Fully CMOS integrated bandpass filter based on mechanical coupling of two RF MEMS resonators

Abstract

The design and test of a frequency channel selection MEMS filter implemented on a commercial CMOS technology is presented. Mechanical coupling between two clamped-clamped beams is used to obtain 0.5% frequency bandwidth in a tunable 26 MHz bandpass filter with a very low bandpass distortion (less than 0.1 dB), which makes the filter suitable for wireless super-hetherodyne transceivers in communications standards such as GSM.Introduction: Great efforts are being made nowadays to develop new MEMS-based signal processors capable of substituting non-integrable elements which are presently employed in wireless system applications [1]. Many studies have focused on developing high-order filters for enhanced frequency response based on electrical or mechanical coupling of several MEMS resonators [2][3][4][5][6][7]. All of these examples use specific technologies for the fabrication of MEMS resonators. Taking into account the improvement in the cost and reliability of the MEMS fabrication if a standard CMOS technology is used, we have previously reported a CMOS-MEMS bandpass filter based on two clampedclamped beam resonators, the frequency responses of which are combined through a CMOS differential amplifier [8]. Following the same technological approach, in this Letter we present a new CMOS-MEMS filter based on the mechanical coupling of two MEMS resonators, in this way a new CMOS-MEMS filter with 120 kHz bandwidth and tunable central frequency can be presented.

A Novel Structure for Design and simulation of a MEMS Resonator for Biomedical Applications

“…By creating some holes on movable plate, resonator return is increased. By reduction of aerial distance and thickness of movable plates, we can increase actuator return but due to construction problems, it is not reduced more than a size [26]. The best choice to increase resonator return is changes in structure and dimensions of beams and creating some holes on movable plate with highest effect on return.…”

Dual frequency MEMS resonator through mixed electrical and mechanical coupling scheme

“…The bandwidth of the resulting filter is given using (2) [27] where B is the required bandwidth, k c is the stiffness of the coupler, k r ( x ) is the stiffness of the resonator at point x from the anchor and k 12 is the normalised coupling coefficient for the given filter type. Once the dimensions of the CC beam have been chosen for the desired frequency, the stiffness of coupling beam can be obtained using (3) [28] and stiffness of CC beam at point x from the anchor was obtained using COMSOL simulation where width ( w c ) of the couplers that can be chosen to satisfy desired bandwidth ( B ) for the filter.…”

Design of a dual‐band waveguide filter based on micromachining fabrication process

“…Micromachining based on lithography, inductively coupled plasma (ICP) etching and electroplating can achieve the precision up to micrometre (μm) scale, which is one of the development trends in THz fabrication technology. In literatures [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], shielding wires, waveguides, antennas, planar transmission lines and cantilever beams based on this fabrication process have realised excellent performance.…”