| Summary: | 碩士 === 國立中央大學 === 電機工程研究所 === 94 === In this thesis, RF front-end circuit for WiMax system is implemented by using tsmc SiGe 0.35�慆 BiCMOS process. This thesis is divided into two parts which are the study on balanced circuit measurement techniques and RF front-end circuits design. The first part is described in chapter 2, mixed-mode S-parameter, the linearity and noise figure measurement of balanced circuits are introduced.
The second part of RF front-end circuit for WiMax system is the main research in this thesis, such as balanced type image rejection low noise amplifier.
Several Image Rejection notch filter was analyzed and two differential notch filter using the second order and third order topology were proposed in this thesis. The implantation of the proposed filter shows the same performance with the simulation results. On the other hand, single to differential image-rejection LNA and fully differential image-rejection LNA were also presented. The theory of the passive second order notch filter and proposed differential active third order notch filter is also verified, respectively.
Following are the measured results of these designs.
Chapter 3-2 is single to differential image-rejection low noise amplifier design .In high gain operating mode, the measurements of single to differential gain is 11.6 dB, input power at the 1-dB gain compression point is -27.5 dBm, input third-order intercept point is -9 dBm., noise figure is 4.89 dB, output port power magnitude difference is 5 dB, image-rejection ratio is 14.9 dB. In low gain operating mode, the measurements of single to differential gain is 6.55 dB, input power at the 1-dB gain compression point is -23.5 dBm, input third-order intercept point is -10 dBm, noise figure is 7.33 dB, output port power magnitude difference is 5.8 dB, image-rejection ratio are 11.5 dB.
Chapter 3-3 are the differential second order and third order notch filter design. For differential second order notch filter, the measurement of zero tuning range is from 2.72 GHz to 3.4 GHz., and the minimum impedance can be low as 0.2 Ohm. For differential third order notch filter, the measurement of zero tuning range is from 2.76 GHz to 3.4 GHz, and the minimum impedance could be low as 0.2 Ohm.. The pole tuning range is from 3.3 GHz to 3.94 GHz, and the maximum impedance can be 100 Ohm.
Chapter 3-4 is the differential image-rejection low noise amplifier design. In high gain operating mode, the measurements of differential mode gain is 9.5 dB, input power at the 1 dB gain compression point is -21 dBm, input third-order intercept point is -5 dBm., noise figure is 8.12 dB, image-rejection ratio are 50.3 dB. In low gain operating mode, the measurements of differential mode gain is -4 dB, input power at the 1-dB gain compression point is -19 dBm, input third-order intercept point is -3.5 dBm, noise figure is 20.48 dB, image-rejection ratio is 34.7 dB.
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