5G NR脈衝調變極座標發射機模組與雙輸出數位脈波寬度調變器

Abstract

無線通訊技術不斷地發展，已經成為日常生活不可或缺的一部分。在過去幾年之中，對無線通訊的需求呈指數增長，並且隨著遠程醫療保健，物聯網，自動駕駛汽車和虛擬實境應用的出現，無線通訊的需求將進一步增加。發射器需要更好的效能，就必須要有高峰值平均功率比、高效率、寬頻寬以及高線性度等特性。在線性高效率的架構中，脈衝調變極座標發射機架構可以同時實現高效率與高線性度。不僅如此，為了提高極發射器的效率，功率放大器的控制電路「中心式數位脈波寬度調變器」需要提供高頻率、高精準度的脈波輸出。 本論文第一部分使用TSMC 180-nm CMOS製程實作七位元中心式數位脈波寬度調變器，操作頻率為150 MHz，最小脈波寬度為52 ps，並具有相差180°雙相位輸出。最後的可量測PWM 工作範圍為6 % ~ 93%， INL落在-1.24 ~ 1.29LSB之間，DNL落在-1.03 ~ 1.07 LSB之間。 第二部分在實現雙相位脈衝調變極座標發射機上，選用了功率放大器元件、威爾金森功率結合器、前置放大器以及射頻調變器晶片，結合雙路訊號進而提高效率。量測結果顯示ACLR_Lower與ACLR_Upper分別為-30.04 dBc以及-30.23 dBc，輸出功率則可以達到20.12 dBm，DE及PAE分別為19.27 %以及18.43 %。

Wireless communication technology is continuously evolving and has become an integral part of daily life. In the previous years, the demand for wireless communications has increased exponentially which is set to further increase with the advent of remote healthcare, internet of things, autonomous cars and virtual reality applications. If transmitter needs better performance, it must have high peak-to-average power ratio, high efficiency, wide bandwidth and high linearity characteristics. Among linear high-efficiency architectures, the pulse modulation polar transmitter architecture can achieve both high efficiency and high linearity. The first part of this thesis proposed a 150MHz 7-bit centered DPWM using TSMC 180-nm CMOS process, and this circuit generates dual output signal with 180° phase difference. The least significant bit width is 52 ps. The measureable PWM duty cycle is 3% ~ 96%. INL is -1.24 ~ 1.29 LSB, and DNL is -1.03 ~ 1.07 LSB in measurement. The second part of this thesis proposed a dual phase pulse modulation polar transmitter, which consists of Power amplifier, Wilkinson combiner, pre-amplifier and RF modulator. By combing two paths to increase efficiency, measurement result reveals that ACLR_Lower and ACLR_Upper are -30.04 dBc and -30.23 dBc separately. The output power can achieve to 20.12 dBm, while DE and PAE are 19.27 % and 18.43 % respectively.