互補式金氧半場效電晶體微波及毫米波切換器之研製

Abstract

本論文目的在於研究使用互補式金氧半場效電晶體來設計應用於微波及毫米波頻段的切換器。論文中討論了兩種切換器的架構。為了模擬切換器的穿透損耗以及隔離度，也加以建立了簡化的被動電晶體小訊號模型。而非線性模型則是結合了電容和壓控電流源，可用來預測切換器的功率飽和的現象。 第一個將互補式金氧半場效電晶體切換器應用於無線通訊的方法是串聯-並聯架構。利用電晶體基極浮接的技巧可以減小穿透損耗以及提升功率特性。利用商用標準0.18-um的互補式金氧半場效電晶體製程，設計的串聯-並聯切換器在5.8 GHz可達到20 dBm的P1dB，1.1 dB的穿透損耗以及27 dB的隔離度。在2.4 GHz時，此切換器的穿透損耗為0.65 dB以及隔離度為35 dB。此切換器的有效面積只有0.03 mm2。量測值包括功率特性皆和模擬結果相近。 第二個將互補式金氧半場效電晶體切換器應用於毫米波頻段的方法是利用傳導波原理(traveling-wave concept)。使用商用標準0.13-um的互補式金氧半場效電晶體製程，設計了一個單刀雙擲寬頻切換器。利用傳導波原理可增加切換器的操作頻寬。為了因應傳送端及接收端不同的需求，此切換器使用了不對稱的架構。在接收端，此切換器達到小於2.7 dB的穿透損耗以及優於26 dB的隔離度。在傳送端，此切換器達到小於4.4 dB的穿透損耗以及優於14 dB的隔離度。在40 GHz時，此切換器在傳送端可達到13.8 dBm的P1dB。此晶片面積只有0.4 mm2。這是第一個將互補式金氧半場效電晶體使用於毫米波頻段的切換器。 本論文也描述了一個使用傳導波原理所設計的dc-50 GHz單刀雙擲切換器。此切換器是使用商用標準0.18-um的互補式金氧半場效電晶體製程。為了增加切換器的頻寬，前端四分之一波長的傳輸線換成一個串聯的電晶體。從dc到50 GHz，此切換器達到小於6 dB的穿透損耗以及優於38 dB的隔離度。此切換器亦達到17.4 dBm的P1dB在5.8 GHz和19.6 dBm的P1dB在40 GHz。此晶片面積只有0.25 mm2。這是第一個將互補式金氧半場效電晶體使用於dc到毫米波頻段的寬頻切換器。

This purpose of the thesis is to develop the CMOS switches in microwave and millimeter wave frequency range. Two types of the switch topologies are investigated. The simplified small-signal model of passive FET is developed to simulate the insertion loss and isolation; while the nonlinear model which consists of capacitance and voltage-dependent current source is used to predict the power handling capability of the switch. The first method to implement CMOS switch in wireless communication applications is the series-shunt topology. In order to reduce the insertion loss and increase the P1dB, the floating-body technique is used. The series-shunt switch in standard bulk 0.18-um CMOS process achieves a measured P1dB of 20 dBm, an insertion loss of 1.1 dB, and an isolation of 27 dB at 5.8 GHz. It also achieves a measured insertion loss of 0.65 dB and an isolation of 35 dB at 2.4 GHz. The effective chip size is only 0.03 mm2. The measured data agree with the simulation results well, including the power handling capability. The second method to implement the CMOS switch is using traveling-wave concept. A wideband SPDT switch in standard bulk 0.13-um CMOS process is demonstrated. In order to extend the operation frequency, the traveling-wave circuit topology is utilized. Due to the different requirements in the transmit and receive paths, the switch is designed to be asymmetric. In the receive path, the switch achieves a measured insertion loss less than 2.7 dB, a measured isolation better than 26 dB from 27 to 50 GHz. On the other hand, for the transmit path, the switch also achieves a measured insertion loss less than 4.4 dB, and an isolation better than 14 dB from 30 to 63 GHz. At 40 GHz, a measured input P1dB of 13.8 dBm is attained. The chip size is only 0.8 x 0.5 mm2. The measured data agree with the simulation results well. This work is the first CMOS switch in millimeter-wave frequency range. A dc-to-50-GHz SPDT switch using traveling-wave concept in standard bulk 0.18-um CMOS process is also implemented. Instead of the quarter wave length transmission lines, a series transistor can be used for the wide bandwidth operation. The switch achieves a measured insertion loss of less than 6 dB, a measured isolation of better than 38 dB from dc to 50 GHz. The measured input P1dB of 17.4 dBm at 5.8 GHz and 19.6 dBm at 40 GHz is attained. The chip size is only 0.5 x 0.5 mm2. This work is the first CMOS switch from dc to millimeter-wave frequency with a miniature chip size.