基于三维气密陶瓷封装的毫米波射频前端SiP设计

Design of Millimeter Wave RF Front-End SiP Based on 3D Hermetic Ceramic Packaging

摘要:

基于三维气密陶瓷封装技术，以提升集成密度与信号传输性能，实现射频前端系统级封装（SiP）小型化为目的，开展了一项毫米波射频前端SiP的设计与实现研究。采用三维直接覆铜（DPC）陶瓷基板与单片微波集成电路（MMIC）进行三维堆叠设计，并使用陶瓷通孔与铜柱构建类同轴传输结构，实现了射频信号的垂直互连，显著提升了射频前端SiP的集成密度和信号传输效率。通过详细的射频性能分析与关键参数计算，验证了该结构在毫米波频段的有效性。测试结果显示，在工作频段内，发射输出功率为21~22 dBm，接收增益为25~26 dB，接收噪声系数小于3.2 dB，电压驻波比小于2.3，拥有6 bit移相功能步进5.625°和6 bit衰减功能步进0.5 dB，射频前端SiP尺寸仅12×12×4 mm3。

Abstract:

Based on 3D hermetic ceramic packaging technology, a study on the design and implementation of a millimeter-wave RF front-end system in package (SiP) was conducted with the aim of enhancing integration density and signal transmission performance, and achieving miniaturization of the radio frequency (RF) front-end SiP. A 3D stacking design utilizing 3D direct plated copper (DPC) ceramic substrates and monolithic microwave integrated circuits (MMIC) was adopted, and a quasi-coaxial transmission structure formed by ceramic vias and copper pillars was employed to achieve vertical interconnection of RF signals, significantly improving the integration density and signal transmission efficiency of the RF front-end SiP. Through detailed RF performance analysis and key parameter calculations, the effectiveness of this structure in the millimeter-wave frequency band was verified. Test results show that within the operating frequency band, the transmit output power is 21~22 dBm, the receive gain is 25~26 dB, the receive noise figure is less than 3.2 dB, the voltage standing wave ratio is less than 2.3, and the RF front-end SiP features 6-bit phase shift functionality with a step of 5.625° and 6-bit attenuation functionality with a step of 0.5 dB, with dimensions of only 12×12×4 mm3.