| 摘要: | 本文提出了一種低成本，高增益片上兆赫茲(THz)介電共振器天線(DRA)，介電共振器天線由低損耗介電共振器(DR)製作的高阻抗矽材料，並利用0.18-μm CMOS實現晶片上貼片天線饋入訊號，產生所需的電磁模式。利用一片兩英吋的矽晶圓，通過切割所需的尺寸，介電共振器可以很容易的產生出來，厚度500 μm的介電共振器可以激發出高階模式的TEδ,1,7，這大幅增強了天線增益，如果選擇基本模式在兆赫茲頻率下介電共振器厚度約為100 μm，這不僅需要額外的晶圓變薄處理，且晶片在製作的過程中也容易斷裂。
晶片上貼片天線用於激發高階模式TEδ,1,7，此外，它的接地層也防止了電磁場洩漏到有損耗的CMOS矽基底，從而提高了天線的效率，頻率於341 GHz時，模擬天線增益為7.9 dBi，同時提供74％的輻射效率，頻寬為7.3%。
為了分辨介電共振器天線的性能，相同的COMS影像器分別搭配晶片上貼片天線與提出的介電共振器天線，通過比較這兩個影像器的測量響應度，可以獲得介電共振器天線與晶片上貼片天線的增益改善。為了穩健的評估，我提供了三個量測樣本，量測結果表明在327 GHz時，可以獲得6.7 dB的最大增益改善，所以介電共振器天線與COMS影像器的兆赫茲透射成像系統頻率為327 GHz，據了解，這是以兆赫茲頻率工作的第一個高階模式介電共振器天線。;A low-cost and high-gain on-chip THz dielectric resonator antenna (DRA) is proposed in this work. The DRA consists of a low-loss dielectric resonator (DR) made of high-resistivity silicon material and an on-chip feeding patch realized in a 0.18-μm CMOS technology for exciting the desired electromagnetic (EM) mode. The DR can be easily fabricated to the required dimension by wafer dicing of a 2-inch silicon wafer. With a 500-μm thick DR, a higher-order mode of TEδ,1,7 can be excited, which greatly enhances the antenna gain. Such higher-order mode operation also provides a reliable design. If a fundamental mode is selected, the DR thickness is around 100 μm at THz frequencies, which not only requires additional wafer thinning process, but the wafer is also easily broken during the fabrication process. The feeding patch is used to excite the TEδ,1,7 mode. Moreover, its ground plane also prevents the EM field from leaking into the lossy CMOS silicon substrate, which improves the antenna efficiency. The simulated antenna gain can be 7.9 dBi while providing radiation efficiency of 74% at 341 GHz with 7.3% bandwidth. To characterize the DRA performance, an identical CMOS imager is designed to be integrated with the proposed DRA and an on-chip patch antenna, respectively. By comparing the measured responsivity of these two imagers, the gain improvement of the DRA over the on-chip patch antenna can be obtained. Three samples are measured to evaluate the robustness of the proposed antenna over process variation. The measured results show that the maximum gain improvement of 6.7 dB can be acquired at 327 GHz. The proposed DRA with the integrated CMOS imager is also employed to successfully demonstrate a THz transmissive imaging system at 327 GHz. To the best of authors’ knowledge, this is first higher-order mode DRA working at THz frequencies. |
