Ultra Low Power GHz-Band RF DSP for Software Defined Radio Terminals

软件定义无线电（SDR）是一种很有前途的多模式、多频段移动通信解决方案。SDR的关键部件之一是可编程滤波器，即射频/直接频带通滤波器、根滚转滤波器等。虽然最近的数字信号处理（DSP）工作在高频，但使用DSP的滤波器的功耗超过100mW。我们已经提出并实现了电流切断开关电流匹配滤波器（CC-SIMF）。可以显著降低CC-SIMF的功耗。在这项工作中，我们提出了用于SDR终端的开关电流模拟可编程有限脉冲响应（FIR）滤波器。提出了新的可编程抽头电路。此外，还描述了分接电路的实现和测量，并估计了16分接FIR滤波器的功耗。为了实现灵活的射频模块，我们提出了三维多层堆叠SiP的新概念。新的3- d封装概念包括(1)互连长度的设计准则；(2)LSI芯片中的桥接寄存器电路；(3)芯片在系统构建印刷电路板（PWB）上的倒装芯片微凸接技术；(4)多组芯片和PWB的多层堆叠3- d封装；(5)在PWB外围区域100 μm直径的凸点作为垂直过凸总线线。

Software defined radio (SDR) is a promising solution for multi-mode and multi-band mobile communication system. One of key component of SDR is programmable filter, i.e., the radio frequency/immediate frequency band pass filter, the root roll off filter and so on. Although the recent digital signal processing (DSP) operates at high frequency, power of consumption of the filters using DSP is over 100mW.We have already proposed and implemented the current-cut switched current matched filter (CC-SIMF). The power consumption of CC-SIMF can be remarkably reduced.In this work, we propose the switched current analog programmable finite impulse response (FIR) filter for SDR terminals. New programmable tap circuits are proposed. Furthermore, implementation and measurement of the tap circuit are described and power consumption of 16-tap FIR filter is estimated.For realizing flexible RF module, we propose a new concept of 3-D multilayer-stacked SiP. The new 3-D packaging concept includes (1) design guideline for interconnection lengths, (2) bridging register circuits in LSI chips, (3) flip-chip microbump bonding technology of chips onto system-buildup printed wiring boards (PWB), (4) multilayer-stacked 3-D package of several sets of chips and PWB, and (5)100-μm-diameter bumps at peripheral region of PWB as vertical via-bump bus lines.