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As an alternative to highly constrained hard-wired reconfigurable RF circuits, a motion-enabled reconfigurable circuit (MERC) offers freedom from transmission line losses and homogeneous materials selection. The creation of a successful MERC requires a precise mechanical mechanism for relocating components. In this work, a piezoelectric MEMS actuator array is modeled and experimentally characterized to assess its viability as a solution to the MERC concept. Actuation and design parameters are evaluated, and the repeatability of high quality on-axis motion at greater than 1 mm s−1 is demonstrated with little positional error. Finally, an initial proof-of-concept circuit reconfiguration has been demonstrated using off-the-shelf RF filter components. Although initial feasibility tests show filter performance degradation with an additional insertion loss of 0.3 dB per contact, out-of-band rejection degradation as high as 10 dB, and ripple performance reduction from 0.25 dB to 1.5 dB, MERC is proven here as an alternative to traditional approaches used in reconfigurable RF circuit applications. [ABSTRACT FROM AUTHOR]

There is continuing interest in radio frequency (RF) microelectromechanical system (MEMS) devices due to their ability to offer exceptional RF performance, high linearity and low power consumption. To date, there is an impressive amount of RF MEMS components such as; switches, resonators, varactors, and tunable inductors that have enabled smaller, cheaper and more efficient RF systems. RF MEMS devices contain micromachined components that have the ability to move so that a change in the mechanical state of a device will result in a change to the device’s RF properties. There are many common modes of actuation, including, but not limited to: electrostatic, magnetostatic, piezoelectric, and electrothermal actuation. Although there are attractive aspects and drawbacks to each of these technologies, this paper will focus on advances in the application of piezoelectric actuation, and in particular the use of lead zirconium titanate (PZT), for RF MEMS. [ABSTRACT FROM AUTHOR]

Modeling, fabrication and measurements of tunable inductors are presented where inductance tuning is achieved through mechanical displacement, by piezoelectric actuation, of mutually-coupled coils. The modified Greenhouse method is utilized as a modeling tool to predict the inductance variations as a function of both translation and angular displacement, where coils and traces which are arbitrarily oriented with respect to one another are considered. The use of this modeling approach is verified through experimental results where electrical measurements of inductances are compared with the modeled inductances. The inductance model compares well with the measurements and within 10% of the measured inductance with a 3% mean error. In addition, the impact of the interconnect widths on tunable inductor performances is assessed for both negatively and positively coupled tunable inductor cases, where devices with interconnect widths ranging between 10 and 40 µm are considered. Tuning ratios as high as ~3.9:1 were measured for the negatively-coupled coil designs with 18 V actuation; this corresponds to minimum and maximum quality factors of 5.72 (at 4.05 GHz with a 2.80 nH inductance) and 14.91 (at 2.25 GHz with 10.86 nH inductance), respectively. For the positively coupled inductors, tuning ratios of ~1.2:1 resulted with inductance and peak quality factors of 7.70 nH and ~18 (3.69 GHz), respectively. With 18 V actuation, these values tune to 6.57 nH with a Q ~18 (4.46 GHz). Residual poling stress was found to limit the practical tuning ratio to ~1.8:1 for the negatively coupled coils. [ABSTRACT FROM AUTHOR]