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91.
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93.
介绍了一种工作在60 GHz频率的具有输出端口间高隔离和全端口匹配特性的小型化变压器巴伦芯片,该芯片采用0.18-μm锗硅BiCMOS工艺设计并加工。通过在60 GHz变压器巴伦的输出端口之间引入隔离电路,提高巴伦的隔离度性能并改善输出端口匹配性能;在此基础上,提出了一种基于左手材料传输线的隔离电路,能大大改善传统隔离电路中分布式传输线尺寸大的问题;为了进一步实现巴伦的小型化,在设计中采用了负载电容补偿技术,同时能改善变压器巴伦输入端口的匹配性能。设计的巴伦芯片经过电磁场仿真,其结果与在片测试结果有较高的一致性,验证了提出的设计方法,设计的巴伦芯片具有全端口匹配和输出端口间高隔离度的特性。基于实测结果,在60 GHz频率处,设计的巴伦芯片实现了超过25 dB的输出端口隔离度和优于18 dB的输出端口回波损耗,且占用尺寸极小,仅为0.022 mm2。 相似文献
94.
针对 AD9361实现DQPSK收发过程中存在的工程实现问题,完成了基于SPI接口的AD9361配置,通过测试定位了:输出端无波形、接收与发射本振时域波形扭曲、输出端谐波分量严重、发射本振与接收本振存在随机相位误差四个疑难问题,采用10MHz SPI时钟、系统时钟设置为40MHz、输出端采用1.4GHz、采用点积叉积进行解调四种方法予以解决。结果表明相关问题解决效果良好,所实现的DQPSK收发性能可靠。 相似文献
95.
In this article, a 7‐GHz to 40‐GHz ultra‐wideband passive double‐balanced mixer MMIC using compact wideband Marchand balun (CWMB) is presented. The CWMB is analyzed and designed by introducing a novel optimal impedance deviation coefficient. A trade‐off between the needed bandwidth and the acceptable insertion loss in an ultra‐wideband passive‐doubly‐balanced mixer design can be made through introducing the optimal impedance deviation coefficient. Finally, to verify the proposed methodology, a compact wideband passive double‐balanced mixer monolithic microwave integrated circuit (MMIC) was designed and fabricated using a standard gallium arsenide (GaAs) pHEMT technology according to the process characteristics. Experimental results show that an ultra‐wideband mixer MMIC is realized from 7 GHz to 40 GHz (140% fractional bandwidth) with a measured conversion loss between 9.5 dB~12.5 dB (in‐band fluctuation less than 3 dB) and a LO‐to‐RF isolation larger than 34 dB. The measurement results are in good agreement with the simulation results. 相似文献
96.
《Digital Communications & Networks》2019,5(3):160-169
Cognitive Radio (CR) uses the principle of dynamic spectrum allocation to improve the utilization of spectrum bands. The estimation of missing data is essential for maintaining an uninterrupted quality of service in the CR. However, the existing methods are not suitable for interpolating missing data in high frequency signals. The storage of spectrum occupancy information is crucial for learning the spectrum usage and prediction. The existing techniques for wideband spectrum sensing suffer from poor edge detection capabilities. This paper proposes an S-Transformation (ST) based approach to solve these problems. For missing samples, the proposed method improves the accuracy of estimation. The ST can also be used to store the spectrum occupancy information. The simulation results show that the proposed scheme outperforms others by improving the accuracy of edge detection. Further, the simple implementation of the ST in the frequency domain is an advantage for the real time application. 相似文献
97.
98.
A wideband common-gate (CG) low-noise amplifier (LNA) with dual capacitor cross-coupled (CCC) feedback and negative impedance techniques is presented for multimode multiband wireless communication applications. Double CCC technique boosts the input transconductance of the LNA, and low power consumption is obtained by using current-reuse technique. Negative impedance technique is employed to alleviate the correlation between the transconductance of the matching transistors and input impedance. Meanwhile, it also allows us to achieve a lower noise figure (NF). Moreover, current bleeding technique is adopted to allow the choice of a larger load resistor without sacrificing the voltage headroom. The proposed architecture achieves low noise, low power and high gain simultaneously without the use of bulky inductors. Simulation results of a 0.18-μm CMOS implementation show that the proposed LNA provides a maximum voltage gain of 25.02 dB and a minimum NF of 2.37 dB from 0.1 to 2.25 GHz. The input-referred third-order intercept point (IIP3) and input 1-dB compression point (IP1dB) are better than –7.8 dBm and –19.2 dBm, respectively, across the operating bandwidth. The circuit dissipates 3.24 mW from 1.8 V DC supply with an active area of 0.03 mm2. 相似文献
99.
针对基于变压器原理的集成巴伦电路进行了系统分析,讨论了理想变压器的特性,给出了一个实际巴伦的等效电路,推导了相应的标准S参数和混合型S参数,并利用ADS仿真结果验证了本文提出的巴伦模型。 相似文献
100.
Huawei Chen 《Digital Signal Processing》2013,23(5):1712-1719
Subband beamforming has found many applications in microphone array processing field, due to its advantages over the fullband counterpart. In this paper, the performance of nearfield subband beamformers for arbitrary arrays in the presence of microphone gain and phase errors is studied from the perspective of statistical analysis. Through the bias and variance analysis of array response, some insightful properties on the robustness of nearfield subband beamformers have been derived. It is shown that the robustness of nearfield subband beamformers is dependent on the source-to-array distance, i.e., the robustness will deteriorate when the source is close to microphone arrays. Moreover, the variation in sound speed, i.e., the temperature in homogeneous environments, has little effect on the robustness performance of subband beamformers. The theoretical results are further verified by several numerical examples on nearfield subband beamformers. 相似文献