TABLE OF CONTENTS Recent research and development activities on MEMS switches and air gap 3 dB CPW couplers have demonstrated substantial reduction in IL, fabrication cost, and size of the elements, the critical elements required in the design of multi-bit phase shifters operating at mm-wave frequencies. These research activities further reveal that the phase shifters using the surface micromachined technology offer significant reduction in power consumption, larger phase shift per decibel loss (i.e., 75 /dB at 60 GHz), and minimum IM distortions compared to those using PIN-diodes or FETs. Furthermore, the reflection-type distributed MEMS phase shifter is fully compatible with monolithic technology, which yields low fabrication cost.
Design aspects and critical elements of a 2-bit, V-band, reflection-type MEMS phase shifter have been described in Section 6.7. Note that 1-bit phase shifter needs two sections capable of yielding 0 and 180 phase states, a 2-bit phase shifter needs three sections or three switch pairs as shown in Figure 6.10 capable of providing 0 , 45 , 90 , and 135 phase states. The 3-bit, V-band MEMS phase shifter will need four sections or four switch pairs using the same air gap CPW couplers and direct contact-type MEMS series switches as mentioned in the 2-bit,V-band MEMS phase shifter case involving three separate sections. In the case of a 3-bit, V-band phase shifter, four sections are needed to provide eight phase states, namely, 0 , 45 , 90 , 135 , 180 , 225 , 270 , and 315 phase states. Essentially,...
