High resolution MEMS-based switched delay lines

This paper presents a novel approach to tunable delay lines to address the demand for high resolution tunable delay lines for full duplex transceivers. A novel design is presented based on distributed MEMS transmission line technique, which employs switchable transmission line stubs to minimize the unwanted loading in different states. The proposed design is capable of utilizing a minimum number of switches to achieve a delay resolution of 32 picoseconds and a return loss of more than 15 dB for all states over a bandwidth of 100 MHz around 2.45 GHz. A switch module, MM-3100 by Menlo Microsystems composed of 6 MEMS switches integrated on a single-chip, is used to realize the proposed design. Simulation and measurements are in close agreement and their negligible discrepancies are justified. The proposed design promises to be useful in applications such as analog RF interference cancelation, analog signal processing (ASP), and antenna beamforming.