V頻段微型化混頻器之研製

Design and Implementation of V-Band Miniature Mixers

連婉茹(Wan-Ru Lian)

指導教授 ： 邱煥凱

國立中央大學/資訊電機學院/電機工程學系/碩士(2006年)

摘要

本論文主要研究毫米波V頻段微型化混頻器，論文內混頻器主要架構為次諧波電阻性混頻器、次諧波共平波導二極體混頻器與次諧波鏡像抑制混頻器，頻率操作在V頻段，其中次諧波鏡像抑制混頻器包含一微小化馬遜平衡器設計。以上電路皆是以WIN 0.15 μm pHEMT製程研製。
次諧波電阻性混頻器主要是利用一對汲極端相接之電晶體，並於閘極使用基本型馬遜平衡器提供0o與180o相位差以饋入本地振盪訊號，射頻訊號經由功率分配器饋入電晶體之汲極與本地振盪訊號混頻，再經由射頻與中頻之分頻電路取出中頻訊號。本電路可提供良好的本地振盪至射頻訊號隔離度與本地振盪至中頻隔離度，並可抑制高次項諧波，得到一良好的轉換損耗與較小尺寸之混頻器。次諧波共面波導二極體混頻器為利用有限地之共面波導作為傳輸線，可減少傳輸線之輻射損耗、抑制高次項模態並可增加佈局的方便性。次諧波鏡像抑制混頻器包含兩組單平衡次諧波混頻器並使用微小化雙巴倫提供兩組單平衡次諧波混頻器本地振盪端之0o與180o相位差，射頻利用藍吉耦合器提供90o相位差，中頻埠則利用設置於晶片外之90o 混合電路結合兩組單平衡次諧波混頻器之中頻訊號。於此電路中針對雙巴倫做微小化設計，相較於基本型之雙巴倫將節省76%的面積，因此得到一極小面積之次諧波鏡像抑制混頻器。
經由量測，次諧波電阻性混頻器於射頻頻率52 GHz時的轉換損耗為13.22 dB，輸入1-dB壓縮點為3 dBm，輸入三階交互調變交叉點為22 dBm，本地振盪對中頻訊號隔離度大於40 dB，本地振盪對射頻隔離度大於35 dB，射頻對中頻隔離度大於15 dB。次諧波共平面波導二極體混頻器的在射頻頻率為60 GHz時，於升頻模式中轉換損耗為12.75 dB，當中頻功率為3 dBm時發生功率1-dB壓縮點；而在降模式中轉換損耗為14.71 dB，當射頻功率為5 dBm時發生功率1-dB壓縮點，IIP3為28 dBm，本地振盪至射頻隔離度在所操作的頻段中皆大於20 dB，而本地振盪至中頻隔離度則大於15 dB，中頻對射頻隔離度大於15 dB。次諧波鏡像抑制混頻器於射頻頻率為42.5 GHz且中頻頻率為2.4 GHz時的轉換損耗為8.4 dB，輸入1-dB壓縮點為2.5 dBm，輸入三階交互調變交叉點為26 dBm，埠對埠訊號隔離度大於25 dB，鏡像抑制比為26.2 dB。

關鍵字

次諧波混頻器 ； 毫米波 ； 混頻器

並列摘要

This thesis investigates V-band miniature mixers. The topology of mixer includes sub-harmonically pumped resistive mixer, CPW sub-harmonically pumped diode mixer and sub-harmonically pumped image rejection mixer. All of the mixers are operated frequency at V-band. The sub-harmonically pumped image rejection mixer contains a miniature Marchand balun. These circuits were fabricated by Win Semiconductor 0.15 μm GaAs pHEMT technology.
The sub-harmonically pumped resistive mixer was connected drains of a pair of transistors. The LO signal was used fundamental Marchand Balun to offer the 0o and 180o differential phases at gate. The RF signal at drain was fed by Power divider and mixed with LO signal, and then used diplexing circuit to draw out the IF signal. This work can provide good LO to IF isolation, LO to RF isolation and suppress high order harmonics. This mixer has a good conversion loss and miniature chip size. The CPW sub-harmonically pumped diode mixer was used finite ground CPW that can reduce radiation loss, suppress high order harmonics and be more convenient to layout. The sub-harmonically pumped image rejection mixer contained two single-balanced sub-harmonically mixers and the LO signal fed by a miniature dual Balun to offer the 0o and 180o differential phases. The RF signal was fed by Lange coupler to offer 90o phase shift. The IF port was fed by 90o hybrid circuit to combine two single-balanced sub-harmonically mixers’ IF signal, which was out of chip. This work has a miniature dual Balun saving the 76% area from fundamental dual Balun. Therefore, the mixer is a miniature area sub-harmonically pumped image rejection mixer.
The measured results of mixers are as follows; for the sub-harmonically pumped resistive mixer, the conversion loss is 13.22 dB, input power at the 1-dB gain compression point is 3 dBm, input third order intermodulation intercept point is 22 dBm, LO to IF isolation is greater than 40dB, LO to RF isolation is greater than 35 dB, and RF to IF isolation is greater than 15 dB. For CPW sub-harmonically pumped diode mixer, in up-converter operation, the conversion loss is 12.75 dB, input power at the 1-dB gain compression point is 3 dBm. In down-converter operation, the conversion loss is 14.71 dB, input power at the 1-dB gain compression point is 5 dBm, input third order inter-modulation intercept point is 28 dBm, LO to IF isolation is greater than 15 dB, LO to RF isolation is greater than 20 dB, and RF to IF isolation is greater than 15 dB. The frequency of sub-harmonically pumped image rejection mixer is shifted to 42.5 GHz The measured conversion loss is 8.4 dB, input power at the 1-dB gain compression point is 2.5 dBm, input third order inter-modulation intercept point is 26 dBm, port to port isolations are greater than 25 dB, and best image rejection rate is achieved as 26.2 dB.

並列關鍵字

sub-harmonic mixer ； mixer

參考文獻

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