RF Front-end Circuits Suitable for Bio-medical Wireless Sensor Network
Date Issued
2007
Date
2007
Author(s)
Li, Wei-I
DOI
en-US
Abstract
In recent years, the applications of wireless communication become more and more important. Wireless communication plays an essential role in our daily lives. The market of the wireless applications grows up gradually. The demands of the wireless products also increase rapidly. Therefore, the miniaturization and low costs will be the first topic we are interested in.
This thesis is going to discuss a low-voltage wireless receiver with small chip area. A fully monolithic receiver is implemented in chapter 3. The supply voltage is only 1.8V with the total power dissipation of 7.2mW. The die even just occupies 173.1um by 186.9um excluding pads. This receiver is one kind of ASK (Amplitude shift keying) receivers, called OOK (On-off shift keying) receiver, and it can receive OOK signals and demodulate them perfectly. The experimental results show that a sensitivity of –61dBm with a receiving power dynamic range of 44dB is achieved at 433MHz frequency band. The maximum data rate can be even up to 6Mbps. Because of miniaturization and low power consumption, this receiver is suitable to be integrated into a wireless integration chip such as an implantable biomedical wireless sensor network.
The circuit technique for the application of signal strength indicator is realized. A seven-stage amplifier architecture was derived under minimum power consideration. Each gain cell adopts current-reuse structure rather than the conventional diode load for low supply voltage. This circuit can also receiver the wireless OOK signal in addition to RSSI. The prototype occupies an active area of 0.115mm2 (W/O pad). It consumes 36.75mW from a 2.5V power supply.
On the other hand, due to the maturity of passive RFID, the development of active RFIC would become an urgent goal for the market. Therefore, we will design a RF front-end circuit with an existing microcontroller based on the industry-standard 8051 architecture. The UHF band is selected from 800MHz to 1GHz, which could cover the popular frequencies, 868MHz and 915MHz, for RFID products.
Subjects
無線
生醫
射頻
接收機
強度偵測
開關鍵
低雜訊放大器
混頻器
wireless
bio-medical
RF
receiver
RSSI
OOK
LNA
mixer
Type
thesis
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