Low cost In-line Phase Shifter (IPS) using electrostatic MEMs for large antenna arrays

Many modern telecommunications, space based, and military applications require antenna arrays to dynamically move the main beam over large scan volumes. Conventional systems have employed mechanical steering methods using either a gimbal or rotary joint architecture. For slow scan rates and monotonic scan volumes, these systems proved adequate. For many modern systems, however, beam agility or multiple simultaneous beams are required that can only be achieved by electronically scanned arrays (ESA). An ESA can be either active or passive but both require phase control at the radiating element or subarray level. ESAs can facilitate multi-target track capability, support multi-function / multi-mode sensor operation (track while scan), provide increased sensorlseeker field-of-regard capabilities, improve low probability of intercept (LPI) characteristics through pseudo-random scan patterns, support point-to-multipoint communications, enable mobile communications, and self-healing networks. The electrical requirements of the space based and military surveillance platforms drives the antenna systems to be large with hundreds and in many cases thousands of radiating elements. Due to the large number of elements required for these high performance antenna array systems, the cost of the phase scanning electronics is one of the driver in reducing the overall cost of the array. Various initiatives are underway at Lockheed Martin Missiles and Fire Control - Orlando to develop low cost ESAs for both military and civilian applications. Of primary interest are low cost phase shifting elements that can be used in passive antenna systems. A particularly promising technology utilizes an In-line Phase Shifter (IPS) to perform the required phase shifting function in a large array environment. This paper describes the IPS concept and presents some preliminary results of implementing a cost effective phase shifter utilizing electrostatic MEMs actuators.