The Design And Characterizing Of Antenna Coupled Terahertz Detector

High-Sensitive detection is the key technology of terahertz science and technology. Among several kinds of THz detectors, the antenna coupled terahertz detector has been widely used and researched. The NbsN6 microbolometer THz detector array as an antenna coupled THz detector has the advantages of easy fabrication, high sensitivity, fast response time, and easey for super-large array integration. However, in terhertz range, the substrate thickness of the terahertz detector chip is matched with the wavelength, therefore the design and characterization of the antenna coupled detector face several difficulties caused by the interference of the substrate. For optimizing and characterizing the NbsN6 microbolometer antenna coupled detectors, we do some research about its design and characterization. The main contents in this dissertation are classified as follows:1. The design of the THz antenna for the NbsN6 microbolometer. THz antenna is used to enhance radatiation coupling ability of the detector. One of the main problems in antenna design is the impedance match between the antenna’s input impedance and the load’s impedance, the matching efficiency determines the detection performance of the device, such as voltage response. The core of the NbsN6 microbolometer is the microbridge fabricated by the NbsN6 film, its room temperature resistance is in the range of 0.6K to 3K ohm. Generally planar self-complementary antenna characteristic input impedance is only 60π ohm, which can not meet the high impedance matching requirements of the NbsN6 microbolometer. We simulated and designed a high-impedance half-dipole antenna at 0.2THz. We calculated the antenna’s input impedance, the reflection coefficient S11, the current distribution and the far-field distribution. In addition, we have studied the resonant structure’s affect to the antenna. According the optimized results, we fabricated the 0.2THz NbsN6 microbolometer antenna coupled terahertz detector array, the experimental results showed that the device has excellent voltage response from 0.22-0.33 THz.2. In the THz domain, the physical area of the device’s plannar antenna structure is smaller than the area of the incident beam. The effective response of the antenna coupled terahertz detector could present the antenna’s actually received power. We proposed an experimental method-Deconvolution method to measure the effective receiving area of the detector. By this method, we can caclucate the effective response of the antenna coupled detector accurately. When the bias current is 0.19mA, the DC voltage is-760 V/W and the experiment measured effective response voltage is 480 V/W. The results present that the Nb5N6 microbolometer effective receiving area is 7.4 times the physical size (the size of the main antenna), the effective response is 63% of the DC voltag. The experimental method objectively reflects the performance of the device used in practical optical systems, and the method provides an effective method for antenna coupled detector characterication in terahertz region. In addition, the result provide a reference for setting the size of the antenna array unit.