150 GHz低雜訊放大器與300 GHz次諧波混頻器之設計

Abstract

本論文講述了太赫茲頻段中低雜訊放大器與次諧波混頻器的設計與實現，並以此分為兩大部分，首先第一部分介紹了一種在D頻段具有極高增益的低雜訊放大器，其由40奈米CMOS製程所實現四級的Gmax-core放大器。傳統上，構建Gmax-core具有無限多種組合方式，通常使用三種線性、無損及互易的元件所組成嵌入網路，然而本論文提出了一種使用變壓器所構成的Y嵌入網路，能夠改良傳統上只能使用單一偏壓的侷限性，將閘極與漏極分開偏壓，這種方法不僅降低了功耗，也實現了更高的增益與更低的雜訊指數。測量結果表示其在143.5 GHz達到峰值增益27.74 dB，3 dB帶寬為7 GHz，雜訊指數約為9 dB。 第二部分設計了兩種300 GHz可上/下變頻的次諧波混頻器，皆為使用65奈米CMOS製程，藉由挑選不同的電路架構，能使電晶體的電阻值產生LO的周期性變化，最後經由並聯電晶體來產生LO的二倍頻再與IF/RF端進行上/下變頻。其模擬結果表明其轉換增益分別為-16.4 dB與-20.4 dB，皆無使用DC pad，不僅大幅縮小晶片面積，並實現了零功耗。

This paper discusses the design and implementation of low-noise amplifiers and sub-harmonic mixers in the sub-terahertz and terahertz frequency bands, dividing the content into two main sections. Firstly, the initial part introduces a low-noise amplifier with extremely high gain in the D-band, composed of a four-stage Gmax-core amplifier realized in a 40-nm CMOS process. Traditionally, constructing the Gmax-core offers infinitely many combinations, typically achieved using a network composed of three linear, lossless, and reciprocal elements. However, this paper proposes a Y-embedded network constructed with transformers, which improves upon the limitations of traditional single-bias configurations. By biasing the gate and drain separately, this method not only reduces power consumption but also achieves higher gain and lower noise figure. Measurement results demonstrate a peak gain of 27.74 dB at 143.5 GHz, with a 3 dB bandwidth of 7 GHz and a noise figure of approximately 9 dB. In the second part, two sub-harmonic mixers with tunable frequency up to 300 GHz are designed, both utilizing a 65-nm CMOS process. By selecting different circuit architectures, the resistance value of the transistors can be varied periodically to generate LO frequency. Finally, the LO doubling is achieved by parallel transistors, enabling up/down frequency conversion with IF/RF ports. Simulation results show conversion gains of -16.4 dB and -20.4 dB respectively, without using DC pads, leading to significant reduction in chip area and zero power consumption.