超寬頻雷達相較一般傳統連續波雷達其發射波型為極短的高斯脈衝波，相對頻寬占了20%以上，其優點是因其超寬頻和高分辨力的特性，可獲得目標物的細微動量的時域表現，因此窄頻雷達的技術很難使用在超寬頻雷達。在接收機部分因其波形為極窄波形(ns量級)的瞬時信號，要完整保留回波的精細響應，取樣的問題是一大挑戰，若要取得不失真的波形，在類比數位轉換器上的限制就需要高達數十GHz的取樣率，成本和製造的困難，導致很難實現。本研究用於頻率取樣重建方法，利用傅立葉轉換式，使用混頻器及振盪器等射頻元件滿足積分式，將工作頻帶劃分多個通道，而ADC取樣率的限制速率降低到子頻寬的頻寬範圍，取樣為頻率係數，後端數位處理結合多組低速ADC輸出的值進行綜合得到輸出波型。最後本研究使用商用規格微波元件實作寬頻雷達的接收機雛形，並將原需要的ADC取樣速率降至十倍以上。;The utra-wideband radar transmitting gaussian pulse is different from traditional radar. The bandwidth with respect to the center frequency of the utra-wideband radar is above 20 percent. The utra-wideband radar has advantage in ultra-wideband and high resolution which can get the fine momentum of measuring target in time-domain. However, significant implementation challenges arise as well due to the large bandwidths. The analog-to-digital converters in the receiver must arrive GHz sample rates in order to completely capture the UWB signal whose pulse’s width is nanoseconds, so the cost of radar is very high and it is hard to realize. This paper uses the frequency domain approach to address the problem. This method is using mixer, oscillator and integrator to implement the Fourier transform. In the proposed architecture, multiple channels separating the spectrum of input signal are parallel to one another. Then, the ADC samples the bandwidth of sub channels. Combining these frequency components and inverse Fourier transform can obtain the completely time-domain waveform. Finally this paper not only uses commercial RF components to implement the prototype of broadband radar receiver but also reduces the restriction in ADC sample rate about ten times.
