Abstract
During the period of World War II, radar has been created for searching the position of enemy forces effectively or distinguishing the troops from a long distance. After the Second World War, radar has been highly developed because of the progress of Scientific and technological in different fields. Compared with other sensing mechanisms, like Infrared, Ultrasound or Laser, radar is relatively unaffected by other Environmental factors and more stable in a wide range of sensing. Today radar has overcome many limitations and become many daily applications in our life. The importance of radar is steadily on the increase. In the beginning of receiver in a radar system, a RF signal is received by an antenna. And it will be gained by the low noise amplifier (LNA) that the back-end circuit can deal with. After passing the down-conversion Mixers of the front-end circuit, it will be brought to the baseband circuit for amplifying the signal. And the noise will be filtered by a higher-stage low pass filter. In the last, the analog information will be referred to an ADC for the new digital information that we expect. In short, the baseband circuit is to amplify the signal and eliminate the noise outside the cutoff frequency. This thesis presents an analog baseband circuit design. It includes an unit gain buffer, a programmable gain amplifier, a fourth-order Butterworth low pass filter, a second-order equalizer and another unit gain buffer. The circuit has zero to hundred dB programmable gain. The cutoff frequency is 20MHz. It also has a nice phase response in passband frequency. The baseband circuit is implemented with TSMC 65nm process, operating at 1.2 volt.