Contents I. Introduction
The use of electronically steered arrays is becoming increasingly necessary to meet the performance requirements of modern radar and communication systems 3-bit RF MEMS phase shifter. The substrate is 75-–thick semi-insulating GaAs with 2.1--thick gold traces. The circuit is 3.5 × 2.6 mm in size. [1]. Phase shifters are critical components in such arrays and can often become the performance-limiting component of the system. Traditionally, phase shifters using GaAs transistors configured to switch between different line lengths or filters have been used, but such transistor switches tend to be lossy. Thus, the best pseudomorphic high electron-mobility transistor (pHEMT) 4-bit phase shifter reported to date exhibits an average loss of 6.5 dB at -band [2]. In contrast, recently several RF microelectromechanical system (MEM)-based phase shifters have been reported that exhibit greatly reduced insertion loss [3]–[5]. This paper expands upon these results by demonstrating very low loss and parasitics, but over much larger bandwidths and in a more compact and manufacturable assembly. Furthermore, the monolithic integration of pHEMT monolithic-microwave integrated-circuit (MMIC) devices with the RF MEMS switches used here has already been demonstrated [6]. Consequently, monolithically integrating the phase shifter with -band amplifiers, oscillators, and mixers is a straightforward approach to further reduce overall antenna cost and complexity.
