Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：干涉仪利用通道间的相关运算进行测量，是干涉式成像的基本单元。太赫兹成像在安全检查、军事侦查等方面有着广泛的应用前景。将干涉成像测量引入太赫兹领域后，为解决相关运算中高速信号的相位同步问题，该文提出基于低速FPGA控制的交叉同步方案，用低硬件代价解决高速采样信号的相位同步问题，并完成了一套多通道高速数字相关系统。系统的最高采样速率为 5GHz，ADC有效位数大于等于6位，相关器积分时间可调。最后，利用该数字相关器和相应的太赫兹微波元器 件搭建了中心频率为 0.44THz的干涉仪，并得到了清晰的干涉条纹，其线性相位误差小于2°。该研究为今后设计太赫兹干涉成像仪提供了基本单元。
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： To realize remote sensing at sub-millimeter wavelengths,a 450 GHz sub-harmonic mixer was studied. An anti-parallel pair of Schottky diodes is the key component in the mixer. The length of the diodes is 74 mum,and the cutoff frequency of diodes is up to 8 THz. The suspended microstrip matching circuit was built on quartz,and the metal block was cut into two halves. The diode embedding impedance was calculated. The diode package and the matching circuit were integrated in the mixer model. The predicted single side band (SSB) conversion loss is 8. 0 dB,with 4 mW of local oscillator power. Measured results indicate that the lowest measured SSB conversion loss is 14. 0 dB, with 5 mW of local oscillator power. The loss is below 17. 0 dB in the band from 433 ~ 451 GHz,with a 3 dB bandwidth of 18 GHz.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： According to the level of domestic processing technology at present,the circuit structure of anti-parallel diodes with self-bias was proposed. With this structure, not only the difficult problem of processing bias circuit can be solved, but also the odd-order frequency multiplication can be realized efficiently. At the meantime, co-simulation approach was used to simulate the electrical characteristic of the tripler by software HFSS and ADS,including the impact of the parastics. After designing, both the machining and electrical installation are accomplished. The highest measured output power is 3.1 mW at 221 GHz and the output power is more than 2 mW at frequencies of the range 219~227 GHz. These results can provide important reference for future design of high efficiency submillimeter frequency multiplier.
Peer Review Status:Awaiting Review
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