Research And Design Of Microwave Packaging For Multi-channel RF Optical Transceiver

The Faster connection rate,larger transmission bandwidth,and wider coverage are required for future mobile communication.Radio over Fiber（Ro F）is considered to be a promising solution because it directly transmits RF signals between the Remote Radio Unit（RRU）and the Building Baseband Unit（BBU）.So it is conducive to the realization of high spectrum efficiency,ultra-low latency,and low-cost infrastructure.In the Ro F system,the optical transceiver is a crucial component.Therefore,preparing RF optical transceiver modules with high linearity,low noise,and large dynamic range is essential.For the high bandwidth and high linearity requirements of future mobile communications,the factors that affect the performance of RF optical transceivers in microwave packaging are analyzed detailedly in this thesis.A four-channel A-Ro F optical transceiver suitable for B5G mobile fronthaul is prepared and tested.The main research content is as follows:（1）The main performance indicators of the RF optical transceiver are analyzed,such as noise,scattering parameters,and spurious-free dynamic range（SFDR）.Based on the theory of signal integrity,the application of impedance and transmission line principles in the optical transceivers is analyzed.（2）The layers and layout of the printed circuit board（PCB）are designed,the line width of RF transmission is optimized,and the important structures,including wire-bonding,GPPO Connector,and the impedance matching of the Laser Diode were modeled and simulated.Under the guidance of theory and simulation analysis,the three major structures were optimized to improve the performance of the optical transceiver.Finally,in the frequency range of 0～20GHz,the insertion loss of each channel is below 1.5d B,and return loss is above15d B.（3）The design and preparation of a high-performance integrated four-channel direct modulation RF optical transceiver are completed,and the key performance of the transceiver is tested in detail.The insertion loss is less than 5d B in the range of 0～15GHz,and the SFDR can reach more than 94d B·Hz^2/3.（4）The verification of A-Ro F based mobile fronthaul system is completed.The 5bands64QAM-OFDM signal is used,the center frequency is 2～12GHz.The EVM of each channel is below 3.2%after 15.5km standard single-mode fiber transmission,which shows that the module can satisfy the requirements of the B5G mobile fronthaul.