| 摘要: | 本論文以TSMC 0.18-μm CMOS與WIN 0.15-μm pHEMT製程，研製應用於Ka頻段之射頻前端接收機電路，內容為應用於Ka頻段之共平面波導低雜訊放大器、Ku頻段之轉導提升考畢茲壓控振盪器、Ku頻段之偏壓位準轉移壓控振盪器、K頻段與UNII頻段之低電壓操作壓控振盪器、K頻段之導納轉換壓控振盪器、Ka頻段之電流注入雙平衡吉爾伯特混頻器。 第一部分為共平面波導的低雜訊放大器，共平面波導的好處在可以減少基板厚度對電路特性的影響，並且使電路中的元件快速下地，減少走線效應，此放大器量測結果為：增益為13.9 dB，雜訊指數為4.3 dB，輸入反射損耗為8.5 dB，輸出反射損耗為14.6 dB，而輸入1 dB壓縮點為-3 dBm，三階截斷點為7 dBm，總功率消耗157.5 mW。 第二部分為四種壓控震盪器的設計，前兩種設計為搭配倍頻器的系統，第一種架構採用轉導提升的技巧，解決傳統傳統考畢茲電路不易起振的缺點，中心頻率為13.72 GHz，頻率可調範圍為812 MHz，輸出功率為-6 dBm ~ -3.6 dBm，離主頻1 MHz之相位雜訊為-113.8 dBc/Hz，振盪器本身消耗功率為4.1 mW，優化指數為-190.2 dBc/Hz；第二種架構採用偏壓位準轉移的方式，使電晶體維持在工作時候大多維持在飽和區以提升相位雜訊，中心頻率11.9 GHz，頻率可調範圍為656 MHz，輸出功率為-2.3 dBm ~ -0.4 dBm，離主頻1 MHz之相位雜訊為-111 dBc/Hz，振盪器本身消耗功率為4.5 mW，優化指數為-185.7 dBc/Hz。後兩種震盪器的設計為直接應用於混頻器，第一種架構採用源極-汲極耦合的變壓器，達到低電壓操作效能的壓控震盪器，本架構分別設計在兩個頻段，第一個設計在K頻段，中心頻率為22.85 GHz，頻率可調範圍為700 MHz，輸出功率為-9.1 dBm ~ -7.1 dBm，離主頻1 MHz之相位雜訊為-104.3 dBc/Hz，操作電壓為0.65 V，振盪器本身消耗功率為2.74 mW，優化指數為-187.02 dBc/Hz，第二個電路設計在UNII頻段，中心頻率為5.08 GHz，頻率可調範圍為280 MHz，輸出功率為-3.1 dBm ~ -0.6 dBm，離主頻1 MHz之相位雜訊為-114.18 dBc/Hz，操作電壓為0.4 V，振盪器本身消耗功率為2.1 mW，優化指數為-185.03 dBc/Hz；第二種架構採用導納轉換的技巧，將一般傳統的可變電容轉換成可變電感，有效降低變容器因高頻的損耗，使其在高頻容易起振，中心頻率為25.78 GHz，頻率可調範圍為290 MHz，輸出功率為-4.29 dBm ~ -3.48 dBm，離主頻1 MHz之相位雜訊為-104.2 dBc/Hz，振盪器本身消耗功率為7.8 mW，優化指數為-183.39 dBc/Hz。 第三部份為Ka頻帶之電流注入雙平衡吉爾伯特混頻器的設計，採用電流注入的機制，將流經本地源端的電流降低以保持電晶體開關切換速度，並且維持足夠射頻轉導級的電流以使放大輸入訊號，射頻的頻率為28 GHz，中頻的頻率為2.4 GHz，射頻頻率較本地端頻率高，量測結果顯示射頻訊號在28 GHz與中頻訊號在2.4 GHz返回損耗均為10 dB。本地端功率為2 dBm時得到最大轉頻增益為5.2 dB。射頻頻率3-dB操作頻寬6.6 GHz。中頻頻率3-dB操作頻寬為1 GHz。混頻器1 dB增益壓縮點為-4 dBm，三階截斷點為5 dBm；RF-LO、LO-IF及RF-IF隔離度均在30 dB以上。 This thesis describes the RF front-end receiver for Ka-Band applications which are implemented in WIN 0.15-μm pHEMT and TSMC 0.18-μm CMOS technologies. The implemented circuits include Ka-Band CPW LNA, Ku-Band gm-boosted Colpitts VCO, Ku-Band bias-level shifting VCO, K-Band with compared UNII-Band low voltage operation VCOs, K-Band admittance-transforming VCO, and Ka-Band current-bleeding double balanced Gilbert mixer. The Ka-Band CPW LNA is presented in the first section. The performance of the circuit may be varied by the variation of substrate thickness. However, this can be released by using CPW transmission line. Moreover, CPW transmission line lets the components of the circuit directly connect to the ground, avoiding the degradation caused by the unnecessary metal runners. The designed CPW LNA achieves the power gain of 13.9 dB, noise figure of 4.3 dB, input/output return losses of 8.5 dB, and 14.6 dB. The input 1 dB power gain compression point (P1dB) and the input third-order interception point (IIP3) occur at -3 dBm and 7 dBm, respectively. The total power consumption is 157.5mW. Four types of VCO are demonstrated in the second section. The former two types are indirectly applied for the mixer, needed to be series connected with the frequency doubler which doubling the output frequency. The frequency-doubled signal provided for mixer enables the frequency conversion. The first design is Ku-Band gm-boosting Colpitts VCO. By using the gm-boosting technique, the difficulty of the start-up condition in the conventional Colpitts oscillator can be relaxed. This design achieves the central frequency of 13.72 GHz, the tuning range of 812 MHz, and the output power range is from -6 to -3.6 dBm. The achieved FoM is -190.2 dBc/Hz which is calculated from the phase noise of -118 dBc/Hz at 1 MHz offset and the core power consumption of 4.1 mW. The second design is Ku-Band bias-level shifting VCO, letting the transistor working mostly in the saturation region by using bias-level shifting technique. This design achieves the central frequency of 11.9 GHz, the tuning range of 656 MHz, and the output power is the range of -2.3 dBm ~ -0.4 dBm. The FoM is high as -185.7 dBc/Hz which is calculated from the phase noise of -111 dBc/Hz at 1 MHz offset and the core power consumption of 4.5 mW. The latter two type VCOs are directly applied for the mixer. The K-Band low-voltage operation VCOs with the drain-source coupled transformer are proposed for UNII band applications. The K-Band design achieves the central frequency of 22.85 GHz, the tuning range of 700 MHz, and the output power range from -9.1 to -7.1 dBm. The FoM is high as -187.02 dBc/Hz which is calculated from the phase noise of -104.3 dBc/Hz at 1 MHz offset and the core power consumption of 2.74 mW. Another UNII-Band VCO design achieves the central frequency of 5.08 GHz, the tuning range of 280 MHz, and the output power range from -3.1 to -0.6 dBm. The FoM is high as -185.03dBc/Hz which is calculated from the phase noise of -114.18dBc/Hz at 1 MHz offset and the core power consumption of 2.1 mW. The K-Band admittance-transforming VCO is presented. By this technique, the conventional capacitance varactor is transforming to the variable inductance and also releases the high-frequency loss from of the varactor. This design achieves the central frequency of 25.78 GHz, the tuning range of 290 MHz, and the range of the output power from -5.05 to -2.75 dBm. The FoM is high as -183.2 dBc/Hz, which is calculated from the phase noise of --103.4 dBc/Hz at 1 MHz offset and the core power consumption of 7.8 mW. The Ka-Band current-bleeding double balanced Gilbert mixer is presented in the last section. The frequencies of LO and IF are selected at 25.6 GHz and 2.4 GHz, respectively. By using the current-bleeding technique, the current through the LO stage is reduced, keeping fast switching on and off of the LO stage transistor. And the input RF signal is still amplified before mixed with LO due to the constant current through RF stage. The measured RF and IF return losses are around 10 dB. The optimized power of LO drive is 2 dBm which result in a maximum conversion gain of 5.2 dB. The 3-dB bandwidths of RF and IF are high as 6.6 GHz and 1 GHz, respectively. The P1dB and IIP3 are -5 dBm and +4 dBm, respectively. The port to port isolations of RF-LO, LO-IF and RF-IF are better than 30 dB. |
