Frequency multiplier response to spurious signals and its effect on local oscillator systems in millimeter and submillimeter wavelengths
Frequency multiplier response to spurious signals and its effect on local oscillator systems in millimeter and submillimeter wavelengths
复制标题
倍频器对杂散信号的响应及其对毫米和亚毫米波长本地振荡器系统的影响
DOI：
10.1117/12.459195
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发表时间：
2003
影响因子：
3
通讯作者：
I. Mehdi
中科院分区：
文献类型：
--
作者：
G. Chattopadhyay;E. Schlecht;F. Maiwald;R. Dengler;J. Pearson;I. Mehdi
在毫米波和亚毫米波外差仪器中，宽带固定调谐倍频器和频率合成器驱动的宽带功率放大器经常被用作本振(LO)源。在这些频率下，乘法器使用基于砷化镓(GaAs)的肖特基变容二极管作为非线性元件，并且像大多数其他谐波发生器一样容易受到杂散信号干扰。最先进的毫米和亚毫米波长LO源使用MMIC功率放大器，在100 GHz范围内产生超过250 mW的输出功率，并用于驱动后续的乘法器级。由于高输入功率环境和系统中噪声的存在，乘法器容易受到通过偏置线路或通过RF端口的杂散信号干扰。当杂散信号通过乘法器链传播时，它们会产生互调产物，这些产物可能会落在外差仪器的通带内，从而严重降低其性能。研究了毫米波和亚毫米波外差仪中倍频器对杂散信号干扰的响应及其对本振性能的影响。文中给出了谐波平衡的数值模拟结果和实验室实验结果，两者吻合较好。
Broadband fixed-tuned frequency multipliers in conjunction with broadband power amplifiers driven by frequency synthesizers are often used as local oscillator (LO) sources in the millimeter and submillimeter wave heterodyne instruments. At these frequencies the multipliers use Gallium Arsenide (GaAs) based Schottky varactor diodes as the nonlinear element, and like most other harmonic generators are susceptible to spurious signal interference. The state-of-the-art LO sources in the millimeter and submillimeter wavelengths use MMIC power amplifiers producing in excess of 250 mW of output power in the 100 GHz range, and they are used to drive the subsequent multiplier stages. Because of the high input power environment and the presence of noise in the system, the multipliers become vulnerable to spurious signal interference, either through the bias lines or through the RF port. As the spurious signals propagate through the multiplier chain, they generate inter-modulation products which might fall in the passband of the heterodyne instrument and seriously degrade its performance. The issues of frequency multiplier response to spurious signal interference and its effect on local oscillator performance in millimeter and submillimeter wave heterodyne instruments are investigated. Results of numerical harmonic balance simulations and laboratory experiments are presented here, and are found to show good agreement.