電阻式混波器之設計與60 GHz通道量測

Abstract

這篇論文可分為兩部分。第一部分是關於電阻式混波器的研究。由於電阻式混波器幾乎無功率消耗以及出色的線性度，讓他們被廣泛地應用在毫米波設計上，。論文中，我們將簡短介紹電阻式混波器混頻的機制。基於電阻式混波器的原理，我們設計了兩個混波器。第一個為增進LO埠到RF埠隔離度的雙九十度相差混波器。以升頻混波器來說，漏到功率放大器輸入端的LO訊號將與RF訊號經由天線發射出去，這會造成系統干擾。以降頻混波器來說，漏到低雜訊放大器輸出端的LO訊號會影響放大器本身的性能，甚至造成震盪。這部分我們也額外列出了幾個能改善LO埠到RF埠隔離度的混波器架構。另一個設計的混波器為二倍次諧波混波器。它需要的LO頻率只要一般基頻混波器的一半。次諧波混波器的好處為它可以降低LO漏到RF與IF埠的訊號。我們額外使用汲極偏壓的技術進一步改善混波器的線性度。 論文的第二部分為60 GHz通道量測。首先，我們利用號角天線對號角天線來驗證路徑損耗，使用的天線極化為垂直對垂直與水平對水平。假如我們知道室內材料的穿透與反射損耗，可以幫助我們預估在接收端接收到的功率。我們選擇塑膠隔板、木板與強化玻璃來進行以下的實驗。天線的波束角與增益分別為十度與22.73 dB。在量測穿透損耗時，我們不僅量天線正對時的損耗值，在不超過天線波束角之下，我們移動接收端的號角天線來檢視材料的均勻度。在量測反射損耗時，我們量測的入射角為10度到80度。在量測穿透與反射損耗時，垂直對垂直極化與水平對水平極化所造成的損耗差異，我們亦做了比較。

The thesis consists of two parts. The first part concerns the study of resistive mixer. Resistive mixers are widely used in mm-wave designs because of their virtually zero power consumption, excellent linearity. We will give a brief introduction of how resistive mixers perform mixing. Based on resistive mixers, there are two mixers designed in this thesis. The first one is a dual quadrature mixer, which is to improve the LO-to-RF isolation. For an up converting mixer, the LO leakage to the input of the power amplifier is fed with the RF signal and transmitted through the antenna. It could cause interference for the system. For a down converting mixer, the LO leakage to the output of the low noise amplifier (LNA) may affect the performance of LNA or even cause oscillations. We also list some other existing topologies of mixer for the enhanced LO-to-RF isolation purpose. The other mixer designed is the ×2 subharmonic resistive mixer. It needs only half the LO frequency as the fundamental mixer does. The advantage of the subharmonic mixer is the reduction of LO leakage into the RF and IF ports. We also apply the drain bias technique to further improve the linearity of the subharmonic resistive mixer. The second part of the thesis is 60 GHz channel measurement. We start with the path loss verification by using horn-to-horn measurement with vertical-to-vertical and horizontal-to-horizontal polarizations. If we know the penetration loss and reflection loss of indoor materials, we can predict how much power is received at the Rx side. We choose the plastic partition, the wooden boards, and the tempered glass for the following measurement. The beamwidth and the gain of the horn antennas are 10 degrees and 22.73 dB. For the penetration loss, we not only measure the normal incident penetration loss but also move the Rx antenna within its beamwidth to see if the materials are homogeneous. For the reflection loss, we measure it from the incident angle 10 degrees to 80 degrees. We make the comparison between v-to-v and h-to-h polarizations for the measurement of the penetration loss and the reflection loss both.