低雜訊為4.43 dB，線性度P1dB為 -10 ~ -13 dBm，IIP3為0 ~ -5 dBm，功耗為12.5 mW。
第二顆電路為C/X頻段低功耗寬頻接收機前端，第一級為寬頻低雜訊放大器，因為考慮到接收機的佈局問題，所以對第一顆寬頻低雜訊放大器佈局進行修改，之後考慮各個子電路間的阻抗相對關係，分析電流模態與電壓模態操作。整體接收機前端子電路分別為寬頻低雜訊放大器，第二級為寬頻巴倫是利用共振點來產生頻寬的架構，第三級為混頻器採用雙平衡式架構，最後為轉阻放大器(Trans-impedance Amplifier, TIA)，採用差動放大器的架構，本次設計兩級的轉阻放大器，通道頻寬則由RC回授來決定。量測結果顯示最高轉換增益(Conversion Gain)為31.5 dB， 3-dB頻寬為4.8 – 11 GHz，LO到RF隔離度大於70 dB，LO到IF隔離度大於45 dB，IF頻寬為125 MHz。線性度P1dB為-25 ~ -32 dBm與IIP3為-23.5 ~ -32.5 dBm，整體功耗為21.9 mW。
第三顆為GaN 0.25 µm製程的X頻段升頻式混頻器，為一個單平衡式架構的X頻段升頻式混頻器，並在本地震盪源與射頻輸出端接上馬遜巴倫，方便之後系統上的整合。量測結果顯示最高轉換損耗(Conversion Loss)為8.5 dB， 3-dB頻寬為8.5 – 10.8 GHz，LO到RF隔離度大於12.4 dB，輸出功率8.1 dBm，IF頻寬為1.1 GHz。線性度P1dB為12 ~ 22 dBm，整體功耗為0 mW。
第四顆為GaN 0.25µm製程的X頻段升頻式混頻器，但是為了改善第三顆的本地震盪源到射頻端隔離度的問題，在架構上為一個單端的升頻式混頻器加上倍頻器，先利用混頻器將頻率提升至5 GHz，接著利用倍頻器將頻率提升至計畫所需頻率。在基頻頻率上也將頻率改為150 MHz來進行改善本地震盪源頻率與射頻頻率的距離，此外在倍頻器輸出端還接上5 GHz傳輸線開路，使5 GHz訊號看到高阻來改善隔離度。模擬結果顯示最高轉換損耗(Conversion Loss)為4 dB， 3-dB頻寬為9.2 – 11.2 GHz，LO到RF隔離度大於33.5 dB，輸出功率4.1 dBm，IF頻寬為240MHz。整體功耗為630 mW。
;This thesis presents CMOS wideband low noise amplifier (LNA) and receiver (Rx) front-end in tsmcTM 180 nm CMOS technology and X-band mixers in WINTM 0.25 μm GaN/SiC technology. Four chips including C/X bnad wideband LNA, receiver, and two GaN up-conversion mixers were successfully designed, fabricated and verified. The main research topic is to design a wideband receiver using transformer feedback technique to overcome the limitation of low transconductance of (gm) in CMOS process. Meanwhile, the author developed the methodology to improve the isolation of up-converter mixer in radar transmitter.
The bandwidth extension technique applied in LNA was developed by source-drain transformer coupled between the first and second stages. The formula of the transformer with its self-inductance and coupling factor were derived and implemented in LNA. The measurement results show that the LNA achieved a maximum gain (S21) of 15.6 dB, a 3-dB bandwidth of 5.1 – 11.5 GHz, a lowest noise figure of 4.43 dB, a P1dB of -10 ~ -13 dBm and an IIP3 of 0 ~ - 5 dBm, power consumption of 12.5 mW.
The second circuit is a C/X band wideband low-power receiver front end. The receiver consists of a wideband LNA, a wideband balun, a double balanced mixer and a two-stage transimpedance amplifier (TIA). The channel bandwidth is determined by the RC feedback in TIA. The measurement results show the receiver achieved a maximum conversion gain of 31.5 dB, a 3-dB bandwidth of 4.8 – 11 GHz, an LO-to- RF isolation greater than 70 dB, an LO-to-IF isolation greater than 45 dB, and an IF bandwidth of 125 MHz. The P1dB is -25 ~ -32 dBm and the IIP3 is -23.5 ~ -32.5 dBm, power consumption of 21.9 mW, respectively.
The third circuit is an X-band GaN single-balanced (SBM) resistive up-mixer. Two lumped-element Marchand baluns are used in the LO and RF ports for convenient testing and further integration. The measurement results presents a minimum conversion loss of 8.5 dB, a 3-dB bandwidth of 8.5 - 10.8 GHz, an LO to RF isolation of greater than 12.4 dB, an output power of 8.1 dBm, and an IF bandwidth of 1.1 GHz. The P1dB is 12 ~ 22 dBm, power consumption of 0 mW, respectively. The fourth circuit is an X-band GaN up-mixer which adopted a single-ended up-converter mixer cascading a frequency doubler to overcome the isolation problem in conventional SBM. A 5 GHz quarter-wavelength open stub is added in the output of doubler to increase the LO-to-RF isolation. Meanwhile, IF frequency is selected high up to 150 MHz to relax the specification of filter design. The simulations show the receiver achieved a maximum conversion Loss of 4 dB, a 3-dB bandwidth of 9.2 – 11.2 GHz, an LO-to- RF isolation greater than 33.5 dB, and an IF bandwidth of 240 MHz, power consumption of 630 mW, respectively. |
