近年來，無線射頻辨識系統被廣泛運用在人類的日常生活中，如道路自動收費、智慧家電、電子護照…等等。基於多數無線射頻辨識系統應用的需求，同一讀取器同時讀取多個標籤是系統必要的功能。
本論文實作出多輸入多輸出空分多址存取(MIMO Space Division Multiple Access, MIMO SDMA)無線射頻辨識系統架構。本論文實現之系統大致可分為三個部分，首先，利用虛擬都卜勒定向法估測二個無線射頻辨識標籤之來向角，再利用來向角估測的結果，透過約束式數位波束成型方法將發射訊號指向目標標籤，最後，將不同來向角之接收訊號在接收端經波束成型方法後分離。
本論文使用三支偶極天線組成的均勻圓形天線陣列(Uniform Circular Array, UCA)，於美商國家儀器公司(National Instrument, NI)所開發之軟體無線電平台─向量收發器(Vector Signal Transceiver, VST)，完成多輸入多輸出空分多址無線射頻辨識系統。並於微波無反射實驗室與一般環境完成實驗量測。
實驗結果顯示，本論文系統成功使用虛擬都卜勒定向方法估測空間中二射頻標籤反向散射訊號來向角，並計算出相對應的波束成型權重，將不同指令之發射訊號指向目標標籤，利用約束式數位波束成型方法，在空間上區分二射頻標籤反向散射訊號。

In recent years, radio frequency identification systems have been widely used in daily life, such as automatic road tolls, smart home appliances, electric passports, and so on. Based on the requirements of most RFID applications, reading multiple tags simultaneously by the same reader is a necessary function of a reader.
This work implements a MIMO space multiple division radio frequency identification system. The system can be roughly divided into three parts. Firstly, using pseudo Doppler method technology. It estimates the incident angle of two tag signals. Secondly, via the digital beamforming technology. It sends reader signals to the target tags. Finally, via the digital beamforming technology. It separates the backscatters with different incent angle, and reads two tags simultaneously.
This work develops a SDMA RFID system with a uniform circular array consisting of three dipole antenna using National Instrument, vector signal transceiver. Some experiments was measured in a microwave non-reflection chamber and an indoor laboratory as well.
Experimental results show that the system successfully estimates the incident angle of two tags by pseudo Doppler method and calculates the corresponding beamforming weights. Then, two different reader commands are transmitted to the target tags. Finally, two backscatters are separated by digital beamforming method.

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