以集總元件設計之寬頻放大器與切換器

Abstract

近年來，無線通訊快速發展，受到工業界及學術界的高度關注，紛紛發展新的技術和產品，6GHz以下的頻段已廣泛的使用在人們的生活中。由於資訊傳送量越來越大，運算處理速度越來越快，未來勢必走向寬頻的無線通訊。 本論文研究使用集總元件設計用於傳統收發機前端部份的寬頻放大器與切換器。第一部份是探討低雜訊放大器與單級串接分佈式放大器的設計，首先我們實現了一個2GHz的低雜訊放大器，所使用的是Avago的ATF-33143擬高速電子遷移率電晶體，電路操作在4V偏壓，以FR4印刷電路板當作載板，架構使用2級的有損匹配（lossy match），設計增益為21dB，輸出和輸入回饋損失為10dB，輸出功率1dB增益壓縮點（P1dB）為22dBm，功率增加效率為39.6%，雜訊參數為1.97dB。 而使用行進波的理論，可使放大器有寬的運作頻帶，製作了兩個電路，第一個電路實現了一個1GHz-5GHz的寬頻放大器，所使用的是NEC的NE32584C 異質接面場效電晶體，電路操作在2V偏壓，以FR4印刷電路板當作載板，架構使用微帶線的3級單級串接分佈式放大器（CSSDA），設計增益為25±3dB，輸出和輸入回饋損失為10dB，輸出功率1dB增益壓縮點（P1dB）為11.5dBm，雜訊指數約為8dB。 第二個電路實現了一個1GHz-6GHz的寬頻放大器，也使用NEC的NE32584C 異質接面場效電晶體，電路操作在2V偏壓，以FR4印刷電路板當作載板，架構使用共平面波導的3級單級串接分佈式放大器（CSSDA），設計增益為20±3dB，輸出和輸入回饋損失為10dB，輸出功率1dB增益壓縮點（P1dB）為11.5dBm，雜訊指數約為7.75dB。 第二部份是探討單刀雙擲行進波切換器，使用集總元件和FR4印刷電路板當載板，使用頻率為0.1GHz到4.8GHz，操作在0V與-3V，插入損失小於5dB，隔離度大於18.2dB，輸出輸入回饋損失大於7.5dB和9dB，輸出功率1dB增益壓縮點為15dBm，開啟和關閉狀態能很明顯地分辨，電路優點為低成本、容易製作。

With the rapid progress of wireless communication in recent years, it has received great attention from both the industry and the academic circle. As new products applying the technology are developed, applications utilizing frequency band below 6 GHz can be widely seen in our daily life. Because the amount of data transmission and processing speed increase, wide band will definitely become a trend in wireless communication in the future. This thesis presents a systematic design approach to realize a broadband amplifier and switch in a conventional transmitter front-end using lumped elements. The first part treats the design of low noise amplifier and cascaded single-stage distributed amplifiers. We have implemented a 2GHz low noise amplifier at fisrt, which uses Avago ATF-33143 pHEMT operating with 4V supply on FR-4 printed circuit board. The architecture of this circuit is a 2-stages amplifier using lossy match. Measurement results reveal that the amplifier exhibits a small signal gain of about 21dB with input/output return loss of 10 dB. The 1-dB compression point（P1dB）is about 22dBm, power added efficiency is about 39%, noise figure is 1.97 dB. Using traveling-wave theory, this amplifier has the characteristic of wide operation bandwidth. We implemented two circuits. One of them is a 1GHz-5GHz broadband amplifier, which uses NEC NE32584C hetero-junction FETs operating with 2V supply on FR-4 printed circuit board. The architecture of this circuit is a 3-stages cascaded single-stage distributed amplifier (CSSDA) using microstrip line. Measurement results reveal that the amplifier exhibits a small signal gain of about 25±3dB with input/output return loss of 10dB. The 1-dB compression point（P1dB）is about 11.5dBm, noise figure is about 8dB. The other is a 1GHz-6GHz broadband amplifier, which also uses NEC NE32584C hetero-junction FETs operating with 2V supply on FR-4 printed circuit board. The architecture of this circuit is a 3-stages cascaded single-stage distributed amplifier (CSSDA) using coplanar waveguide. Measurement results reveal that the amplifier exhibits a small signal gain of about 20±3dB with input/output return loss of 10dB, stability factor of more than 98. The 1-dB compression point（P1dB）is about 11.5dBm, , noise figure is about 7.75dB. The second part of the thesis involves the design of single-pole double-throw（SPDT） traveling-wave switch, also implemented on FR-4 printed circuit board using lumped discrete components. The operating frequency of this switch is from 0.1GHz to 4.8GHz, using 0V and -3V switch supply voltage. The input and output return losses are better then 9dB and 7.5dB, respectively, while output 1-dB compression point（P1dB）is about 15dBm. On-state and off-state of the switch can be differentiated unambiguously. Advantages of circuits are low cost and easy implementation.