Development of compact 180° phase shifters based on MEMS technology

The paper introduces a novel approach for the design of Micro Electro Mechanical Systems (MEMS) technology based devices whereby, several actuating structures (bridges) are employed to generate required phase shifting application. At present, the development of 180 degrees phase shifter structures have been reported which emphasizes on the concept of maximum miniaturization. Miniature switched capacitors and popular space-filling curves viz., Peano and Hilbert Curves have been exploited to implement novel phase shifter designs. Phase shifters employing both Peano Curve and Hilbert Curve based structures, resulting in 180 degrees phase shift, have been designed, fabricated and characterized to obtain 180 degrees phase shift at 15 GHz design frequency. Measurements are conducted to record Capacitance vs. Voltage response curve, RF performance (Return Loss (S-11 in dB) and Insertion Loss (S-21 in dB) characteristics), differential phase shift (in degrees) and the mechanical frequency of vibration. Devices are reported to actuate at a voltage as low as 8.5 V only, with a capacitance ratio as high as C-r = 7 are added advantages exhibited by the device. Space-filling curve based phase shifters suggest improvement in achieving highly compact structures (1mm x 1 mm and 0.88mm x 0.88 mm) and acceptable performance throughout the frequency range of interest. (C) 2016 Elsevier B.V. All rights reserved.