Development of microelectromechanical varactors

A varactor with a wide tuning range is essential to adjust the desired frequency band among a wide Gigahertz range and compensate for process deviation as well as effects of temperature. Nowadays, conventional varactors with high quality cannot be available in standard silicon processes; furthermore, they cannot avoid high losses at high frequencies due to the nature of semiconductors. A novel micromachined varactor with a wide tuning range is presented. It can provide a digital selection of capacitance. The electroplating process was singled out to fabricate such a device, with its feature of high aspect ratio. The design has been verified through a finite-element analysis to show a tuning range of 350%.