Noise Reduction Techniques in RFICs and Mobile Handsets

Abstract

With the widespread use of the electronic products for mobile communication, the sensitivity problem has become a major issue of perform a certification. The generated system noises or interferences not only affect the coverage range of the system but also system sensitivity and it will be more obstacles in the development of mobile handsets. At the integrated circuit (IC) level, to get better system sensitivity, low noise and low power operation are required. To meet these requirements, the realization of high quality factor (Q) of the integrated passive devices, especially inductors, is needed. However, traditional high Q inductors ordinarily occupy a large chip area, reducing the size of the chip is challenging and results in serious bottlenecks attempting to decrease chip cost. One method for decreasing the size of passive inductor is a stacking technique. However, due to the critical shortcomings of stacked spiral inductors including a low self-resonance frequency (fsr) and Q, traditional stacked spiral inductors are not commonly used. First, this dissertation presents miniature differential stacked spiral inductor (DSSI) structures which include a higher fsr and Q. At the system level, to improve the sensitivity of the transceiver, the intra-system interference (EMI) problems have to be considered in transceiver design steps. Because of the trend of miniaturization and increasing functions, the up-to-date printed circuit board (PCB) of the mobile handset includes a large number of radio frequency (RF) components and digital components. Therefore, many circuit components, for example, baseband chip, memory module, RFIC, antenna, etc., are mounted on the single PCB. This state results in more severe interference between digital parts and RF parts. If coexistence of digital components and RF components on the single PCB are not taken into account as a first development stage, the serious system sensitivity degradation issue may arise. This dissertation presents the coupling mechanisms and decoupling methods between the digital part and the RF part (antenna part). These techniques can provide to get higher sensitivity of the system in real sensitivity problems.