TABLE OF CONTENTS Studies performed by the author reveal that reflection-type phase shifters using RF switches and 3 dB CPW couplers are best suited for integration in monolithic applications because of small size and compact packaging. Furthermore, advancement in MEMS technology offers reduced IL in the reflection-type phase shifters operating at mm-wave frequencies. The major loss contributor is the 3 dB CPW Lance coupler due to RF field concentration at the edges of the coupler. This problem is solved by the development and availability of a low-loss, air gap overlay (OL) CPW-MMIC 3 dB couplers with tight coupling. In addition, metal-to-metal contact MEMS series switches can be used for switching the CPW transmission-line sections. Both these techniques can reduce losses significantly in the V-band phase shifters [6].
The 2-bit, V-band (50 75 GHz), reflection-type phase shifter can be designed using the air gap OL CPW 3 dB couplers and metal-to-metal contact MEMS series switches. The four phase states are 0 , ?45 , ?90 , and ?135 . Three CPW line sections comprise of open-ended lines acting like open-ended stubs, each with an electrical length of 30 at the center frequency of 60 GHz and separated by MEMS series switches [6]. The RF signal propagates through the switchable CPW transmission lines and reflects from the open-ended stub. When the phases of the reflected signals of both coupler arms are the same, the RF signals add in phase and...
