Ku波段超宽带射频发射机关键技术研究

发布时间：2018-01-21 04:38

本文关键词： 发射机宽带 Ku波段 5G　出处：《东南大学》2017年硕士论文　论文类型：学位论文

【摘要】：低频段存在各种通信标准与协议,频谱资源正变的越来越紧缺,而高频段拥有丰富的可用频谱资源以及更大的连续带宽,研究更高频率、更大带宽的通信系统是大势所趋。在此背景下,本设计的重点在于研制工作于Ku波段的,带宽达到1GHz的超宽带移动通信射频发射机。1)根据系统的要求,通过仔细分析无线通信射频系统设计中常见的一些考量,包括调制与载波方案,射频收发信机结构,射频电路存在的固有缺陷对射频性能的影响等,确定了发射机的系统方案,进行了组合频率仿真、链路预算与增益分配,确定了各个模块的实现方案,为射频系统的整体设计提供了参考依据。2)根据系统方案和模块方案,研制了发射机中的各个模块,包括中频本振、正交调制器、SIW滤波器、镜像抑制上变频器以及功率放大器等。其中,中频本振模块采用锁相环结构,本振频率为1.6GHz,使用外部参考锁定的方式方便收发系统同步。调制器模块采用I/Q单端基带接口,经差分放大器转换为差分信号送入正交调制器,外加直流偏压电路,实现本振抑制。上变频器模块采用镜像抑制技术,并设计了一款SIW结构的射频滤波器,以获得良好的带外抑制效果。功率放大器模块采取了适当的外部输入匹配,起到补偿和均衡的作用,使得功放整体平坦度小于3dB。各模块的测试均比较理想。3)将研制的各个模块组合成一个完整的Ku波段发射机,开展了较详细的测试。结果显示,工作频率为13.5GHz-14.5GHz,模拟带宽达1GHz,发射机发射频谱无明显杂散,APC动态范围超过50dB,最大输出功率达到33dBm,发射机中频子系统平坦度小于1.5dB,射频前端平坦度小于2.5dB。还对收发信机的整体调制精度进行了测试,滚降因子设为0.25,BPSK调制800Msps码率的EVM约0.33,BPSK调制400Msps码率的EVM 约 0.11,QAM16 调制 400Msps 码率的 EVM 约 0.08,QAM16 调制 200Msps 码率的 EVM 约 0.04,QAM64 调制 100Msps 码率的 EVM 约 0.03,QAM128 调制 1OMsps 码率的EVM约0.02,测试结果表明该收发机满足使用要求。研制的发射机已经交付给客户使用。
[Abstract]:There are a variety of communication standards and protocols in the low frequency band, and the spectrum resources are becoming more and more scarce, while the high frequency band has abundant available spectrum resources and more continuous bandwidth to study higher frequency. The communication system with larger bandwidth is the trend of the times. Under this background, the emphasis of this design lies in the development of Ku-band. According to the requirements of the system, some common considerations in the design of wireless radio frequency system, including modulation and carrier scheme, are carefully analyzed. The structure of RF transceiver and the influence of inherent defects of RF circuit on RF performance are determined. The system scheme of transmitter is determined, and the combined frequency simulation, link budget and gain allocation are carried out. The implementation scheme of each module is determined, which provides a reference for the overall design of RF system. 2) according to the system scheme and module scheme, each module in the transmitter, including if local oscillator, is developed. The quadrature modulator has a SIW filter, a mirror rejection upconverter and a power amplifier. The intermediate frequency local oscillator module uses a phase-locked loop structure with a local oscillator frequency of 1.6 GHz. The modulator module adopts I / Q single terminal baseband interface, which is converted into differential signal by differential amplifier and fed into quadrature modulator, plus DC bias circuit. Local oscillator suppression is realized. The upconverter module adopts mirror image suppression technology, and a RF filter with SIW structure is designed. In order to obtain a good out-of-band suppression effect. The power amplifier module takes appropriate external input matching, plays the role of compensation and equalization. The overall flatness of power amplifier is less than 3 dB. The test of each module is ideal. 3) the developed modules are combined into a complete Ku-band transmitter, and more detailed tests are carried out. The results show that. The operating frequency is 13.5GHz ~ 14.5GHz, the analog bandwidth is 1GHz, and the transmitter emission spectrum has no obvious spurious APC dynamic range of more than 50dB. The maximum output power is 33dBm, the if subsystem flatness is less than 1.5dBand the RF front-end flatness is less than 2.5dB.The overall modulation accuracy of transceiver is also tested. The rolling factor is set to 0.25 BPSK modulation 800Msps code rate EVM about 0.33 BPSK modulation 400Msps code rate EVM about 0.11. QAM16 modulates 400Msps with a EVM of about 0.08 and QAM16 modulates the EVM of 200Msps about 0.04. The EVM of 100Msps modulated by QAM64 is about 0.03and QAM128 modulates the EVM of 1OMsps. The test results show that the transceiver meets the operational requirements and the developed transmitter has been delivered to the customer.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5;TN830

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