RF Measurement and Analysis of SOI-LDMOSFETs

• Main Authors: Dung-Yeh Chiang, 江東曄
• Other Authors: Jyh-Ling Lin
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/33106602939985583747

碩士 === 華梵大學 === 機電工程研究所 === 92 === Abstract The packaged SOI-LDMOSFET device’s high frequency characteristics were measured and studied in this thesis, which fabricated by EPISIL TECHNOLOGIES INC. S-parameters were taken from HP8753C network analyzer and the device was biased using class-A. In order to obtain current gain cut-off frequency, we take the transformation between s-parameters and h-parameters. The current gain cut-off frequency of SOI-LDMOSFET approximately equals 100MHz, and the cut-off frequency is about 267MHz by tangent heterodyne method under gate voltage is 2V and the drain-to-source voltage is 20V. In addition, taking 100MHz as the center frequency, we design a high frequency small signal amplifier and its input/output matching networks. First, the circuit was simulated by Microwave Office software, and the actual circuit was measured when the specification of the simulation of designing matching networks conforms with our request. By the result of the measurement, we found that it quite approaches with the simulation values, and the specification achieved our initial request. Because the device after packaging, the high frequency characteristics become complex, therefore this kind of discrete device must depend on the impedance matching to improve its characteristics. We used π- matching network to reduce the input reflection loss to smallest, and obtained the better output power.