Design of Photo Detector and Up-Conversion Mixer for Wireless Photo Detection System

• Main Authors: Cheng-Hong Chang, 張正泓
• Other Authors: Zhi-Ming Lin
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/23245119706388362251

碩士 === 國立彰化師範大學 === 資訊工程學系 === 102 === The major goal of this research was to study and implement a wireless photo detector. A photo detector was to detect the change of free radical in a living being. A photodiode (PD) was used as the photo sensor in the photo detector. The detected data was up-converted to RF (Radio Frequency) signal in the 802.11a frequency band for wireless communication. The principle and the design of each building block will be presented followed by the test results of the system. This study is divided into two phases. The first phase of this research was to design a photo detector chip. The characteristics of different photodiodes were studied. With the integration of photodiode and trans-impedance amplifier, the photo detector was designed and implemented. The photodiode had a forward current of 100μA at a forward bias voltage of 0.776V. It had a reverse current of 366μA at a reverse bias of -15.7V. The gain of the trans-impedance amplifier is 83 ohms. TSMC 0.18μm 1P6M CMOS process technology was used for the implementation of the circuit. This chip was successfully manufactured and tested. The second phase of the research was to integrate the photo detector with an up-converter mixer to work in the frequency band of 802.11a. The Gilbert Mixer was used as the basic structure of the up-converter. The RF frequency was designed to be 5.8GHz. The overall circuitry consumed 4.29mW in simulation. The power gain was 5.8dB and the input power at 1dB compression point was -14dBm. The same process technology, TSMC 0.18μm 1P6M CMOS process, was used for the implementation of the wireless photo detector system.